[Federal Register Volume 65, Number 91 (Wednesday, May 10, 2000)]
[Proposed Rules]
[Pages 30194-30274]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-10763]
[[Page 30193]]
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Part II
Environmental Protection Agency
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40 CFR Parts 141 and 142
National Primary Drinking Water Regulations: Ground Water Rule;
Proposed Rules
Federal Register / Vol. 65, No. 91 / Wednesday, May 10, 2000 /
Proposed Rules
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 141 and 142
[WH-FRL-6584-4]
RIN 2040-AA97
National Primary Drinking Water Regulations: Ground Water Rule
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of proposed rulemaking.
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SUMMARY: EPA is proposing to require a targeted risk-based regulatory
strategy for all ground water systems. The proposed requirements
provide a meaningful opportunity to reduce public health risk
associated with the consumption of waterborne pathogens from fecal
contamination for a substantial number of people served by ground water
sources.
The proposed strategy addresses risks through a multiple-barrier
approach that relies on five major components: periodic sanitary
surveys of ground water systems requiring the evaluation of eight
elements and the identification of significant deficiencies;
hydrogeologic assessments to identify wells sensitive to fecal
contamination; source water monitoring for systems drawing from
sensitive wells without treatment or with other indications of risk; a
requirement for correction of significant deficiencies and fecal
contamination (by eliminating the source of contamination, correcting
the significant deficiency, providing an alternative source water, or
providing a treatment which achieves at least 99.99 percent (4-log)
inactivation or removal of viruses), and compliance monitoring to
insure disinfection treatment is reliably operated where it is used.
EPA believes that the combination of these components strikes an
appropriate regulatory balance which tailors the intensity or burden of
protective measures and follow-up actions with the risk being
addressed. In addition to proposing requirements for ground water
systems, EPA requests comment on ways to address the problem of
transient providers of water who furnish drinking water to large
numbers of people for a limited period of time. One possible solution
is to adopt alternative definitions for ``public water systems'' which
is currently defined as ``one that serves 25 or more people or has 15
or more service connections and operates at least 60 days per year. EPA
is only requesting comment on this issue. The Agency is not today
proposing to change the definition of ``public water system ,'' or
modify related provisions. If EPA decides to take action on this issue,
EPA will publish a proposal at a later date.
DATES: The EPA must receive comments on or before July 10, 2000.
ADDRESSES: References, supporting documents and public comments (and
additional comments as they are provided) are available for review at
EPA's Drinking Water Docket #W-98-23: 401 M Street, SW, Washington, DC
20460 from 9 a.m. to 4 p.m., Eastern Time, Monday through Friday,
excluding Federal holidays.
You may submit comments by mail to the docket at: 1200 Pennsylvania
Ave., NW, Washington, DC 20460 or by sending electronic mail (e-mail)
to [email protected]. Hand deliveries should be delivered to: EPA's
Drinking Water Docket at 401 M Street, SW, Washington, DC 20460.
For access to docket materials, please call 202/260-3027 to
schedule an appointment and obtain the room number.
FOR FURTHER INFORMATION CONTACT: For general information, contact the
Safe Drinking Water Hotline, telephone (800) 426-4791. The Safe
Drinking Water Hotline is open Monday through Friday, excluding Federal
holidays, from 9 a.m. to 5:30 p.m. Eastern Time. For technical
inquiries, contact the Office of Ground Water and Drinking Water (MC
4607), U.S. Environmental Protection Agency, 1200 Pennsylvania Ave.,
N.W. Washington, DC 20460; telephone (202) 260-3309.
SUPPLEMENTARY INFORMATION:
Regulated Entities
Entities potentially regulated by the Ground Water Rule are public
water systems using ground water. Regulated categories and entities
include:
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Examples of regulated
Category entities
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Industry.................................. Public ground water systems.
State, Local, Tribal, or Federal Public ground water systems.
Governments.
------------------------------------------------------------------------
This table is not intended to be exhaustive, but rather provides a
guide for readers regarding entities likely to be regulated by this
action. This table lists the types of entities that EPA is now aware
could potentially be regulated by this action. Other types of entities
not listed in this table could also be regulated. To determine whether
your facility is regulated by this action, you should carefully examine
the applicability criteria in Sec. 141.400(b) of this proposed rule. If
you have questions regarding the applicability of this action to a
particular entity, consult the person listed in the preceding section
entitled FOR FURTHER INFORMATION CONTACT.
Abbreviations Used in This Notice
AWWA: American Water Works Association
ASDWA: Association of State Drinking Water Administrators
AWWARF: American Water Works Association Research Foundation
BMP: Best Management Practice
CDC: Centers for Disease Control and Prevention
CT: The residual concentration of disinfectant multiplied by the
contact time
CWS: community water system
CWSS: Community Water System Survey
DBP: disinfection byproducts
ELR: Environmental Law Reporter
EPA: Environmental Protection Agency
FR: Federal Register
GAO: Government Accounting Office
GWR: Ground Water Rule
GWS: ground water system
HAA5: Haloacetic acids consisting of the sum of mono-, di-, and
trichloroacetic acids, and mono-and dibromoacetic acids
HAV: Hepatitis A Virus
ICR: Information Collection Rule
IESWTR: Interim Enhanced Surface Water Treatment Rule
IT: UV irradiance multiplied by the contact time
m: meter
ml: milliliters
MCL: maximum contaminant level
MCLG: maximum contaminant level goal
mg/L: milligrams per liter
MPN: most probable number
MWCO: molecular weight cut-off
NCWS: non-community water system
NTNCWS: non-transient non-community water system
PCR: polymerase chain reaction
PWS: public water system
RO: reverse osmosis
RT-PCR: reverse-transcriptase, polymerase chain reaction
SBREFA: Small Business Regulatory Enforcement Fairness Act
SDWA: Safe Drinking Water Act
SDWIS: Safe Drinking Water Information System
Stage 1 DBPR: Stage 1 Disinfectants/Disinfection Byproducts Rule
Stage 2 DBPR: Stage 2 Disinfectants/Disinfection Byproducts Rule
SWAPP: Source Water Assessment and Protection Program
SWTR: Surface Water Treatment Rule
TCR: Total Coliform Rule
TNCWS: transient non-community water system
TTHM: total trihalomethanes
UIC: Underground Injection Control
USGS: United States Geological Survey
US EPA: United States Environmental Protection Agency
UV: ultraviolet radiation
WHP: Wellhead Protection
Table of Contents
I. Introduction and Background
A. Statutory Authority
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B. Existing Regulations
1. Total Coliform Rule
2. Surface Water Treatment Rule and Interim Enhanced Surface
Water Treatment Rule
3. Information Collection Rule
4. Stage 1 Disinfectants/Disinfection ByProducts Rule
5. Underground Injection Control Program
6. Source Water Assessment and Protection Program (SWAPP) and
the Wellhead Protection (WHP) Program
C. Industry Profile--Baseline Information
1. Definitions and Data Sources
2. Alternate Definition of ``Public Water System'' and the
Problem of Short-term Water Providers
3. Number and Size of Ground Water Systems
4. Location of Ground Water Systems
5. Ownership of Ground Water Systems
D. Effectiveness of Various Best Management Practices in Ground
Water Systems
1. EPA Report on State Ground Water Management Practices
2. ASDWA Analysis of BMPs for Community Ground Water Systems
3. EPA Report on Ground Water Disinfection and Protective
Practices
E. Outreach Activities
1. Public Meetings
2. Review and Comment of Preliminary Draft GWR Preamble
II. Public Health Risk
A. Introduction
B. Waterborne Disease Outbreak Data
C. Ground Water Occurrence Studies
1. Abbaszadegan et al. (1999) (AWWARF Study)
2. Lieberman et al. (1994, 1999) (EPA/AWWARF Study)
3. Missouri Ozark Aquifer Study #1
4. Missouri Ozark Aquifer Study #2
5. Missouri Alluvial Aquifer Study
6. Wisconsin Migrant Worker Camp Study
7. EPA Vulnerability Study
8. US-Mexico Border Study
9. Whittier, California, Coliphage Study
10. Oahu, Hawaii Study
11. New England Study
12. California Study
13. Three State PWS Study (Wisconsin, Maryland and Minnesota)
D. Health Effects of Waterborne Viral and Bacterial Pathogens
E. Risk Estimate
1. Baseline Risk Characterization
2. Summary of Basic Assumptions
3. Population Served by Untreated Ground Water Systems
4. Pathogens Modeled
5. Microbial Occurrence and Concentrations
6. Exposure to Potentially Contaminated Ground Water
7. Pathogenicity
8. Potential Illnesses
10. Request for Comments
F. Conclusion
III. Discussion of Proposed GWR Requirements
A. Sanitary Surveys
1. Overview and Purpose
2. General Accounting Office Sanitary Survey Investigation
3. ASDWA/EPA Guidance on Sanitary Surveys
4. Other Studies
5. Proposed Requirements
6. Reporting and Record Keeping Requirements
7. Request for Comments
B. Hydrogeologic Sensitivity Assessment
1. Overview and Purpose
2. Hydrogeologic Sensitivity
3. Hydrogeologic Barrier
4. Alternative Approaches to Hydrogeologic Sensitivity
Assessment
5. Proposed Requirements
6. Request for Comments
C. Cross Connection Control
D. Source Water Monitoring
1. Overview and Purpose
2. Indicators of Fecal Contamination
3. Proposed Requirements
4. Analytical Methods
5. Request for Comments
E. Treatment Techniques for Systems with Fecally Contaminated Source
Water or Uncorrected Significant Deficiencies
1. Overview and Purpose
2. Proposed Requirements
3. Public Notification
4. Request for Comments
IV. Implementation
V. Economic Analysis (Health Risk Reduction and Cost Analysis)
A. Overview
B. Quantifiable and Non-Quantifiable Costs
1. Total Annual Costs
2. System Costs
3. State costs
4. Non-Quantifiable Costs
C. Quantifiable and Non-Quantifiable Health and Non-Health Related
Benefits
1. Quantifiable Health Benefits
2. Non-quantifiable Health and Non-Health Related Benefits
D. Incremental Costs and Benefits
E. Impacts on Households
F. Cost Savings from Simultaneous Reduction of Co-Occurring
Contaminants
G. Risk Increases From Other Contaminants
H. Other Factors: Uncertainty in Risk, Benefits, and Cost Estimates
I. Benefit Cost Determination
J. Request for Comment
1. NTNC and TNC Flow Estimates
2. Mixed Systems
VI. Other Requirements
A. Regulatory Flexibility Act (RFA)
1. Background
2. Use of Alternative Definition
3. Initial Regulatory Flexibility Analysis
4. Small Entity Outreach and Small Business Advocacy Review
Panel
B. Paperwork Reduction Act
C. Unfunded Mandates Reform Act
1. Summary of UMRA Requirements
2. Written Statement for Rules With Federal Mandates of $100
Million or More
3. Impacts on Small Governments
D. National Technology Transfer and Advancement Act
1. Microbial Monitoring Methods
E. Executive Order 12866: Regulatory Planning and Review
F. Executive Order 12898: Environmental Justice
G. Executive Order 13045: Protection of Children from
Environmental Health Risks and Safety Risks
1. Risk of Viral Illness to Children and Pregnant Women
2. Full Analysis of the Microbial Risk Assessment
H. Consultations with the Science Advisory Board, National Drinking
Water Avisory Council, and the Secretary of Health and Human
Services
I. Executive Orders on Federalism
J. Executive Order 13084: Consultation and Coordination With Indian
Tribal Governments
K. Plain Language
VII. Public Comment Procedures
A. Deadlines for Comment
B. Where to Send Comment
C. Guidelines for Commenting
VIII. References
I. Introduction and Background
The purpose of this section is to provide background on existing
regulations that affect ground water systems and current state
practices.
A. Statutory Authority
This section discusses the Safe Drinking Water Act (SDWA)
requirements which EPA must meet in developing the Ground Water Rule
(GWR).
EPA has the responsibility to develop a GWR which not only
specifies the appropriate use of disinfection but, just as important,
addresses other components of ground water systems to ensure public
health protection. Section 1412(b)(8) states that EPA develop
regulations specifying the use of disinfectants for ground water
systems ``as necessary.'' Under these provisions, EPA has the
responsibility to develop a ground water rule which specifies the
appropriate use of disinfection, and, in addition, addresses other
components of ground water systems to ensure public health protection.
B. Existing Regulations
This section briefly describes the existing regulations that apply
to ground water systems. These rules are the baseline for developing
the GWR. The regulations that will be discussed include the Total
Coliform Rule (TCR)(US EPA, 1989a), Surface Water Treatment Rule
(SWTR)(US EPA, 1989b), Interim Enhanced Surface Water Treatment Rule
(IESWTR)(US EPA 1998d), Information Collection Rule (ICR)(US EPA,
1996b), Stage 1 Disinfectant/Disinfection Byproducts Rule (Stage 1
DBPR)(US EPA, 1998e), Underground Injection Control Program (US EPA,
1999g) and the Source Water Assessment and Protection Program/Wellhead
Protection Program.
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1. Total Coliform Rule
The Total Coliform Rule (TCR), promulgated on June 29, 1989 (54 FR
27544)(US EPA,1989a) covers all public water systems. The rule protects
public water supplies from disease-causing organisms (pathogens), and
it is the most important regulation applicable to drinking water from
ground water systems.
Total coliforms are a group of closely related bacteria that are
generally free-living in the environment, but are also normally present
in water contaminated with human and animal feces. They generally do
not cause disease (there are some exceptions). Specifically, coliforms
are used as a screen for fecal contamination, as well as to determine
the efficiency of treatment and the integrity of the water distribution
system. The presence of total coliforms in drinking water indicates
that the system is either fecally contaminated or vulnerable to fecal
contamination.
The TCR requires systems to monitor their distribution system for
total coliforms at a frequency that depends upon the number of people
served and whether the system is a community water system (CWS) or non-
community water system (NCWS). The monitoring frequency ranges from 480
samples per month for the largest systems to once annually for some of
the smallest systems. If a system has a total coliform-positive sample,
it must (1) test that sample for the presence of fecal coliform or E.
coli, (2) collect three repeat samples (four, if the system collects
one routine sample or fewer per month) within 24 hours and analyze them
for total coliforms (and then fecal coliform or E. coli, if positive),
and (3) collect at least five routine samples in the next month of
sampling regardless of system size.
Under the TCR, a system that collects 40 or more samples per month
(generally systems that serve more than 33,000 people) violates the
maximum contaminant level (MCL) for total coliforms if more than 5.0%
of the samples (routine + repeat) it collects per month are total
coliform-positive. A system that collects fewer than 40 samples per
month violates the MCL if two samples (routine or repeat samples)
during the month are total coliform-positive. For any size system, if
two consecutive total coliform-positive samples occur at a site during
a month, and one is also fecal coliform/E. coli-positive, the system
has an acute violation of the MCL, and must provide public notification
immediately. The presence of fecal coliforms or E. coli indicates that
recent fecal contamination is present in the drinking water.
The TCR also requires a sanitary survey every five years (ten years
for a protected, disinfected, ground water system) for every system
that takes fewer than five samples per month (the monitoring frequency
for systems serving 4,100 people or fewer, which is approximately 97%
of GWS). Other provisions of the TCR include criteria for invalidating
a positive or negative sample and a sample siting plan to ensure that
all parts of the distribution system are monitored over time.
2. Surface Water Treatment Rule and Interim Enhanced Surface Water
Treatment Rule
The Surface Water Treatment Rule, promulgated in June 29, 1989 (54
FR 27486)(40 CFR Part 141, Subpart H)(US EPA 1989b), covers all systems
that use surface water or ground water under the direct influence of
surface water. It is intended to protect against exposure to Giardia
lamblia, viruses, and Legionella, as well as many other pathogens. The
rule requires all such systems to reduce the level of Giardia by 99.9%
(3-log reduction) and viruses by 99.99% (4-log reduction). Under this
rule, all surface water systems must disinfect. The vast majority must
also filter, unless they meet certain EPA-specified filter avoidance
criteria that define high source water quality. More specifically, the
SWTR requires: (1) A 0.2 mg/L disinfectant residual entering the
distribution system, (2) maintenance of a detectable disinfectant
residual in all parts of the distribution system; (3) compliance with a
combined filter effluent performance standard for turbidity (i.e., for
rapid granular filters, 5 nephelometric turbidity units (NTU) maximum;
0.5 NTU maximum for 95% of measurements (taken every 4 hours) during a
month); and 4) watershed protection and other requirements for
unfiltered systems. The SWTR set a maximum contaminant level goal
(MCLG) of zero for Giardia, viruses, and Legionella. The MCLG is a non-
enforceable level based only on health effects.
On December 16, 1998, EPA promulgated the Interim Enhanced Surface
Water Treatment Rule (IESWTR) (63 FR 69478)(US EPA, 1998d). The IESWTR
covers all systems that use surface water, or ground water under the
direct influence of surface water, that serve 10,000 people or greater.
Key provisions include: a 2-log Cryptosporidium removal requirement for
filtered systems; strengthened combined filter effluent turbidity
performance standards (1 NTU maximum; 0.3 NTU maximum for 95% of
measurements during a month); individual filter turbidity provisions;
disinfection benchmark provisions to ensure continued levels of
microbial protection while facilities take the necessary steps to
comply with new disinfection byproduct (DBP) standards; inclusion of
Cryptosporidium in the definition of ground water under the direct
influence of surface water and in the watershed control requirements
for unfiltered public water systems; requirements for covers on new
finished water reservoirs; sanitary surveys for all surface water
systems regardless of size; and an MCLG of zero for Cryptosporidium. In
a parallel rulemaking, EPA has proposed a companion microbial
regulation for surface water systems serving less than 10,000 people,
the Long Term 1 Enhanced Surface Water Treatment Rule.
3. Information Collection Rule
The Information Collection Rule, promulgated on May 14, 1996 (61 FR
24368)(40 CFR part 141, Subpart M)(US EPA, 1996b), is a monitoring and
data reporting rule. The data and information provided by this rule
will support development of the Stage 2 Disinfection Byproducts Rule
and a related microbial rule, the Long Term 2 Enhanced SWTR, scheduled
for promulgation in May 2002.
The ICR applied to large water systems serving at least 100,000
people, and ground water systems serving at least 50,000 people. About
300 systems operating 500 treatment plants were involved. The ICR
required systems to collect source water samples, and in some cases
finished water samples, monthly for 18 months, and test them for
Giardia, Cryptosporidium, viruses, total coliforms, and either fecal
coliforms or E. coli. The ICR also required systems to determine the
concentrations of a range of disinfectant and disinfection byproducts
in different parts of the system. These disinfection byproducts form
when disinfectants used for pathogen control react with naturally
occurring total organic compounds (TOC) already present in source
water. Some of these byproducts are toxic or carcinogenic. The rule
also required systems to provide specified operating and engineering
data to EPA. The required 18 months of monitoring under the ICR ended
in December 1998.
As noted earlier, the only ground water systems affected by the ICR
were those that served at least 50,000 people. These systems had to
conduct treatment study applicability monitoring (by measuring TOC
levels) and, in some
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cases, studies to assess the effectiveness of granular activated carbon
or membranes to remove DBP precursors. In addition, ground water
systems serving at least 100,000 people had to obtain disinfectant and
DBP occurrence and treatment data. EPA is still processing the ICR
data, and has not used this information in developing the GWR.
4. Stage 1 Disinfectants/Disinfection Byproducts Rule
The Stage 1 Disinfectants/Disinfection Byproducts Rule (Stage 1
DBPR) (63 FR 69389; December 16, 1998) (US EPA, 1998e) sets maximum
residual disinfection level limits for chlorine, chloramines, and
chlorine dioxide, and MCLs for chlorite, bromate, and two groups of
disinfection byproducts: total trihalomethanes (TTHMs) and haloacetic
acids (HAA5). TTHMs consist of the sum of chloroform,
bromodichloromethane, dibromochloromethane, and bromoform. HAA5 consist
of the sum of mono-, di-, and trichloroacetic acids, and mono- and
dibromoacetic acids. The rule requires water systems that use surface
water or ground water to remove specified percentages of organic
materials, measured as total organic carbon (TOC), that may react with
disinfectants to form DBPs. Under the rule, precursor removal will be
achieved through a treatment technique (enhanced coagulation or
enhanced softening) unless a system meets alternative criteria.
The Stage 1 DBPR applies to all CWSs and non-transient NCWSs, both
surface water systems and ground water systems, that treat their water
with a chemical disinfectant for either primary or residual treatment.
In addition, certain requirements for chlorine dioxide apply to
transient water systems.
A ground water system that disinfects with chlorine or other
chemical disinfectant must comply with the Stage 1 DBPR by December
2003. Sampling frequency will depend upon the number of people served.
Ground water systems not under the direct influence of surface water
that serve 10,000 people or greater must take one sample per quarter
per treatment plant, and analyze for TTHMs and HAA5; systems that serve
fewer than 10,000 people must take one sample per year per treatment
plant during the month of warmest water temperature, and analyze for
the same chemicals. Systems must monitor for chlorine or chloramines at
the same location and time that they monitor for total coliforms.
Additional monitoring for other chemicals is required for systems that
use ozone or chlorine dioxide.
5. Underground Injection Control Program
In 1980, EPA established an Underground Injection Control (UIC)
Program (US EPA, 1999g) to prevent injection practices which
contaminate sources of drinking water. The UIC Program protects both
underground sources of drinking water and ground water under the direct
influence of surface water, which includes at least 41 percent of the
streams and rivers in the U.S. during dry periods. Injection is a
common and long-standing method of placing fluids underground for
disposal, storage, replenishment of ground water, enhanced recovery of
oil and gas, and mineral recovery. These fluids often contain
contaminants. The EPA sets minimum requirements for effective State
programs to ensure that injection practices, or ``injection wells'' as
they are called in the UIC Program, are operated safely. EPA or the
appropriate State regulatory agency may impose on any injection well,
requirements for siting, construction, corrective action, operation,
maintenance, monitoring, reporting, plugging and abandonment, and
impose penalties on violators. The UIC Program regulations are designed
to recognize varying geologic, hydrologic or historic conditions among
different States or areas within a State.
The UIC Program regulations are found under Title 40 of the Code of
Federal Regulations (CFR), Parts 124, and 144-148. Section 144.6
divides injection practices into five categories or classes of wells.
Classes I, II, and III are wells which inject fluids beneath and away
from aquifers used by ground water systems into confined geologic
formations. These wells are associated with municipal or industrial
waste disposal, hazardous waste or radioactive waste sites, oil and gas
production, and extraction of minerals. Class IV and most of Class V
are wells which inject contaminants, into or above aquifers which may
be used by ground water systems. Class IV wells inject hazardous or
highly radioactive wastes and are banned by all States and EPA. Class V
wells include storm water and agricultural drainage wells, dry wells,
floor drains and similar types of shallow disposal systems which
discharge directly or indirectly to ground water, but in any case, must
not endanger the ground water resources. However, Class V wells which
may pose the greatest potential threat to ground water systems include
poorly-designed or malfunctioning large-capacity septic tanks, leach
fields and cesspools associated with solely sanitary wastewater
disposal. Malfunctioning septic systems can result in the release of
disease-causing microorganisms including enteric viral and bacterial
pathogens to surface and ground water. Multi-family, commercial,
manufacturing, recreational, and municipal facilities, particularly
those located in unsewered areas sometimes dispose both sanitary waste
and process wastewater containing harmful chemicals in Class V wells.
This combination can increase the risk of contamination to aquifers
used by ground water systems. Approximately half of the States have
adopted primary enforcement authority for the regulation in whole or
part and, therefore, have primary enforcement responsibility (primacy).
State enforcement activities range from notices of improper activities
to penalties and well closures. For those States which do not have
primacy, the EPA Regional Offices perform the enforcement duties.
(Note: the UIC Program does not regulate individual or single family
residential septic systems and cesspools which inject solely sanitary
wastewater) (40 CFR 144.1(g)(1)(2)). EPA has finalized banning large
capacity cesspools in ground water source water protection areas (64 FR
234, December 7, 1999)(USEPA, 1999g).
6. Source Water Assessment and Protection Program (SWAPP) and the
Wellhead Protection (WHP) Program
The Wellhead Protection Program (WHP Program) in SDWA section 1428
requires every State to develop a program that protects ground water
sources of public drinking water. The intended result of the WHP
Program are local pollution prevention programs that reduce or
eliminate the threats of contamination to ground water sources of
drinking water. To do this, States delineate wellhead protection areas
(WHPA) in which sources of contamination are managed to minimize ground
water contamination. WHPA boundaries are determined based on factors
such as well pumping rates, time-of-travel of ground water flowing to
the well, aquifer boundaries, and degree of aquifer protection by the
overlying geology. These hydrogeologic characteristics have a direct
effect on the likelihood and extent of contamination. Currently, 48
States and two territories have a WHP Program in place.
A new Source Water Assessment and Protection Program (SWAPP) was
incorporated into SDWA section 1453 and requires each State to
establish a SWAPP that describes how the State will: (1) Delineate
source water
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protection areas; (2) inventory significant contaminants in these
areas; and (3) determine the susceptibility of each public water supply
to contamination. This program builds upon the WHP Program; however, it
addresses both ground water and surface water sources of public
drinking water. The States' SWAPP were approved by EPA by November,
1999. Under the SWAPP, the State must complete source water assessments
for all PWSs by November 6, 2001, although EPA may grant an extension
to May 6, 2003. A summary of the results of the source water
assessments must then be made available to the public in CWSs' Consumer
Confidence Reports. The 1996 Amendments to the SDWA do not require
States to protect water sources after the assessments are completed.
EPA seeks, in today's proposed GWR, to incorporate the States'
SWAPP and WHP Programs into an overall Agency program for protecting
ground water sources of public drinking water by encouraging States to
use information gathered through these programs in site-specific
sanitary surveys and hydrogeologic sensitivity assessments where
appropriate.
C. Industry Profile--Baseline Information
1. Definitions and Data Sources
Outlined in the following section are data sources relied upon by
the Agency to develop baseline information for the GWR. The baseline
information is important to understanding how various regulatory
options might affect risk reduction and the cost to small public water
systems. The information shows that there is a large number of systems
which solely utilize ground water, over 156,000. In addition, most of
the ground water systems are small, with 97% serving 3,300 or fewer
people. However, 55% of the people served by ground water sources get
their drinking water from systems which serve 10,000 or more persons
(one percent of the systems).
A public water system (PWS) is one that serves 25 or more people or
has 15 or more service connections and operates at least 60 days per
year. The following discussion of PWSs is based on the current
definition of PWS (i.e., operating at least 60 days a year). A PWS can
be publicly owned or privately owned. EPA classifies PWSs as community
water systems (CWSs) or non-community water systems (NCWSs). CWSs are
those that serve at least 15 service connections used by year-round
residents or regularly serves at least 25 year-round residents. NCWSs
do not have year-round residents, but serve at least 15 service
connections used by travelers or intermittent users for at least 60
days each year, or serving an average of 25 individuals for at least 60
days a year. NCWSs are further classified as either transient or non-
transient. A non-transient non-community water system (NTNCWS) serves
at least 25 of the same persons over six months per year (e.g.,
factories and schools with their own water source). Transient non-
community water systems (TNCWS) do not serve at least 25 of the same
persons over six months per year (e.g., many restaurants, rest stops,
parks). The majority of ground water systems are NCWSs, with 60%
(93,618) transient and 12% (19,322) non-transient. CWSs make up the
remaining 28% (44,910) of all ground water systems. Although there are
far more NCWSs, CWSs serve a far larger number of people.
Over 88 million people are served by CWSs that use ground water and
20 million people are served by NCWSs that use ground water. An overlap
occurs because most people are served by both types of systems which
may also include a combination of ground and surface water. For
example, a person may be served by a surface water community water
system (CWS) at home and by a ground water non-community water system
(NCWS) at work.
EPA uses two primary sources of information to characterize the
universe of ground water systems: the Safe Drinking Water Information
System (SDWIS) and the Community Water System Survey (CWSS) (US EPA,
1997c). EPA's SDWIS contains data on all PWSs as reported by States and
EPA Regions. This data reflects both mandatory and optional reporting
components. States must report the location of the system, system type
(CWS, TNCWS, or NTNCWS), primary raw water source (ground water,
surface water or ground water under the direct influence of surface
water), and violations. States may also report, at their option, type
of treatment and ownership type. EPA does not have complete data on the
discretionary items (such as treatment) in SDWIS for every system; this
is especially common for NCWSs.
The second source of information, CWSS, is a detailed survey of
surface and ground water CWSs conducted by EPA in 1995 (US EPA, 1997c).
The CWSS includes information such as the number of system operators,
revenues, expenses, treatment practices, source water protection
measures, and capacity (i.e., the amount of water the system is
designed to deliver). The CWSS contains data from 1,980 water systems,
and is stratified to represent CWSs across the U.S. Of the 1,980 water
systems that were surveyed by CWSS, 1,020 are ground water systems; 510
are surface water systems; and 450 represent purchased water systems.
Among the ground water systems represented, approximately 17% were from
systems serving 100 persons or less; 20% were from systems serving 101-
500 persons; 13% were from systems serving 501-1,000 persons; 14% were
from systems serving 1,001-3,300 persons; 15% were from systems serving
3,301-10,000 persons; 10% were from systems serving 10,001-50,000
persons; and 11% were from systems serving 50,001 or more persons.
Baseline profile data for ground water systems from SDWIS and CWSS
are summarized later. The data on system ownership, treatment, and
operator information is from the CWSS.
2. Alternate Definition of ``Public Water System'' and the Problem of
Short-Term Water Providers
EPA is not today proposing to change the definition of ``public
water supply,'' nor proposing additional requirements for short-term
water providers. If EPA decides to take either action, EPA will publish
a proposal at a later date. However, EPA requests comment on the
following issues.
A PWS is one that serves 25 or more people or has 15 or more
service connections and operates at least 60 days per year. EPA
requests comment on the definition of ``public water system''
specifically, shortening the time period within the regulatory
definition (Sec. 141.2). Section 1401(4)(A) of the SDWA defines public
water system as one that ``regularly serves at least twenty-five
individuals.'' EPA by regulation defined the minimum time period that a
system ``regularly'' serves as 60 days. See 40 FR 59566, December 24,
1975 for a discussion of the definition. The current definition applies
after a minimum of 1,500 consumer servings (60 days multiplied by 25
individuals). However, some drinking water providers serve far more
people during just a few events. For example, out-door public events
may occur at a site just a few days a year but may draw thousands of
people to each event. Such drinking water providers thus can affect the
public health of a similar number of persons in a short period of time
as a system that serves fewer people for a longer period. EPA wants to
provide the same public health protection in these situations. Only
[[Page 30199]]
contaminants that cause adverse health effects through small volumes or
short exposure (e.g., acute contaminants such as microbes, nitrate and
nitrite) are of concern at these short term events. Therefore, EPA is
considering changing the definition of ``public water system'' by
reducing the 60 day time frame to 30 days and including events drawing
many people on one or just a few days, specifically by adding the
phrase, ``or serves at least 750 people for one or more days'' to the
end of the current definition of ``public water system.'' In other
words, for short-term providers, the term ``regularly serves'' would be
defined in terms of the number of persons served rather than days of
service, but the minimum number of persons served would be equivalent
to the number of servings for longer-term systems. EPA requests comment
on this issue. Rather than the simple total of 750 (30 days times 25
people), should EPA include a minimum of persons served days
(calculated by multiplying the average number of individuals served by
the number of days the system serves water)? What should that number
be? Should there be a sliding scale (e.g., for a system operating one
day and serving more than 10,000 consumers, and systems operating more
than 30 days and serving 2,000 consumers)? EPA requests comments on
defining/identifying systems, implementation, public notice, training,
monitoring and record keeping and reporting issues for these systems if
they were included.
As an alternate to changing the definition EPA is also considering
and requesting comments on requiring under section 1431 of the SDWA or
other appropriate authorities that transient water providers or other
types of drinking water systems (including those not currently defined
as public water systems) monitor for acute contaminants prior to
providing water to the public and requiring that any such provider that
finds acute contaminants at a level above the MCL not be allowed to
serve drinking water until it is corrected. Currently, transient public
water systems must currently monitor for total coliforms, nitrate and
nitrite. In addition, transient public water systems using surface
water or ground water under the direct influence of surface water must
comply with the treatment technique requirements of the SWTR. EPA is
also considering proposing requiring any non-community water system
that is not operated year round monitor for: fecal coliforms, nitrate
and nitrate, and that monitoring required to show treatment technique
compliance (e.g., Cryptosporidium) no more than 30 days prior to
beginning operation for that season. EPA requests comment on what time
frame the monitoring should be completed prior to beginning operation
(i.e., 10 or 15 days).
3. Number and Size of Ground Water Systems
Nationally, SDWIS indicates that there are approximately157,000
public water systems that use ground water solely (SDWIS, 1997).
Slightly more than 13,000 additional systems use surface water. SDWIS
only describes any system that uses any amount of surface water as a
surface water system. SDWIS therefore, does not have information on the
number of systems that mix ground water and surface water. Under the
SDWA and for purposes of the Regulatory Flexibility Act (RFA) analysis,
EPA defines a small system as serving fewer than 10,000 people.
According to SDWIS (1997), 96.6% of the 42,413 CWSs and virtually all
of the NCWSs that use ground water serve fewer than 10,000 persons and
thus are ``small.'' Collectively, 99% of systems serve fewer than
10,000 people. About 97% of the systems (152,555) serve 3,300 people or
fewer (totaling over 31 million people nationally). The purpose of
these requirements would be to prevent any endangerment to public
health that might occur if these short-term, high volume providers
dispense drinking water that is untested and potentially contaminated.
4. Location of Ground Water Systems
Ground water systems are located in all 50 States, many tribal
lands and most United States territories. The number of ground water
systems varies substantially by State. The largest numbers of ground
water systems are in the States of Wisconsin, Michigan, Pennsylvania,
New York and Minnesota. These five States, each with over 8,000 ground
water systems, account for over 50,698 ground water systems--one third
of the total number in the U.S. By contrast, Hawaii (126), Kentucky
(287), Rhode Island (430), and the United States territories (254) have
the fewest ground water systems (See Table I-1).
5. Ownership of Ground Water Systems
For ground water CWSs, 36% are publicly operated, 35% are owned and
operated by private entities whose primary business is providing
drinking water, and 29% are ancillary water systems which are operated
by entities whose primary business is not providing drinking water, but
do so to support their primary business (e.g., mobile home park
operators). The distribution of ownership type, however, varies
significantly with the size of the system. For example, over 90% of the
ground water systems serving less than 100 people are privately owned
or are ancillary systems. For systems serving over 100,000 people, only
16% are privately owned and none are ancillary systems.
Table I-1.--Number of Ground Water Systems and Populations Served by State and System Type
--------------------------------------------------------------------------------------------------------------------------------------------------------
CWSs TNCWSs NTNCWSs
--------------------------------------------------------------------------------------
State/territory Number of Population Number of Population Number of Population
systems served systems served systems served
--------------------------------------------------------------------------------------------------------------------------------------------------------
Alabama.......................................................... 345 1,283,469 123 11,170 46 21,182
Alaska........................................................... 511 342,722 906 97,647 0 0
American Samoa................................................... 10 48,692 0 0 0 0
Arizona.......................................................... 783 1,308,843 602 120,126 216 100,317
Arkansas......................................................... 480 1,003,145 442 22,521 57 13,528
California....................................................... 2,831 14,223,977 3,698 1,301,671 1,018 359,096
Colorado......................................................... 548 927,917 1,061 153,454 133 34,884
Commonwealth of the Northern Marianas............................ 30 50,769 7 620 6 3,039
Connecticut...................................................... 537 311,771 3,360 2,980,181 641 121,664
Delaware......................................................... 225 173,460 215 57,634 86 24,840
District of Columbia............................................. 0 0 0 0 0 0
Florida.......................................................... 2,019 13,132,468 3,660 304,865 1,119 286,055
Georgia.......................................................... 1,465 1,484,860 663 127,661 291 80,240
Guam............................................................. 6 20,220 0 0 2 770
[[Page 30200]]
Hawaii........................................................... 109 1,247,315 3 1,125 14 7,437
Idaho............................................................ 658 579,778 1,033 125,873 265 68,195
Illinois......................................................... 1,255 2,606,104 3,715 413,000 446 142,655
Indiana.......................................................... 806 1,826,820 2,984 327,229 693 158,102
Iowa............................................................. 1,033 1,239,902 639 78,653 133 35,715
Kansas........................................................... 601 747,169 110 4,481 67 23,602
Kentucky......................................................... 124 271,630 83 9,374 80 21,620
Louisiana........................................................ 1,211 2,707,805 482 115,804 234 88,070
Maryland......................................................... 448 519,289 2,509 93,757 495 142,171
Massachusetts.................................................... 360 1,396,430 863 209,476 229 67,650
Michigan......................................................... 1,185 1,602,792 8,930 1,187,331 1,718 344,654
Minnesota........................................................ 919 2,074,843 6,963 252,602 672 49,514
Mississippi...................................................... 1,253 2,586,680 169 28,006 126 89,416
Missouri......................................................... 1,194 1,638,152 1,040 138,894 227 76,360
Montana.......................................................... 554 267,597 1,011 140,745 215 38,504
Nebraska......................................................... 616 811,112 584 22,241 189 26,219
Nevada........................................................... 250 187,509 273 55,792 91 28,497
New Hampshire.................................................... 621 262,371 1,012 181,949 421 77,505
New Jersey....................................................... 516 2,339,500 2,955 346,484 1,009 274,758
New Mexico....................................................... 600 1,235,920 506 74,256 149 38,101
New York......................................................... 1,940 4,396,557 5,742 853,533 693 248,223
North Carolina................................................... 1,900 1,271,804 5,373 542,400 655 198,136
North Dakota..................................................... 258 239,874 215 16,910 22 2,349
Ohio............................................................. 1,129 3,555,876 3,545 533,921 1,116 276,441
Oklahoma......................................................... 556 671,287 302 34,172 123 20,419
Oregon........................................................... 677 622,157 1,390 233,477 332 67,531
Pennsylvania..................................................... 1,788 1,567,696 7,017 922,336 1,251 480,328
Puerto Rico...................................................... 207 623,958 4 765 43 36,426
Rhode Island..................................................... 59 127,854 300 48,875 71 25,246
South Carolina................................................... 550 671,878 577 54,837 248 71,239
South Dakota..................................................... 367 250,742 243 42,949 25 3,072
Tennessee........................................................ 193 1,312,996 503 61,504 58 11,010
Texas............................................................ 3,613 6,150,001 1,378 245,171 748 253,468
Tribes........................................................... 685 330,466 0 0 82 20,833
Utah............................................................. 335 583,506 439 79,371 52 20,969
U.S. Virgin Islands.............................................. 0 0 0 0 0 0
Vermont.......................................................... 346 154,521 718 523,079 1 25
Virginia......................................................... 1,199 584,779 1,911 443,920 772 312,422
Washington....................................................... 2,092 2,299,340 1,498 283,735 287 70,009
West Virginia.................................................... 297 304,888 644 47,313 182 39,318
Wisconsin........................................................ 1,117 1,947,016 9,704 731,781 1,049 214,561
--------------------------------------------------------------------------------------------------------------------------------------------------------
D. Effectiveness of Various Best Management Practices in Ground Water
Systems
There are numerous sanitation practices, called best management
practices (BMPs), to prevent, identify and correct contamination in a
water supply. These practices relate to well siting, well construction,
distribution system design and operations. Examples of BMPs that form a
barrier to ground water contamination include drilling into a protected
aquifer; siting a well away from sources of contamination; identifying
and controlling contamination sources; and disinfection. BMPs that form
a barrier to well contamination include well casing, well seals, and
grouting the well. Distribution system BMPs include disinfection;
maintaining positive pressure; flushing water mains; and adopting cross
connection control programs. Surveillance BMPs such as sanitary surveys
are conducted to identify weaknesses in the barriers.
EPA recognizes that BMPs can and do contribute significantly to the
safety of drinking water; however, the effectiveness of each individual
practice can be difficult to measure. Two studies, State Ground Water
Management Practices--Which Practices are Linked to Significantly Lower
Rates of Total Coliform Rule Violations? (US EPA, 1997d) and the
Analysis of Best Management Practices for Community Ground Water
Systems (Association of State Drinking Water Administrators, or ASDWA,
1998), were conducted to examine the relative effectiveness of BMPs in
reducing microbial contamination of ground water systems. The EPA study
compared BMP implementation at the State level to total coliform MCL
violation rates of community ground water systems over a four year
period. The ASDWA study compared BMP implementation to detections of
both total and fecal coliform in community ground water systems over a
two year period.
A third study was conducted by EPA, Ground Water Disinfection and
Protective Practices in the United States, (US EPA, 1996a) to review
State practices and requirements for the protection of drinking water
that has ground water as its source.
1. EPA Report on State Ground Water Management Practices
In the EPA study, State Ground Water Management Practices--Which
[[Page 30201]]
Practices are Linked to Significantly Lower Rates of Total Coliform
Rule Violations? (US EPA, 1997d), 12 BMPs were compared to the MCL
violation rate for total coliform in community water systems by State.
The 12 State BMPs were taken from the EPA report Ground Water
Disinfection and Protective Practices in the United States (US EPA,
1996a). The study used total coliform MCL violation data in SDWIS for
community water systems for Fiscal Years 1993 through 1996. In the
study, pairwise and stepwise linear regression analyses were used to
determine if there was a statistically significant difference in the
TCR MCL violation rates between those States that practice a particular
BMP and those that do not. From this perspective, BMPs associated with
lower violation rates are considered effective. The 12 BMPs included in
the study were well construction codes, well/pump disinfection
requirements, sanitary surveys, disinfection of new/repaired mains,
cross connection controls, operator certification, minimum setback
distances, EPA approved State Wellhead Protection Programs, periodic
flushing of mains, wellhead monitoring, hydrogeologic criteria, and
disinfection.
Six of the 12 State management practices were unsuitable for
pairwise analysis because these practices were present in nearly all
States. Therefore, a comparison of TCR MCL violation rates in States
with and without these practices could not be made. The BMPs for which
analysis were not done were: well construction codes, well/pump
disinfection requirements, sanitary surveys, disinfection of new/
required mains, cross connection controls, and operator certification.
However, these six management practices were evaluated as part of the
1998 Best Management Practices Survey conducted by ASDWA.
Using a pairwise statistical analysis, two of the remaining six
practices, disinfection and hydrogeologic criteria, showed a
significant statistical relationship (at a .01 and a .05 level of
confidence, respectively) in lowering the statewide median TCR
violation rates, with disinfection showing the strongest relationship.
In this analysis, disinfection is defined as the maintenance of at
least a chlorine residual or its equivalent at the entry point or in
the distribution system. The report focused its analysis on
disinfection practices among 20 States, comparing the 10 highest
disinfecting States with the 10 lowest disinfection States.
Specifically, the 10 States with the highest percentage of disinfected
CWSs had an average MCL violation rate of 16% over the four year
period, versus a 33% violation rate for the ten States with the lowest
disinfection rates. States that require hydrogeologic criteria for well
siting and construction decisions had significantly lower median MCL
violation rates than States that do not use these criteria (15.4% vs.
24.6%). The other four practices, minimum setback distances from
pollution sources, EPA approved Wellhead Protection Programs, periodic
flushing of the distribution system, and wellhead monitoring, did not
show a significant relationship in lowering TCR violation rates at the
State level. The report does not provide information on the statistical
significance of these results.
The four year time frame for the statistical analyses was chosen as
a more accurate reflection of the effectiveness of statewide management
practices given the high degree of variability in the TCR violation
rate from year to year. Different trends emerge when annual rates are
compared. There is not enough data to determine if the year to year
variability, shown in the FY 96 data, correlates to a change in State
management practices.
In a second analysis, stepwise linear regression was used on the
six best management practices to further explain the variability among
States in their reported TCR MCL violation rates. This analysis
examines both the simultaneous effect of several BMPs on the State TCR
MCL violation rate and evaluates which of the practices may explain the
variability in the TCR violation rate among States. Ascertaining how
much of the State-to-State variability can be explained by each of the
practices is an important question given that the TCR requirements are
the same for all States. The results of this analysis indicate that
disinfection is the single largest factor in explaining the difference
in the TCR violation rate among States. In general, the higher the rate
of disinfection, the lower the rate of TCR MCL violations.
Uncertainties associated with this analysis were: (1) Whether a
State's BMP requirements are fully implemented at the system level; (2)
what effect the six State BMPs not analyzed had on violation rates; (3)
the degree of voluntary implementation of BMPs; and (4) the effect of
not including State practices required only under certain
circumstances. Nonetheless, this data on State management practices
indicates that there is a significant association between disinfection
and a lower TCR MCL violation rate.
2. ASDWA Analysis of BMPs for Community Ground Water Systems
In the ASDWA study, The Analysis of Best Management Practices for
Community Ground Water Systems (ASDWA, 1998), a working group selected
28 BMPs that represent four major areas of plant operations and
developed and distributed a survey to all 50 State drinking water
programs. Each State was asked to select eight systems in each of the
three following categories: (1) Systems with no detections of total
coliform; (2) systems with total coliform detections only; and (3)
systems with both total coliform and fecal coliform (or E. coli)
detections. For each system, the State was asked to report which of 28
BMPs listed were used by the system during a two year period (1995 and
1996). Thirty-six States responded to the survey, each completing up to
24 individual system surveys, providing data for 812 systems.
The survey results were analyzed using both descriptive statistics
and two statistical models--pairwise and logistical regression. The
descriptive statistics illustrate the characteristics of a system but
cannot isolate the effect of a particular BMP from the effects of other
BMPs. The statistical models were used to describe the relationship
between implementation of individual or a group of BMPs and a reduction
in total or fecal coliform detections.
A pairwise association analysis (i.e., comparing a system that
implements a particular BMP to one that does not) was used to determine
if the use of a BMP reduced the percentage of positive total coliform
samples. The analysis determined that a significant association was
found between 21 of the 28 BMPs and systems with no total coliform
detections. The two BMPs with the strongest correlation to fewer total
coliform detections were correction of deficiencies identified by the
sanitary survey and operator certification (ASDWA, 1998).
Using pairwise analysis for systems with fecal coliform (based only
on those systems with at least one positive total coliform sample), the
study found a significant association for eight of the twenty-eight
BMPs. These eight BMPs include: system wells constructed according to
State regulations, routine disinfection after well or pump repair,
treatment for purposes other than disinfection, system maintaining
acceptable pressure at all times, water distribution tanks are designed
according to State requirements, systems are in compliance with State
permitting requirements, systems have corrected deficiencies noted by
the State
[[Page 30202]]
and system and operators receive routine training and education.
According to the results, fewer BMPs are found to be significant in
this analysis than the total coliform analysis. These results are
expected given that the analysis of fecal coliform and E. coli only
evaluate systems with at least one total coliform positive detection.
Fecal coliform and E. coli tests are more specific to organisms found
in human and animal feces, whereas total coliform tests indicate the
presence of a broader class of enteric organisms. For this reason,
there are fewer data points to model the association of BMPs with fecal
coliform. Therefore, this analysis sets apart only the BMPs significant
in preventing or eliminating fecal contamination.
Using the logistical regression technique, three BMPs were
associated with a significant reduction of total coliform-positive
samples: (1) Maintaining a disinfectant residual; (2) operator
training; and (3) correcting deficiencies identified by the State as
part of a sanitary survey. The two BMPs associated with a significant
reduction of fecal coliform/E. coli-positive samples were treatment for
purposes other than disinfection, e.g., iron removal, and operator
training. Another analysis was constructed using Logit models for four
categories of BMPs to consider the effects of BMPs in groups rather
than individually. Out of the four categories (Source Protection/
Construction, Treatment, Distribution System, and Management and
Oversight), the Management and Oversight category showed the most
significant association with reduced coliform detections.
The ASDWA survey also evaluated the effectiveness of BMPs with
regard to system size. For systems serving less than 500 persons,
correction of deficiencies identified by the State, and regular
training and education of operators were the most significant in
reducing microbial contamination. Routine disinfection after well or
pump repair had the greatest significance among systems serving between
501 and 3,300 persons, while maintaining a disinfection residual had
the greatest significance among systems serving between 3301 and 10,000
persons.
Overall, this study found that the percentage of systems
implementing BMPs is highest among systems with no total coliform
detections. In addition, systems that routinely educate and train their
operators were more likely to implement other BMPs than systems with no
regular training. Similarly, those systems that practice disinfection
(contact time or maintain disinfection residual) were more likely to
implement other BMPs than systems that do not disinfect. Observations
about the implementation of BMPs suggests that many BMPs are
interrelated, therefore, it is difficult to isolate the effect of an
individual BMP.
3. EPA Report on Ground Water Disinfection and Protective Practices
The purpose of the EPA study, Ground Water Disinfection and
Protective Practices in the United States, (US EPA, 1996a) was to
compile and assess State regulations, guidance, codes, and other
materials pertaining to protection of public health from microbial
contamination in public water systems using ground water.
The information compiled included the following:
Wellhead/ground water protection information;
Ground water disinfection requirements;
Well siting and construction requirements/guidelines;
Sanitary survey requirements/guidelines;
Distribution system protection requirements/guidelines;
and
Operator certification requirements.
The study found that there are widespread, but diverse requirements
for the protection of drinking water that has ground water as its
source. Few of these protective practices are used by all States and
there is a variety of interpretations of the same practice. For
example, 47 States specify minimum setback distances from sources of
microbial contamination but show a wide range of setback distances for
the same type of contaminant source; 49 States drinking water programs
require disinfection of some sort, but when and where disinfection is
required varies considerably; and of the 48 States that have well
construction codes, 21 States do not require consideration of
hydrogeological criteria in the approval of the siting of a well.
Overall, the study found that although many States appear to
require similar BMPs, the nature, scope, and detail of these
requirements varies considerably at the national level.
E. Outreach Activities
1. Public Meetings
As part of the 1986 amendments to the Safe Drinking Water Act
(SDWA) Section 1412(b)(8), Congress directed EPA to promulgate a
national primary drinking water regulation (NPDWR) requiring
disinfection as a treatment technique for all public water systems,
including those served by surface water and ground water. In 1987, EPA
began developing a rule to cover ground water systems. This effort
included a preliminary public meeting on the issues in 1990 (see 55 FR
21093, May 22, 1990, US EPA, 1990a). In 1992, EPA circulated a strawman
draft for comment (see 57 FR 33960, July 31, 1992) (US EPA, 1992a).
From 1990 to 1997, EPA conducted technical discussions on a number
of issues, primarily to establish a reasonable means of establishing
whether a ground water source was vulnerable to fecal contamination and
thus pathogens. This effort was accomplished through ad hoc working
groups during more than 50 conference calls with participation of EPA
Headquarters, EPA Regional offices, States, local governments,
academicians, and trade associations. In addition, technical meetings
were held in Irvine, California in July 1996, (US EPA, 1996c) and in
Austin, Texas in March 1997 (US EPA, 1997e).
The SDWA was amended in August 1996, and as a result, several
statutory provisions were added establishing new drinking water
requirements. Specifically, Congress required under section 1412(b)(8)
that EPA develop regulations specifying the use of disinfectants for
ground water systems ``as necessary.'' These amendments established a
new regulatory framework that required EPA to set criteria for States
to determine whether ground water systems need to disinfect. In
December 1997, EPA held its first of a series of stakeholder meetings
to present a summary of the findings resulting both from technical
discussions held since 1990 and from information generated by internal
EPA working groups with the intention of developing disinfection
criteria for ground water systems.
EPA held a preliminary Ground Water Rule meeting on December 18 and
19, 1997, in Washington, DC for the purpose of engaging all interested
stakeholders in the analysis of data to support the GWR. The two day
meeting covered discussions on the implications of the data, solicited
further data from stakeholders, and reviewed EPA's next steps for rule
development, data analysis and stakeholder involvement.
Since December 1997, EPA has held GWR stakeholder meetings in
Portland, OR, Madison, WI, Dallas, TX, Lincoln, NE, and Washington, DC
along with three early involvement meetings with State representatives.
In addition, EPA has received valuable input from small system
operators as part of an Agency outreach initiative under the Small
Business Regulatory Enforcement Fairness Act. See section VI for more
[[Page 30203]]
information on the SBREFA process. Taken together, these stakeholder
meetings have been crucial both in obtaining feedback and getting
additional information as well as in guiding the Agency's consideration
and development of different regulatory components.
The Agency's goal in developing the GWR is to reduce the risk of
illness caused by microbial contamination in public water systems
relying on ground water. The series of GWR stakeholder meetings were
beneficial in assisting EPA in understanding how State strategies fit
together as part of a national strategy. For more information see the
(Stakeholders Meeting Summary, Resolve, July 27, 1998).
Portland, OR, GWR Stakeholder Meeting
There were four different regulatory approaches presented in the
first of a series of stakeholder meetings held in Portland, OR, in May
1998: the Barrier Assessment Approach, the Existing State Practices
Approach, the Setback Approach, and the Checklist Approach (Stakeholder
Meetings Summary, Resolve, July 27, 1998). All approaches address, to
varying degrees, three main areas: minimum program requirements or
baseline measures, identification of high risk wells, and corrective
action. Discussions on the potential approaches centered around
determining triggers that could place a well in a high priority
category and which minimum set of BMPs should be implemented at high
risk wells.
Madison, WI GWR Stakeholder Meeting
There were three approaches presented in a June 9, 1998, GWR
stakeholder meeting held in Madison, WI: Status Quo Approach, Baseline
Approach, and Disinfection Approach. Regulatory approaches were revised
in response to stakeholder input from the earlier GWR stakeholder
meetings, representing a continuum of requirements, from Existing
Status Quo to mandatory disinfection for all ground water systems. EPA
emphasized that existing occurrence data does not appear to support
mandatory disinfection across the board, but that the Agency would
still appreciate stakeholder input on a range of options. The
approaches presented were based on monitoring, inspections, BMPs and
disinfection.
Dallas, TX GWR Stakeholder Meeting
A third GWR meeting on June 25, 1998 in Dallas, TX, provided slight
modifications to the regulatory approaches, but for the most part the
regulatory approach remained unchanged from the Madison meeting held in
early June. EPA continued to emphasize the need to identify and
strengthen the potential barriers to contamination. Among the three
approaches, (Status Quo, Progressive and Universal Disinfection) the
Progressive approach was considered the more viable regulatory option
to ensure public health protection among public water systems.
Early Involvement Meetings
ASDWA held three early involvement meetings (EIMs) on the GWR. The
first EIM followed the May 5, 1998 stakeholder meeting in Portland, OR.
The second EIM meeting was held in Washington, DC on July 14 and 15,
1998 and the third meeting was held in Chicago, IL on April 7 and 8,
1999. Representatives from 12 States, four EPA Regions, ASDWA and EPA
Headquarters participated in the May 6 and 7, 1998 meeting in Portland,
OR. The second EIM involved 10 State representatives, ASDWA, and EPA
Headquarters. The third EIM included one Region, seven State
representatives, ASDWA and EPA Headquarters. The purpose of the
meetings was to review the findings and comments from the stakeholder
meetings and to work together to further refine GWR regulatory options.
EPA and States discussed a range of issues including risk, exposure,
strategies for identifying high risk systems, occurrence data, and
regulatory implementation barriers.
2. Review and Comment of Preliminary Draft GWR Preamble
EPA developed a preliminary draft preamble reflecting a wide range
of input from numerous stakeholders across the country including four
public meetings, three EIMs with State representatives, in addition to
valuable input received from small system operators as part of the
outreach process established by SBREFA.
To facilitate the rule development process, the preliminary draft
preamble was made available to the public via the Internet through
EPA's website site on February 3, 1999. Approximately 300 copies were
mailed to participants of the public meetings or to those who requested
a copy. EPA welcomed any comments, suggestions, or concerns reviewers
had on either the general direction or the technical basis of the
proposal. EPA closed the email box on February 23, 1999 and continued
to receive written comments through the mail through March 17, 1999.
Because this was an informal process, EPA did not prepare a formal
response to the comments. Nonetheless, the Agency carefully reviewed
and evaluated all comments and technical suggestions and greatly
appreciated the input and feedback provided by these outreach efforts.
Eighty individual comment letters were received. Commenters
included: State and local government representatives, trade
associations, academic institutions, businesses and other Federal
agencies. Microbial monitoring received the most individual comments.
Sanitary survey, sensitivity assessment and treatment issues were next,
respectively.
II. Public Health Risk
The purpose of this section is to discuss the health risk
associated with pathogens in ground waters. More detailed information
about pathogens may be found in three EPA drinking water criteria
documents for viruses (US EPA 1985a; 1999b; 1999c), three EPA criteria
documents for bacteria (US EPA 1984a, b; 1985b) and the GWR Occurrence
and Monitoring Document (US EPA, 1999d). EPA requests comment on all
the information presented in this section, and the potential impact of
proposed regulatory provisions on public health risk.
A. Introduction
Enteric viral and bacterial pathogens are excreted in the feces of
infected individuals. Many bacterial pathogens can infect both humans
and animals. Bacterial pathogens that infect humans can also be found
in animal feces. In contrast, enteric viruses that are human pathogens
generally only infect humans, and thus are only found in human feces.
These organisms are able to survive in sewage and leachate derived from
septic tanks (septage) and sewer lines. When sewage and septage are
released into the environment, they are a source of fecal
contamination. Fecal contamination is a very general term that includes
all of the organisms found in feces, both pathogenic and non-
pathogenic, as well as chemicals.
Fecal contamination of ground water can occur by several routes.
First, fecal contamination can reach the ground water source from
failed septic systems, leaking sewer lines, and from land discharge by
passage through soils and fissures. Twenty-five million households in
the United States use conventional onsite wastewater treatment systems,
according to the 1990 Census. These systems include systems with septic
systems and leach fields. A national estimate for failure rates of
these systems is not available; however, a National Small Flows
Clearinghouse survey reports that in
[[Page 30204]]
1993 alone, 90,632 failures were reported. (USEPA, 1997f). The volume
of septic tank waste, alone, that is released into the subsurface has
been estimated at one trillion gallons per year (Canter and Knox,
1984). This contamination may eventually reach the intake zone of a
drinking water well. Second, fecal contamination from the surface may
enter a drinking water well along the casing or through cracks in the
sanitary seal if it is not properly constructed, protected, or
maintained. Third, fecal contamination may also enter the distribution
system when cross connection controls fail or when negative pressure in
a leaking pipe allows contaminant infiltration.
Biofilms in distribution systems may harbor bacterial pathogens,
especially the opportunistic pathogens that cause illness primarily in
individuals with weakened immune systems. These bacterial pathogens may
have entered the distribution system as part of fecal matter from
humans or other animals. Biofilms may also harbor viral pathogens
(Quignon et al., 1997), but, unlike some bacterial pathogens, viruses
do not grow in the biofilm. However, a biofilm may protect the viruses
against disinfectants and help them survive longer.
Although not the basis for today's proposed rule, there are
additional waterborne pathogens that EPA is currently evaluating. These
include bacterial pathogens that may be free-living in the environment,
and thus not necessarily associated with fecal contamination. These
pathogens include Legionella (causes Legionnaires Disease and Pontiac
Fever), Pseudomonas aeruginosa, and Mycobacterium avium-intracellulare.
Many of these bacteria can colonize pipes of the distribution system
and plumbing systems and may play a role in causing waterborne disease
that is currently under study. EPA recognizes the potential risk of
such organisms, but believes that more research needs to be conducted
before they can be considered for regulation. Also, the Agency is aware
that Giardia and Cryptosporidium have occurred in ground water systems
(GWSs) (Hancock et al., 1998), causing outbreaks in such systems (Solo-
Gabriele and Neumeister, 1996). However, by definition under Sec. 141.2
ground waters with significant occurrence of large diameter pathogens
such as Giardia or Cryptosporidium are considered ground water under
the direct influence of surface water and are already subject to the
SWTR and IESWTR. The Agency is also not addressing in the GWR the
important issue of toxic or carcinogenic chemicals in the GWR. This
issue is instead covered in other regulations that address chemicals.
In order to assess the public health risk associated with drinking
ground water, EPA has evaluated information and conducted analysis in a
number of important areas discussed in more detail later. These
include: (1) Recent waterborne disease outbreak data; (2) dose-response
data and other health effects data from a range of pathogens; (3)
occurrence data from ground water studies and surveys; (4) an
assessment of the current baseline ground water protection provided by
existing regulations; and (5) an analysis of risk.
B. Waterborne Disease Outbreak Data
The purpose of this section is to present a detailed review of
waterborne disease outbreaks associated with ground waters. Outbreak
characterization is useful for indicating relative degrees of risk
associated with different types of source water and systems.
The Centers for Disease Control and Prevention (CDC) maintains a
database of information on waterborne disease outbreaks in the United
States. The database is based upon responses to a voluntary and
confidential survey form that is completed by State and local public
health officials. CDC defines a waterborne disease outbreak as
occurring when at least two persons experience a similar illness after
ingesting a specific drinking water (Kramer et al., 1996). Data from
the CDC database appears in Tables II-1, II-2, II-3, and II-4.
The National Research Council strongly suggests that the number of
identified and reported outbreaks in the CDC database (both for surface
and ground waters) represents a small percentage of actual waterborne
disease outbreaks (Safe Water From Every Tap, National Research
Council, 1997; Bennett et al., 1987; Hopkins et. al., 1985 for Colorado
data). In practice, most waterborne outbreaks in community water
systems are not recognized until a sizable proportion of the population
is ill (Perz et al., 1998; Craun 1996), perhaps 1% to 2% of the
population (Craun, 1996). Some of the reasons for the lack of
recognition and reporting of outbreaks, most of which were noted by the
National Research Council (1997), are as follows:
Some States do not have active disease surveillance
systems. Thus, States that report the most outbreaks may not be those
in which the most outbreaks occur.
Even in States with effective disease surveillance
systems, health officials may not recognize the occurrence of small
outbreaks. In cities, large outbreaks are more likely to be recognized
than sporadic cases or small outbreaks in which ill persons may consult
different physicians. Even so, health authorities did not recognize the
massive outbreak (403,000 illnesses) of waterborne cryptosporidiosis
that occurred in Milwaukee, WI, in 1993, until the disease incidence
was near or at its peak (MacKenzie et al., 1994). The outbreak was
recognized when a pharmacist noticed that the sale of over-the-counter
diarrheal medicine was very high and consequently notified health
authorities.
Most cases of waterborne disease are characterized by
general symptoms (diarrhea, vomiting, etc.) that cannot be
distinguished from other sources (e.g., food).
Only a small fraction of people who develop diarrheal
illness seek medical assistance.
Many public health care providers may not have sufficient
information to request the appropriate clinical test.
If a clinical test is ordered, the patient must comply, a
laboratory must be available and proficient, and a positive result must
be reported in a timely manner to the health agency.
Not all outbreaks are effectively investigated. Outbreaks
are included in the CDC database only if water quality and/or
epidemiological data are collected to document that drinking water was
the route of disease transmission. Monitoring after the recognition of
an outbreak may be too late in detecting intermittent or a one-time
contamination event.
Some States do not always report identified waterborne
disease outbreaks to the CDC. Reporting outbreaks is voluntary.
The vast majority of ground water systems are non-
community water systems (NCWSs). Outbreaks associated with NCWSs are
less likely to be recognized than those in community water systems
because NCWSs generally serve nonresidential areas and transient
populations.
There is also the issue of endemic waterborne disease. Endemic
waterborne disease may be defined as any waterborne disease not
associated with an outbreak. A more precise definition is the normal
level of waterborne disease in a community. Under this definition, an
outbreak would represent a spike in the incidence of disease. Based on
this definition, the level of endemic waterborne disease in a community
may be quite high. For example, 14%-40% of the normal gastrointestinal
illness in a community in Quebec was associated
[[Page 30205]]
with drinking treated water from a surface water source (Payment et
al., 1997). Significant levels of endemic disease could also be
associated with ground waters. Because endemic waterborne disease may
be a significant and substantially preventable source of health risk,
under the directive of the 1996 SDWA Amendments, EPA is jointly
pursuing with CDC a multi-city study of waterborne disease occurrence
in an effort to provide greater understanding of this risk. EPA
believes that some meaningful percentage of the nationwide occurrence
of endemic waterborne disease is in ground water systems (GWSs). EPA
believes that the prudent policy of prevention embodied in this
proposal with regard to identified sources of substantial microbial
risk to GWSs gains further justification as a counter to the endemic
occurrence of waterborne disease. EPA solicits comment and any data
that can increase knowledge of these endemic risks, in particular any
studies on such risk in GWSs.
CDC Waterborne Disease Outbreak Data
Outbreak data collected by CDC are presented in Tables II-1, II-2 ,
II-3, and II-4. Table II-1 provides outbreak data for all public water
systems (surface and ground water). Table II-2 shows sources of
waterborne disease outbreaks for GWSs. Table II-3 identifies the
etiology of waterborne outbreaks in GWSs. Table II-4 shows causes
associated with waterborne disease outbreaks and illnesses in GWSs.
According to CDC, between 1971 and 1996 a total of 643 outbreaks
and 571,161 cases of illnesses were reported (see Table II-1); however,
the total includes 403,000 cases from a single surface water outbreak
caused by Cryptosporidium in Milwaukee, WI in 1993. Excluding the
Milwaukee outbreak from the data set, 642 outbreaks and 168,161 cases
of illness were reported during the same period of time. Ground water
sources were associated with 371 (58%) of the total outbreaks and 16%
of the associated illness (54% of the illness if the Milwaukee outbreak
is excluded). In comparison, surface water sources were associated with
216 (33%) of the total outbreaks and 82% of the associated illness (40%
of the illness if the Milwaukee outbreak is excluded). Although the
data in Table II-1 indicate that NCWSs using ground water had twice as
many outbreaks as CWSs using ground water, this may reflect the fact
that there are over twice as many NCWSs as CWSs.
The outbreak data indicate that the major deficiency in ground
water systems was source water contamination--either untreated or
inadequately treated ground water (see Table II-2). Contaminated source
water was the cause of 86% of the outbreaks in ground water systems.
Contamination due to source water was the cause of 68% of the outbreaks
for CWSs, while for NCWSs it was 92%. Distribution system deficiencies
were associated with 29% of the outbreaks in CWSs and in five percent
of the NCWSs.
Of the 371 outbreaks in ground water systems, 91 (25%) were
associated with specific viral or bacterial pathogens, while 22 (6%)
were associated with chemicals (see Table II-3). Etiologic agents were
not identified in 232 (63%) outbreaks. The diversity of disease agents
is similar to that of surface water, with a variety of protozoa,
viruses, and bacteria. As stated previously, a ground water with
Cryptosporidium or Giardia is, by definition, a ``ground water under
the direct influence of surface water'', and is thus subject to the
microbial treatment requirements of a surface water system (i.e., SWTR
or IESWTR). According to CDC's data, bacterial pathogens were
responsible for more outbreaks (57) than were viral pathogens (34).
However, EPA suspects that many, perhaps a majority, of the outbreaks
where an agent was not determined (232) were virus-caused, given the
fact that it is generally more difficult to analyze for viral pathogens
than bacterial pathogens. The fecal bacterial pathogen, Shigella,
caused far more reported outbreaks (eight percent) than any other
single agent.
Table II-4 shows outbreak data since 1991, the year in which the
TCR became effective. Untreated ground water and inadequate treatment
were collectively associated with 73% of the outbreaks in ground water
systems between 1991-1996.
Large outbreaks are rarely associated with ground water systems
because most ground water systems are small. However, one large
outbreak occurred in Georgetown, TX, in 1980 (Hejkal et al., 1982)
where 7,900 people became ill. Coxsackievirus and hepatitis A virus
were found in the raw well water in a karst hydrogeologic setting; the
outbreak was the result of source water contamination. Another occurred
in 1965, in Riverside, CA, where about 16,000 illnesses resulted from
exposure to Salmonella typhimurium in the source water (Boring, 1971).
Most of the outbreaks were caused by agents of gastrointestinal
illness. Normally, the disease is self-limiting and the patient is well
within one week or less. However, in some cases, deaths have occurred.
In 1989, four deaths (243 illnesses) occurred in Cabool, MO, as a
result of distribution system contamination by E. coli 0157:H7
(Swerdlow et al., 1992; Geldreich et al., 1992). In 1993, seven deaths
(650 illnesses) occurred in Gideon, MO, as a result of distribution
system contamination by Salmonella typhimurium (Angulo, 1997). Both
cases involved ground water systems. Waterborne disease in ground water
systems has also caused serious illness such as hemolytic uremic
syndrome (six reported cases in two outbreaks), which includes kidney
failure, especially in children and the elderly. Two cases of hemolytic
uremic syndrome were reported during the Cabool outbreak, the affected
individuals being three and 79 years of age. Deep wells are not immune
from contamination; for example, an outbreak of gastroenteritis caused
by the Norwalk virus (900 illnesses) was associated with a 600-foot
well (Lawson et al., 1991).
Collectively, the data indicate that outbreaks in ground water
systems are a problem and that source contamination and inadequate
treatment (or treatment failures) are responsible for the great
majority of outbreaks. The outbreaks are caused by a variety of
pathogens, most of which cause short term gastrointestinal disease.
Table II-1.--Comparison of Outbreaks and Outbreak-Related Illnesses From Ground Water and Surface Water for the Period 1971-1996 \1\ \2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Outbreaks in Outbreaks in
Water source Total outbreaks\1\ Cases of illnesses CWSs NCWSs Total CWS\4\ Total NCWS\4\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Ground........................... 371 (58%) 90,815 (16%) 113 258 43,908 112,940
Surface.......................... 216 (33%) 469,721\2\ (82%) 142 43 10,760 2,848
Other............................ 56 (9%) 10,625 (2%) 29 19 .............. ..............
[[Page 30206]]
All Systems\3\................... 643 (100%) 571,161 (100%) 284 320 54,668 115,788
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Modified from Craun and Calderon, 1994, plus 1995-1996 data.
\2\ Includes 403,000 cases of illness from a single outbreak in Milwaukee, Wisconsin, 1993.
\3\ Includes outbreaks in CWSs + NCWSs + Private wells.
\4\ Safe Drinking Water Information System, 1998.
Table II-2.--Sources of Waterborne Disease Outbreaks, Public Ground Water Systems, 1971-1996 1,2.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Percent of Percent of Percent of
Type of contamination Total total CWSs total NCWSs total
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source.............................................. 274 86 53 68 221 92
Untreated........................................... 150 47 20 26 130 54
Disinfected......................................... 122 38 31 40 91 38
Filtered............................................ 2 1 2 3 0 0
Distribution System..................................... 35 11 23 29 12 5
Unknown Cause........................................... 9 3 2 3 7 3
-----------------------------------------------------------------------------------------------
Total............................................... 318 100 78 100 240 100
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Source water could not be identified for 29 CWSs and 19 NCWSs with outbreaks, and thus these systems are not included in the table.
\2\ Excludes outbreaks caused by protozoa and chemicals.
Table II-3.--Etiology of Outbreaks in Ground Water Systems, 1971-96,
CWSs and NCWSs
------------------------------------------------------------------------
Causative agent Outbreaks Percent
------------------------------------------------------------------------
Undetermined................................ 232 63
Chemical.................................... 22 6
Giardia..................................... \1\ 21 6
Cryptosporidium............................. \1\ 4 1
E. histolytica.............................. 1 1
Total Protozoa.............................. 26 7
Hepatitis A................................. 18 5
Norwalk Agent............................... 16 5
Total Virus................................. 34 9
Shigella.................................... 30 8
Campylobacter............................... 10 3
Salmonella, non-typhoid..................... 10 3
E. coli..................................... 4 1
S. typhi.................................... 1 1
Yersinia.................................... 1 1
Plesiomonas shigelloides.................... 1 1
---------------------------
Total Bacteria.............................. 57 15
===========================
Total....................................... 371 100
------------------------------------------------------------------------
\1\ Ground waters with Giardia and Cryptosporidium are regulated under
the SWTR and IESWTR. These systems would likely not be considered
ground water systems for purposes of this rule.
Table II-4.--Causes of Outbreaks in Ground Water Systems, 1991-1996
----------------------------------------------------------------------------------------------------------------
Percent of
Number of Cases of outbreak-
Cause outbreaks illness related
illnesses
----------------------------------------------------------------------------------------------------------------
Untreated Ground Water.......................................... 18 2924 51
Distribution System Deficiency.................................. 6 944 17
Treatment Deficiency............................................ 17 1260 22
Miscellaneous, Unknown Cause.................................... 3 568 10
-----------------------------------------------
Total....................................................... 44 5696 100
----------------------------------------------------------------------------------------------------------------
\1\ Excludes protozoa and chemicals.
[[Page 30207]]
C. Ground Water Occurrence Studies
The purpose of this section is to present data on the occurrence of
waterborne pathogens and indicators of fecal contamination in ground
water supplying PWS wells. These data are important to GWR development
because they provide insight on: (1) The extent to which ground water
may be contaminated; (2) possible fecal indicators for source water
monitoring under the GWR; and (3) a national estimate of ground water
pathogen occurrence. In addition, determining the occurrence of
microbial contaminants in ground water sources of drinking water is
necessary to yield a quantified national estimate of public health
risk.
EPA has reviewed data from13 recent or on-going studies of pathogen
and/or fecal indicator occurrence in ground waters that supply PWSs.
While most of these studies were not designed to yield a nationally
representative sample of ground water systems, one of the studies
(Abbaszadegan et al., 1999, or the ``AWWARF study'') was later expanded
to include a nationally representative range of hydrogeologic settings.
This study was used as the basis of EPA's quantitative assessment of
baseline risk from viral contamination of ground water, which is also a
component of the quantitative benefits assessment for the proposed
rule. Short narratives on each of the studies are provided in the next
sections. The study design and results for each study are summarized in
Table II-6, at the end of the narratives. The Agency decided not to
combine the data from these studies, because of the different method
protocols and scopes.
Each occurrence study investigated a combination of different
pathogenic and/or indicator viruses and bacteria. Indicator viruses and
bacteria may be non-pathogenic but are associated with fecal
contamination and are transmitted through the same pathways as
pathogenic viruses and bacteria. The samples analyzed in each study
were tested for viral pathogens such as enteroviruses (a group of human
viruses also referred to as ``total cultureable viruses'') and/or
bacterial pathogens such as Legionella and Aeromonas. Several studies
used the polymerase chain reaction (PCR) as part of the method for
determining the presence of pathogenic viruses. Bacterial indicators of
fecal contamination tested included enterococci (or fecal streptococci,
which are closely related), and fecal coliforms (or E. coli, which is
closely related), and Clostridium perfringens. Most studies tested for
total coliforms, which are not considered a direct fecal indicator
since they also include coliforms that live in soil. Viral indicators
of fecal contamination were all bacteriophage, which are viruses that
infect bacteria. Among the bacteriophage tested were somatic coliphage
and/or male-specific coliphage, both of which infect the bacterium E.
coli. Bacteroides phage were tested in two studies and Salmonella phage
in one study.
While this section presents a summary of each study, a more
detailed explanation of one study (Abbaszadegan et al., 1999) (AWWARF
Study) is provided, as it is the broadest study in scope. The
hydrogeology of individual wells is mentioned in addition to the
microbial results, because EPA considers hydrogeology an important
factor in source water contamination. Hydrogeology is discussed in
greater detail in section III.B.
1. Abbaszadegan et al. (1999) (AWWARF Study)
Of the 13 studies, the AWWARF study sampled the largest number of
wells, examined the widest array of well and system characteristics,
and tested sites in 35 States across the U.S., located in hydrogeologic
settings representative of national hydrogeology. The objectives of the
AWWARF study were to: (1) Determine the occurrence of virus
contamination in source water of public ground water systems; (2)
investigate water quality parameters and occurrence of microbial
indicators in ground water and possible correlation with human viruses;
and (3) develop a statistically-based screening method to identify
wells at risk of fecal contamination. A summary of AWWARF results are
presented in Tables II-5 and II-6.
Many of the initial sites were selected to evaluate the
effectiveness of a method based on the reverse-transcriptase,
polymerase chain reaction (RT-PCR) technique to detect pathogenic
viruses in ground water. Sites for this portion of the study were
selected based on the following criteria: (1) Ground water sites with
high concentrations of minerals, metals, or TOC; (2) sites with a
previous detection of any virus or bacteria in the ground water source;
(3) sites with potential exposure to contaminants due to agricultural
activities near the well, industrial activities near the well, or
septic tanks near the well; and (4) sites with different pH values,
temperatures, depths, production capacities and aquifer types. Sites
were selected for the virus occurrence project based upon their
geological characteristics to balance out the range of geologies so
that the sites in aggregate more closely matched the national geologic
profile of ground water sources. Sites for the virus occurrence study
were selected from an initial mailing to 500 utilities that currently
disinfect their water; 160 utilities with 750 wells volunteered to be
included in the study. In total, 448 wells were sampled for the study.
AWWARF excluded sites from the investigation if: (1) It was known to be
under the influence of surface water; (2) the well log records were not
available; or (3) it was considered poorly constructed.
EPA subsequently compared nitrate concentrations from a national
database of nitrate concentrations in ground water (Lanfear, 1992) with
nitrate data measured in the AWWARF study wells. The purpose of the
comparison was to determine if there was any statistically significant
difference between the nitrate levels in the AWWARF wells as compared
with the national distribution of nitrate concentration data. Nitrate
was chosen for this comparison because there is a large, national
database available. Each data set contained 216 samples selected so
that proportionately, wells of equal depth were analyzed in each
comparison. The national data were selected randomly from a database of
more than 100,000 wells; all available AWWARF data were used. In
analyzing the data, EPA noted that the national data is biased by
multiple sampling of many shallow monitoring wells in farming regions
leading to a few wells having exceptionally high nitrate levels. In
order to minimize the impact of these wells on the analysis, EPA chose
a small random subset comparable in size to the sample in the AWWARF
study. Thus, the data are not directly comparable with PWS wells.
Census data were used to divide the national nitrate database into
urban and rural components. The analysis showed that the AWWARF wells
had nitrate concentrations that were not significantly different from
the national data or from the urban and rural components. Thus, using
nitrate concentration as a surrogate, EPA concludes that, by this
measure, the AWWARF wells are nationally representative.
All samples were collected by the systems. AWWARF provided a sample
kit containing all needed equipment and a video illustrating the
details of appropriate sampling and storage procedures. A total of 539
samples were collected from 448 sites in 35 States. The preliminary
results indicate that of the 448 wells sampled, about 64% were located
in unconsolidated aquifers, 27% in consolidated aquifers including
consolidated sedimentary strata, and 9% in unknown geology.
Unconsolidated aquifers are made of
[[Page 30208]]
loosely packed (uncemented) particles, such as sand grains or gravel,
while consolidated aquifers are comprised of compacted (cemented)
particles or crystalline rock (e.g., granite, limestone). As discussed
further in section III.B., the degree and type of consolidation may
affect the transport of pathogens from a source of fecal contamination
to the well. The percentages of sites sampled from these geologic
settings are similar to those of national ground water production from
unconsolidated and consolidated hydrogeologic settings (modified by
AWWARF, from United States Geological Survey (USGS) Circular 1081,
1990). The data indicate that 174 sites (39%) were within 150 feet of a
known sewage source, and an additional 127 sites (28%) were within 550
feet of a known sewage source. There is no comparable data on the
distribution nationally of wells relative to sewage sources. EPA notes
however, that the proximity to these sources is not inconsistent with
State standards across the country. For example, 41 States have setback
distances (the minimum distance between a source of contamination and a
well) that are less than or equal to 100 feet for sources of microbial
contaminants. Only five States appear to require setback from all
sewage sources of more than 200 feet. The preliminary results also
indicated that a total of 25 sites were sampled more than once. Most
sites were from systems that serve greater than 3,300 people, and
almost all systems maintain a disinfectant residual.
In the study, systems collected at least 400 gallons (1,512 liters)
of water and concentrated it using a filter-adsorption and elution
method. The concentrated samples were then sent to the researchers for
analysis. The presence of enteroviruses was determined by two
procedures: a cell culture assay and a procedure using the RT-PCR
technique. The RT-PCR technique was also used to determine the presence
of hepatitis A virus, rotavirus, and Norwalk virus. The researchers
also tested each well for total coliforms, enterococci, Clostridium
perfringens, somatic coliphage, and male-specific coliphage to
establish their relationship with enterovirus and to get a better
indication of the percentage of fecally contaminated wells.
Preliminary results indicated that fecal contamination occurs in a
subset of PWS wells (see Table II-5). The investigators detected
pathogenic viruses, either by cell culture or RT-PCR analyses, in a
significant percentage of samples.
Table II-5.--Preliminary Results of AWWARF Study
------------------------------------------------------------------------
Percent of wells positive
Assay (number positive/samples
analyzed)
------------------------------------------------------------------------
Enteroviruses (cell culture)............ 4.8% (21/442)
Bacterial Indicators.................... 15.1%
Total coliforms..................... 9.9% (44/445)
enterococci......................... 8.7% (31/355)
Clostridium perfringen spores....... 1.8% (1/57)
Coliphage Indicators.................... 20.7%
Male-specific coliphage (Salmonella 9.5% (42/440)
WG-49 host).
Somatic coliphage (E. coli C host).. 4.1% (18/444)
Somatic and male-specific coliphage 10.8% (48/444)
(E. coli C-3000 host).
PCR..................................... 31.5%
Norwalk viruses (PCR)............... 0.96% (3/312)
Enteroviruses (PCR)................. 15.9% (68/427)
Rotaviruses (PCR)................... 14.6% (62/425)
Hepatitis A viruses (PCR)........... 7.2% (31/429)
------------------------------------------------------------------------
2. Lieberman et al., (1994, 1999) (EPA/AWWARF Study)
The study objectives included the following: (1) develop and
evaluate a molecular biology (PCR) monitoring method; (2) obtain
occurrence data for human enteric viruses and Legionella (a bacterial
pathogen) in ground water; and (3) assess the microbial indicators of
fecal contamination. These objectives were accomplished by sampling
vulnerable wells nominated by States to confirm the presence of fecal
indicators (Phase I) and then choosing a subset of these for monthly
sampling for one year (Phase II).
In Phase I, well vulnerability was established using historical
microbial occurrence data and waterborne disease outbreak history,
known sources of human fecal contamination in close proximity to the
well, and sensitive hydrogeologic features (e.g., karst). Ninety-six of
the 180 potentially vulnerable wells were selected for additional
consideration. Selected wells were located in 22 States and 2 US
territories. Additional water quality information was then successfully
obtained for 94 of the wells through use of a single one liter grab
sample which was subsequently tested for several microbial indicators
(see Table II-6). The wells from Phase I served as the well selection
pool for Phase II sampling.
In Phase II, 23 of the Phase I wells were selected for monthly
sampling for one year. Seven additional wells were selected from a list
of state-nominated wells for a total of 30 wells, located in 17 States
and 2 US territories. The additional seven wells were based on other
criteria, including historical water quality data, known contaminant
sources in proximity to the well, hydrogeologic character or to replace
wells that were no longer available for sampling. Samples were analyzed
for enteroviruses, Legionella, enterococci, E. coli, Clostridium
perfringens, total coliforms, somatic coliphage, male-specific
coliphage and Bacteroides phage. For each sample analyzed for enteric
viruses and bacteriophages, an average of approximately 6,000 liters of
water were filtered and analyzed by cell culture.
Twenty samples from seven wells were enterovirus positive and were
speciated by serotyping. Coxsackievirus and echovirus, as well as
reovirus, were identified. The range in virus concentration in
enterovirus-positive samples was 0.9-212 MPN/100 liters (MPN, or most
probable number, is an estimate of concentration).
The hydrogeologic settings for the seven enterovirus-positive wells
were
[[Page 30209]]
karst (3), a gravel aquifer (1), fractured bedrock (2), and a sandy
soil and alluvial aquifer (1). The karst wells were all positive more
than once. The gravel aquifer was also enterovirus-positive more than
once, with 4 of 12 monthly samples positive.
3. Missouri Ozark Aquifer Study #1
The purpose of this study was to determine the water quality in
recently constructed community public water system wells in the Ozark
Plateau region of Missouri. This largely rural region is characterized
by carbonate aquifers, both confined and unconfined, with numerous
karst features throughout. A confining layer is defined in this study
as a layer of material that is not very permeable to ground water flow
and that overlays an aquifer and acts to prevent water movement into
the aquifer.
The US Geological Survey, working with the Missouri Department of
Natural Resources, selected a total of 109 wells, in both unconfined
and confined aquifers (Davis and Witt, 1998, 1999). In order to
eliminate poorly constructed wells from the study, most of the selected
wells had been constructed within the last 15 years. Wells were also
selected to obtain good coverage of the aquifer and to reflect the
variability in land use. All wells were sampled twice, in summer and
winter. Evidence of fecal contamination was found in a number of wells.
Thirteen wells had samples that were PCR-positive for enterovirus.
4. Missouri Ozark Aquifer Study #2
The purpose of this study is to determine the water quality in
older (pre-1970) CWS wells in the Ozark Plateau region of Missouri to
supplement the Missouri Ozark Aquifer Study #1, by Davis and Witt
(1998, 1999). This largely rural region is characterized by carbonate
aquifers, both confined and unconfined, with numerous karst features
throughout.
The US Geological Survey, working with the Missouri Department of
Natural Resources, sampled a total of 106 wells (Femmer, 1999), in both
unconfined and confined aquifers. Wells (all of which were constructed
before 1970) were selected for monitoring to obtain good coverage of
the aquifer, and to reflect the variability in land use. Priority was
given to wells that had completion records, well operation and
maintenance history and wells currently being used. Each well was
sampled once (during the spring). No wells were enterovirus-positive by
cell culture.
5. Missouri Alluvial Aquifer Study
The purpose of this study was to determine water quality in wells
located in areas that were subjected to recent flooding. The wells are
located primarily in the thick, wide alluvium of the Missouri and
Mississippi rivers. Sampling (117 samples) occurred during the period
of March through June 1996. Twelve wells served as control wells
(uncontaminated) and were sited in ``deep rock'' aquifers or upland
areas. A total of 64 wells were sampled.
Many of the wells had been flooded. Fifty-five were affected by a
flood in 1995. In addition, some of the wells sampled had been flooded
around the surface well casing prior to the sampling event, and several
were flooded at the time of sampling (Vaughn, 1996).
6. Wisconsin Migrant Worker Camp Study
The purpose of this study was to determine the quality of drinking
water in the 21 public ground water systems serving migrant worker
camps in Wisconsin (US EPA, 1998a). These transient, non-community
water systems are located in three geographic locations across the
State. Each well was sampled monthly for six months, from May through
November, 1997. The study conducted sampling for male-specific
coliphage, total coliforms and E. coli. When detections of coliforms
occurred, the specific type of coliform was further identified
(speciated). One total coliform positive sample was identified to
contain Klebsiella pneumoniae. Along with the microbial indicators,
nitrate and pesticides were also measured.
Other factors were compared to the microbial and chemical sampling
results of the study. Well construction records were available for 14
of the wells. The mean casing depth was 109 feet (range 40 to 282 feet)
and the mean total well depth was 155 feet (range 44 to 414 feet). Most
of these 14 wells are also reported to terminate in a sand or sandstone
formation.
Investigators detected male-specific coliphage in 20 of 21 wells
during the six-month sampling period, but never detected E. coli. In
addition, four wells had nitrate levels that exceeded the EPA MCL for
nitrate.
7. EPA Vulnerability Study
The purpose of this study was to conduct a pilot test of a new
vulnerability assessment method by determining whether it could predict
microbial monitoring results (U.S. EPA 1998b). The vulnerability
assessment assigned low or high vulnerability to wells according to
their hydrogeologic settings, well construction and age, and distances
from contaminant sources. A total of 30 wells in eight States were
selected to represent ten hydrogeologic settings. Selection was based
on the following criteria: (1) Wells representing a variety of
conditions relevant to the vulnerability predictions; (2) wells with
nearby sources of potential fecal contamination; and (3) wells with
sufficient well and hydrogeologic information available.
Samples were taken and tested for enteroviruses (both by cell
culture and PCR), hepatitis A virus (HAV) (by PCR), rotavirus (by PCR),
Norwalk virus (by PCR), and several indicators (total coliforms,
enterococci, male-specific coliphage, and somatic coliphage). The only
positive result was one PCR sample positive for HAV.
8. US-Mexico Border Study
The purpose of this study was to determine water quality in wells
sited in alluvium along the Rio Grande River between El Paso, Texas and
the New Mexico border (U.S. EPA, in preparation). The 17 wells selected
were perceived to be the most vulnerable, based on well depth, chloride
concentration and proximity to contamination sources, especially the
Rio Grande River.
The wells tested are relatively shallow and all serve less than
10,000 people. One well serves 8,000 people, while seven wells serve
fewer than 100 people. Well depths range from 65 feet to 261 feet, but
most are about 150 feet deep. This signifies that water was collected
from the middle aquifer, a shallow but potable aquifer. Wells shallower
than 65 feet contain chloride concentrations prohibitively high for
drinking water.
Samples were collected from each well and tested for enteroviruses
(by cell culture), somatic coliphage, and male-specific coliphage. None
of the sites were positive for any of the viruses tested.
9. Whittier, CA, Coliphage Study
The purpose of this study was to determine the presence of fecal
contamination in all wells located within 500 feet down-gradient of a
water recharge infiltration basin (Yanko et al., 1999). The 23 wells
were sampled once per month for six months.
The wells are sited in similar hydrogeologic settings, although
they vary in age and depth. The hydrogeologic setting is primarily a
thick layer of unconsolidated sand, with lesser amounts of other sized
grains. About 30% of the recharge volume to
[[Page 30210]]
the wells is reclaimed water. Wells were all constructed between 1919
and 1989 and produce water from depths ranging from 60-888 feet.
The wells were sampled monthly for a six month period. The samples
were tested for total coliforms and indicators of fecal contamination,
including male specific coliphage, somatic coliphage, and E. coli.
Coliphage were found in all wells, and repeatedly in 20 of the 23
wells.
10. Oahu, HI Study
The purpose of this study was to establish a water quality
monitoring program to assess the microbial quality of deep ground water
used to supply Honolulu (Fujioka and Yoneyama, 1997). A total of 71
wells were sampled, 32 of which were sampled for viruses and 39 of
which were sampled for bacteria. The wells are located in carbonate or
basalt aquifers.
Each of the wells was tested for several pathogens and indicators
of fecal contamination. Bacterial samples taken from 39 wells (79
samples) were tested for total coliforms, fecal streptococci,
Clostridium perfringens, heterotrophic bacteria (by m-HPC), and
Legionella (by PCR). Sample volumes were 100 mL for C. perfringens and
heterotrophic bacteria, and both 100 mL and 500 mL for coliforms and
fecal streptococci. For FRNA coliphage (male-specific coliphage), one
liter samples from 32 wells (35 samples) were tested by membrane
adsorption-elution method, while 24 wells (24 samples) were tested by
an enrichment technique developed by Yanko. None of the wells were
coliphage-positive, and only one sample each was positive for E. coli
and fecal streptococci.
11. New England Study
The purpose of this study was to: (1) Determine the prevalence of
enteric pathogens in New England's public water supply wells; (2)
assess the vulnerability of different systems; and (3) evaluate various
fecal indicators.
Wells were selected based on the following criteria: (1) Must have
constant withdrawal throughout the year; (2) must be near septic
systems, (3) should have, if possible, a history of violations of the
MCL for total coliforms or elevated nitrate levels; and (4) must not
have direct infiltration by surface water (Doherty, 1998).
Wells were nominated, characterized, selected and sampled by
regulatory staff of Connecticut, Maine, Massachusetts, New Hampshire,
Rhode Island, and Vermont. The selection process considered wells in
different hydrogeologic settings. Of the 124 total wells, 69 (56%) were
located in unconfined aquifers, 31 (25%) were located in bedrock
aquifers, 10 (8%) were located in confined aquifer hydrogeologic
settings, and 14 (11%) were located in unknown aquifer settings. Each
well was sampled quarterly for one year. Enterococci were identified in
20 of 124 wells (16%) and in 6 of 31 (19%) bedrock aquifer wells. Two
wells were enterovirus-positive using cell culture methods, both in
unconsolidated aquifers. One of these two wells is 38 feet deep and the
other well is 60 feet deep. Final results from this study are not yet
available.
12. California Study
The purpose of this research is two-fold: (1) To assess the
vulnerability of ground water to viral contamination through repeated
monitoring, and (2) to assess the potential for bacteria and coliphages
to serve as indicators of the vulnerability of ground water to viral
contamination (Yates 1999).
Eighteen wells were tested monthly for human enteroviruses (by cell
culture (direct RT-PCR, Immunomagnetic separation reverse transcriptase
(IMS-RT-PCR) and integrated cell culture RT-PCR) and PCR), HAV (by
PCR), rotaviruses (by PCR), somatic and male-specific coliphage, and
total coliforms and fecal streptococci. The depth of the wells is
variable, but is on the order of about 200 feet (the deeper the well,
the less likely contamination). There are some intermittent confining
layers.
Of the 230 samples tested for enteroviruses, 6 samples from 6 of
the 18 wells were cell culture positive for enteroviruses. Final
results from this study are not yet available.
13. Three State PWS Study (Wisconsin, Maryland and Minnesota)
The purpose of the three-state study is to characterize the extent
of viral contamination in PWS wells by testing wells in differing
hydrogeologic regions and considering contamination over time
(Battigelli, 1999). Wells were sampled quarterly for one year in
Wisconsin (25 wells), Minnesota (25 wells), and will be sampled in
Maryland (up to 35 wells).
Three wells in Wisconsin were positive for enteroviruses by cell
culture. Final results for this study are not yet available.
Table II-6.--Ground Water Microbial Occurrence Studies/Surveys
----------------------------------------------------------------------------------------------------------------
Pathogenic viruses,
Indicators monitored Legionella (number
Number of PWS Sampling frequency/ (number of POS. of POS. wells/number
Study wells sampled volume wells/number of of wells total,
and location wells total, unless unless otherwise
otherwise indicated) indicated)
----------------------------------------------------------------------------------------------------------------
1. AWWARF Study.............. 448 wells; 35 Sampled once (25 Male-sp. coliphage, Cell Culture:
States. wells sampled host Salmonella WG- Enterovirus (21/
twice); 539 samples 49 (42/440); 442); PCR:
total, not all Somatic coliphage, Rotavirus (62/425),
analyses conducted host E. coli C (18/ Hepatitis A virus
on all samples. 444); Coliphage, (31/429), Norwalk
Sampling volumes: host E. coli C-3000 virus (3/312),
1512L eluated for (48/444); Total Enterovirus (68/
virus analyses (5 coliform (44/445); 427).
liter equivalent enterococci (31/
for RT-PCR, 600L 355); C.
for cell culture), perfringens (1/57).
Coliphage 15L,
Bacteria 200 mL.
2a. EPA/AWWARF Phase I Study. 94 wells; 22 One sample, 1 L..... Somatic coliphage 5/ ....................
States plus PR 94; 1*; Total
and USVI. coliform 31/94; 9*;
E. coli 18/94; 5*;
enterococci 17/94;
3*; C. perfringens
4/94; 0*;
*indicates number
of wells positive
in Phase I which
were not positive
or not sampled in
Phase II.
[[Page 30211]]
2b. EPA/AWWARF--Phase II 30, of which 23 Monthly for one Somatic coliphage Cell Culture:
Study. were from year; Average (16/30); Male Enterovirus (7/30);
Phase I; 17 volume filtered: specific coliphage PCR: polio, entero,
States plus PR 6,037 L; (6/30); Bacteroides Hepatitis A,
and USVI. Microscopic bacteriophage (6/ Norwalk, rota
Particulate 30); Somatic (results not
Analysis (MPA) data Salmonella available), (300+
available for each bacteriophage (6/ samples from 30
well. 30); Total coliform wells; several
(24/30); wells cell culture
enterococci (21/ positive multiple
30); C. times); Legionella
perfringens(10/30); sp. (14/30),
E. coli (15/30); E. Legionella
coli H7:O157 (0/7). pneumophila (6/30).
3. Missouri Ozark Plateau 109 wells...... Two samples/well, 25 Somatic coliphage (1/ Cell Culture:
Study #1 (Davis and Witt, wells sampled once 109); Male specific Enterovirus (0/
1999). for tritium, 200- coliphage (10/109); 109); PCR:
300 L ground water Fecal streptococci Enterovirus (13/
filtered at the (1/109); Fecal 109).
well head. coliform (2/109);
E. coli (0/109).
4. Missouri Ozark Plateau 106 wells...... One sample, 200-300 Somatic coliphage (3/ Study in progress;
Studies #2 (Femmer, 1999) L filtered at the 106); Male specific Cell Culture:
(pre-1970 wells). well head. coliphage (3/106); Enterovirus (0/
Fecal streptococci 106).
(8/106); Fecal
coliform (8/106);
E. coli (9/106).
5. Missouri Alluvial Study... 64 wells....... Sampling occurred Somatic coliphage (1/ Cell Culture:
during a four month 81); Male specific Enterovirus (1//
period. Some coliphage (1/81); 81).
sampling done Bacteroides
during flooding. bacteriophage (1/
81); Total coliform
(33/81); Fecal
coliform (5/81);
Fecal streptococci
(12/81).
6. Wisconsin Migrant Worker 21 wells....... Monthly: Bacteria--6 Male specific ....................
Camp Study. mos.; Phage--5 coliphage (20/21);
mos.; Bacteria--100 Total coliform (14/
mL; Phage--1L. 21); E. coli (0/
21); K. pneumoniae
(1/21).
7. EPA Vulnerability Study... 30 wells in 8 Each well visited Male specific Cell Culture:
States. once. Two 1L grab coliphage (0/30); enterovirus (0/30);
samples and 1500-L Somatic coliphage PCR: HAV (1/30),
sample Equiv. vol. (2/24; large Rota (0/30),
650L for volume); Total Norwalk (0/30),
enterovirus, 100 mL coliform (4/30); enterovirus (0/30).
for bacteria, 10 mL enterococci (0/30).
to 100L for
coliphage, PCR?.
8. US-Mexico Border Study (TX 17 wells....... 3 (300-1000 gallon) Male specific Cell Culture:
and NM). samples/well. coliphage (0/17); Enterovirus (0/17).
Somatic coliphage
(0/17).
9. Whittier, CA, Coliphage 23 wells....... Once a month for 6 Male specific ....................
Study. months; 4L samples. coliphage (18/23);
Somatic coliphage
(23/23); Total
coliform (4/23); E.
coli (0/23).
10. Oahu, Hawaii Study....... Virus--32 wells Each well sampled 1- Male specific Legionella sp. (PCR;
Bacteria--39 4 times; total 79 coliphage (0/32); 15/26), Legionella
wells. samples, Virus--1- Somatic coliphage pneumophila (PCR; 1/
L; C. perfringens, (0/32); Total 27).
HPC--0.1L; Coliform (3/39); E.
Coliforms, fecal coli (1/39); Fecal
strep--0.1L and Streptococci (1/
0.5L. 39); C. perfringens
(0/39).
11. New England Study........ 124 wells; 6 Each well sampled Study in progress; Study in progress;
States. four times over one Male specific Cell Culture:
year; Up to 1500-L coliphage (4/79); Enterovirus (2/
sample for virus. Somatic coliphage 122); PCR:
(1/70); Total Enterovirus
coliform (27/124); (results not
Aeromonas available).
hydrophila (19/
122); C.
perfringens (6/
119); E. coli (0/
124); enterococci
(20/124).
12. California Study......... 18 wells....... 14 of 18 wells Study in progress; Study in progress;
sampled 12 to 22 Male specific Cell Culture:
times (monthly); coliphage: (hosts enterovirus (6/18);
Average sample E. coli FAMP, S. PCR: HAV (0/18),
volume 1784 L typhimurium WG-49) Rota (0/18),
(range 240-3331 L) (4/18); Somatic enterovirus (direct
1 l grab sample for coliphage: host E. RT-PCR) (6/18), IMS-
indicators; coli 13706 (13/18); RT-PCR (10/18),
(Coliphage analyzed Total coliform (7/ Integrated Cell
using 10 mL grab 18); Fecal Culture PCR
samples, 1-L streptococci (0/18). enterovirus (4/
enrichment samples, 18)).
IMDS filter eluates
and filter
concentrates).
13. Three-State Study 50 wells (25 Each well sampled Study in progress; Study in progress;
(Wisconsin, Maryland, from MN, 25 four times over one Somatic coliphage; Cell Culture:
Minnesota). from WI, year. Male specific enterovirus (3/25).
additional coliphage; Total
wells from MD). coliform;
enterococci; C.
perfringens; E.
coli.
----------------------------------------------------------------------------------------------------------------
[[Page 30212]]
D. Health Effects of Waterborne Viral and Bacterial Pathogens
To assess the public health risk associated with a waterborne
pathogen, or group of pathogens, both occurrence data and health
effects data are needed. The previous section discussed the occurrence
in ground water of pathogens and indicators of fecal contamination.
This section discusses the health effects associated with waterborne
pathogens, first viral agents and then bacterial.
Viral Pathogens
Table II-7 and II-8 list viral and bacterial pathogens that have
caused waterborne disease in ground waters. Unlike some bacterial
pathogens, viruses cannot reproduce or proliferate outside a host cell.
Viruses that infect cells lining the human gut are enteric viruses.
With a few exceptions, viruses that can infect human cells typically
cannot infect the cells of other animals and vice versa. This contrasts
with many bacterial pathogens, which often have a broader host range.
Some enteric viral pathogens associated with water may infect cells in
addition to those in the gut, thereby causing mild or serious secondary
effects such as myocarditis, conjunctivitis, meningitis or hepatitis.
There is also increasing evidence that the human body reacts to foreign
invasion by viruses in ways that may also be detrimental. For example,
one hypothesis for the cause of adult onset diabetes is that the human
body, responding to coxsackie B5 virus infection, attacks pancreatic
cells in an auto-immune reaction as a result of similarities between
certain pancreas cells and the viruses (Solimena and De Camilli, 1995).
When humans are infected by a virus that infects gut cells, the
virus becomes capable of reproducing. As a result, humans shed viruses
in stool, typically for only a short period (weeks to a few months).
Shedding often occurs in the absence of any signs of clinical illness.
Regardless of whether the virus causes clinical illness, the viruses
being shed may infect other people directly (by person-to-person
spread, contact with infected surfaces, etc.) and is referred to as
secondary spread. Waterborne viral pathogens thus may infect others via
a variety of routes.
Table II-7.--Some Illnesses Caused by Fecal Viral Pathogens
------------------------------------------------------------------------
Enteric virus Illness
------------------------------------------------------------------------
Poliovirus............................. Paralysis.
Coxsackievirus A....................... Meningitis, fever, respiratory
disease.
Coxsackievirus B....................... Myocarditis, congenital heart
disease, rash, fever,
meningitis, encephalitis,
pleurodynia, diabetes melitis,
eye infections.
Echovirus.............................. Meningitis, encephalitis, rash,
fever, gastroenteritis.
Norwalk virus and other caliciviruses.. Gastroenteritis.
Hepatitis A virus...................... Hepatitis.
Hepatitis E virus...................... Hepatitis.
Small round structured viruses Gastroenteritis.
(probably caliciviruses).
Rotavirus.............................. Gastroenteritis.
Enteric Adenovirus..................... Respiratory disease, eye
infections, gastroenteritis.
Astrovirus............................. Gastroenteritis.
------------------------------------------------------------------------
(Data from the 1994 Encyclopedia of Microbiology, Underlineindicates
disease causality rather than association)(Lederberg, 1992).
Bacterial Pathogens
Bacterial pathogens may be primary pathogens (those that can cause
illness in most individuals) or secondary or opportunistic pathogens
(those that primarily cause illness only in sensitive sub-populations).
Unlike most primary pathogens, some opportunistic bacterial pathogens
can colonize and grow in the biofilm in water system distribution
lines. Some waterborne bacterial agents cause disease by rapid growth
and dissemination (e.g., Salmonella) while others primarily cause
disease via toxin production (e.g., Shigella, E. coli O157,
Campylobacter jejuni). Campylobacter, E. coli and Salmonella have a
host range that includes both animals and humans; Shigella is
associated with humans and some other primates (Geldreich, 1996). As
noted previously, some waterborne bacterial pathogens can survive a
long time outside their hosts.
Most of the waterborne bacterial pathogens cause gastrointestinal
illness, but some can cause severe illness too. For example, Legionella
causes Legionnaires Disease, a form of pneumonia that has a fatality
rate of about 15%. It can also cause Pontiac Fever, which is much less
severe than Legionnaires Disease, but causes illness in almost everyone
exposed. A few strains of E. coli can cause severe disease, including
kidney failure. One strain, E. coli O157:H7 has caused several
waterborne disease outbreaks since 1990. It is a prime cause of bloody
diarrhea in infants, and can cause hemorrhagic colitis (severe
abdominal cramping and bloody diarrhea). In a small percentage of
cases, hemorrhagic colitis can lead to a life-threatening complication
known as hemolytic uremic syndrome (HUS), which involves destruction of
red blood cells and acute kidney failure. From 3% to 5% of HUS cases
are fatal (CDC, 1999), and most commonly found in young children and
the elderly. Some of the opportunistic pathogens can also cause a
variety of illnesses including meningitis, septicemia, and pneumonia
(Rusin et al., 1997).
Table II-8.--Some Illnesses Caused by Major Waterborne Bacterial
Pathogens
------------------------------------------------------------------------
Bacterial pathogen Illnesses
------------------------------------------------------------------------
Campylobacter jejuni................... Gastroenteritis, meningitis,
associated with reactive
arthritis and Guillain-Barre
paralysis.
Shigella species....................... Gastroenteritis, dysentery,
hemolytic uremic syndrome,
convulsions in young children,
associated with Reiters
Disease (reactive
arthropathy).
Salmonella species..................... Gastroenteritis, septicemia,
anorexia, arthritis,
cholecystitis, meningitis,
pericarditis, pneumonia,
typhoid fever.
[[Page 30213]]
Vibrio cholerae........................ Cholera (dehydration and kidney
failure).
Escherichia coli (several species)..... Gastroenteritis, hemolytic
uremic syndrome (kidney
failure).
Yersinia entercolitica................. Gastroenteritis, acute
mesenteric lymphadenitis,
joint pain.
Legionella species..................... Legionnaires Disease, Pontiac
Fever
------------------------------------------------------------------------
(Data from the 1994 Encyclopedia of Microbiology, Underline indicates
disease causality rather than association)(Lederberg, 1992).
E. Risk Estimate
1. Baseline Risk Characterization
This section provides an estimate of the number of people that may
be at risk of microbial illness associated with consumption of fecally
contaminated drinking water in populations served by ground water
systems. EPA has prepared estimates of the numbers of people at risk of
viral illness (and possibly death) from three conditions in which fecal
contamination may be introduced to ground water systems: fecal
contamination in the source water of systems without disinfection;
fecal contamination in the source water of systems with inadequate
(less than 4-log as discussed later) or failed disinfection; and fecal
contamination of the distribution system.
The first condition in which EPA characterizes the baseline risk is
for source contaminated ground water systems which do not have
disinfection treatment. EPA characterizes the risk to consumers in
these systems in five steps: (1) Calculating the population served by
undisinfected systems using ground water sources; (2) determining the
occurrence of the pathogens of concern in these systems; (3) assessing
the exposure to the pathogens of concern; (4) determining the
pathogenicity (likelihood of infection) based on dose-response
information for each of the pathogens characterized; and (5)
calculating the number of illnesses among the population served
resulting from consumption of water containing the pathogens.
EPA then estimates additional illnesses resulting from systems with
inadequate or failed disinfection treatment and fecally contaminated
source water, and systems in which fecal contamination is introduced
into the distribution system. These additional illnesses are estimated
based on the causes of contamination which lead to waterborne disease
outbreaks reported to the CDC in ground water systems from 1991 to
1996. To estimate these additional illnesses, EPA calculated the ratio
of the outbreak illnesses in systems with inadequate or failed
disinfection treatment to outbreak illnesses in systems without any
disinfection, and the ratio of outbreak illnesses in systems with
distribution system contamination to outbreak illnesses in systems
without any disinfection.
2. Summary of Basic Assumptions
This risk assessment uses a number of assumptions to arrive at an
estimate of the number of people at risk of illness or death due to
consumption of water from systems with fecal contamination. Some of
these assumptions are necessary because data in these areas simply does
not exist.
The feasibility of performing a risk analysis on each and every
microbial contaminant is diminished when considering the wide range of
different microbial contaminants that exist, and that detection methods
for all of these contaminants do not exist. Therefore, the risk
assessment assumes that the only people exposed to viral contamination
are the people served by those wells which test positive for the two
viruses used in the risk assessment model, and the exposed population
will be exposed to the virus concentration throughout the entire year.
The assumption that the population is exposed only to viruses which are
accurately described by the model viruses may lead to an
underestimation of exposure.
The model viruses which were chosen to act as surrogates for all
viruses fall into two categories; those viruses which have low-to-
moderate infectivity but relatively severe health effects, and those
viruses which have high infectivity but relatively mild health effects.
Exposure to viruses that do not fall into these categories may result
in an underestimate or overestimate of risk. Risks are not directly
quantified for bacterial contaminants because EPA does not have
sufficient data to directly model bacterial risk. However, EPA has
adjusted its risk estimate for viral illness to approximate for the
risk of bacterial illness.
The simplifying assumptions used in this risk assessment, as well
as assessing the exposure in only the positive wells, yields an
estimated average risk that EPA assumes is a best estimate of the
actual risk given available data.
3. Population Served by Untreated Ground Water Systems
EPA estimates there are 44,000 community ground water systems (CWS)
serving 88 million people; 19,000 non-transient, non-community ground
water systems (NTNCWS) serving five million people; and 93,000
transient non-community ground water systems (TNCWS) serving 15 million
people (SDWIS, 1997a). Of these systems, EPA estimates that 68% percent
of CWSs are disinfected (CWSS, 1997) (US EPA, 1997c). Larger CWSs are
more likely to practice disinfection than are smaller CWSs (e.g., 81%
of CWSs serving more than 100,000 people are disinfected while 45% of
systems serving less than 100 people disinfect. Estimates of treatment
for noncommunity water systems are not as detailed. However, based upon
information from State drinking water programs, EPA estimates 28% of
NTNCWS and 18% of TNCWS disinfect (US EPA, 1996a).
Based upon the number of people served by ground water systems, and
the percentage of systems which disinfect, EPA estimates that 18
million people are served untreated ground water from CWSs, four
million people are served untreated water from NTNCWSs, and 13 million
people are served untreated water from TNCWSs. There is a potential for
double or triple counting of the same people within these estimates
since a number of people may be served ground water from more than one
of the system type categories. For example, a person may consume water
from a CWS at home, and a NTNCWS at work or a TNCS while on vacation.
EPA has addressed the potential for double counting in the analysis by
assuming that individuals do not consume water from each system type
every day (see section V).
4. Pathogens Modeled
EPA is concerned about ground water systems which are fecally
contaminated since drinking water in these systems may contain
pathogenic viruses and/or bacteria. A wide number of viral and
bacterial pathogens have been associated with waterborne disease in
ground water systems. However, there are inadequate data for EPA to
[[Page 30214]]
characterize the risk attributable to each pathogen because detection
methods are not available for all pathogens. Additionally, detection
methods which are available may be insensitive and incapable of
detecting the presence of viruses at very low concentrations. However,
even at low concentrations, viruses in drinking water can result in
infection. To the extent that detection methods do not exist for a
particular pathogen, there may be a resultant underestimation of the
risk of illness and death.
In this analysis, EPA estimates the number of illnesses annually
associated with two types of pathogenic viruses found in fecally
contaminated ground water. These two types of viruses are designated as
Type A and Type B viruses for this analysis. Type A viruses represent
those viruses which are highly infective, yet have relatively mild
symptoms (e.g., gastroenteritis). For this analysis, rotavirus is used
as a surrogate for all Type A viruses because rotavirus has been
detected in drinking water sources, dose-response data have been
prepared for rotavirus and rotavirus has been implicated as the
etiologic agent in incidents of waterborne disease. Type B viruses
represent those viruses which have low-to-moderate infectivity, yet
have potentially more severe symptoms (e.g., myocarditis), and are
represented by echovirus. Echovirus also has available dose-response
data (Regli et al, 1991) and has been implicated in a waterborne
disease outbreak (Haefliger et al., 1998).
The risk assessment used model viruses as surrogates of the actual
viruses present. As a result, the risk assessment provides an
estimation of risks. The additional risks from other viruses may be
higher or lower depending on their occurrence or pathogenicity. For
example, if the risk assessment estimated the risks from exposure to
Norwalk virus (a Type A virus), using rotavirus as a surrogate, the
morbidity rate may be higher for adults than the rate assumed in the
model. An outbreak in an Arizona resort in 1989 was believed to be
caused by a Norwalk-like virus. This agent may have been responsible
for an outbreak which caused illness in 110 out of 240 guests of all
ages (Lawson et al, 1991), a 46% morbidity rate. This is much higher
than the morbidity rate of 10% for Type A virus among people older than
two. National occurrence data do not exist for many of the other
pathogens that may occur in drinking water; therefore, EPA has limited
its estimation of risk to only those viral pathogens for which
occurrence data and dose response data are available.
Occurrence studies show a significant occurrence of bacterial
indicators in ground water wells; for example, almost 9% percent of the
wells sampled in the AWWARF study tested positive for the presence of
enterococci (Abbaszadegan et al., 1999). However, EPA cannot directly
estimate national illnesses from bacterial pathogens such as
Salmonella, due to a lack of occurrence data for those pathogens. EPA
believes that the majority of waterborne illnesses due to unknown
etiological agents are caused by viruses because viruses move more
readily in the ground, remain viable longer and are more infectious
than bacteria. Also, more methodologies exist for the identification of
bacterial pathogens than for viral pathogens and therefore bacterial
pathogens are more likely to be identifiable. The CDC data shows that
for every 100 viral or unknown etiological agent illnesses there were
20 bacterial illnesses. Therefore, EPA estimates that the number of
viral illnesses can be increased by 20% to account for bacterial
illnesses in ground water systems.
5. Microbial Occurrence and Concentrations
EPA reviewed the ground water viral occurrence data (see discussion
of occurrence studies in section II. C.) to develop estimates of: the
portion of ground water sources which are contaminated with viruses,
the period of time in which the wells are contaminated, and the
concentration of viruses within the contaminated wells. EPA believes
that improperly constructed wells may have significantly higher virus
occurrence and concentrations than properly constructed wells (wells
which do not comply with State well construction codes). Improperly
constructed wells are likely to have more pathways for the introduction
of viruses and less natural filtration by the overlying hydrogeologic
material. Therefore, the exposure and risks from consumption of water
from improperly constructed wells will most likely be higher. As a
result, the exposure and risks should be assessed separately for
properly and improperly constructed wells in order to develop a range
reflecting national conditions.
EPA determined that the study conducted by AWWARF represents
conditions in properly constructed wells and the EPA/AWWARF (Lieberman
et al., 1994, 1999) study represents conditions in improperly
constructed wells. EPA selected the AWWARF study as representative of
properly constructed wells (e.g., wells with casing and grout to
confining layers, sanitary seals, etc.) because it excluded wells of
improper construction and the wells sampled were representative of
hydrogeologic conditions for water supply wells in the United States.
However, the wells selected may not have been representative of the
probability of fecal contamination in ground water wells nationally. As
noted in section II.C.1., one-third of the wells in this study were
originally selected for the purpose of evaluating the effectiveness of
the PCR method based on criteria that may over represent high risk
wells. The remaining two-thirds were selected to balance the sample
with wells that were representative of hydrogeologic conditions for
drinking water wells nationally. EPA requests comment and data which
would help assess the representativeness of the wells in the AWWARF
study sample. However, EPA believes that the AWWARF study data
represents the best currently available data on occurrence of viral
pathogens in properly constructed wells and has thus used it as the
basis of baseline incidence estimates.
EPA selected the EPA/AWWARF study to be representative of wells of
improper construction because it sampled wells which were determined to
be vulnerable to contamination. The EPA/AWWARF study considered wells
as vulnerable based on one or more of the following considerations:
hydrogeology, well construction, State nominations, microbial sampling
results, close proximity to known sources of fecal contamination, and
water quality history. For the purposes of the risk assessment, all
wells determined to be vulnerable were used as surrogates for
improperly constructed wells. The results from this study may over
estimate the risks from improperly-constructed wells generally, since
it included only wells that were deliberately selected through a
several step process to be highly vulnerable to contamination (see
section II.C.2.). EPA estimated that 83% of systems have properly
constructed wells based upon data from ASDWA's Survey of Best
Management Practices for Community Ground Water Systems (ASDWA, 1998).
The AWWARF study data include viral cell culture assay results
which detect the presence of viable enterovirus (including echovirus
and other Type B viruses) in the samples. Twenty-one of the 442 wells
sampled (4.8%) tested positive for the Type B viral cell culture. EPA
determined that this data can be used to estimate the percentage of
properly constructed wells which are contaminated at a given point in
time with Type B viruses. The AWWARF
[[Page 30215]]
study data also include rotavirus PCR results which indicate that 62 of
the 425 (14.6%) wells sampled contained rotavirus genetic material. EPA
determined that the PCR results may be an overestimation of the portion
of wells with viable Type A viruses since PCR methods do not
distinguish between viable and non-viable viruses. To calculate the
portion of PCR positive wells which contain viable viruses EPA compared
the enterovirus (Type B) cell culture results to the enterovirus (Type
B) PCR analysis and found that for every enterovirus cell culture
positive well, there were 3.3 PCR enterovirus positive wells. EPA
estimated that the 1/3.3 rotavirus PCR wells contained viable virus,
and therefore 4.4% (14.6%/3.3) of all properly constructed wells were
contaminated with Type B viruses at any one time. Viral and bacterial
indicator data indicate there are a greater percentage of wells in the
study which were fecally contaminated than contained the viral
pathogens at the time of sampling. For example, almost 16% of all wells
tested positive for viral cell culture, male specific coliphage or
enterococci.
The EPA/AWWARF study sampled wells vulnerable to contamination
monthly for a one year period and found that 6.0% of the samples tested
positive for enterovirus (Type B) cell culture. Since cell culture
methods are not available for rotavirus (the representative of Type A
viruses), the EPA/AWWARF study tested samples using PCR methods for the
presence of rotavirus to estimate the occurrence of Type A viruses in
improperly constructed wells. However, the PCR data is still under
review by researchers and unavailable for consideration in this
analysis. EPA therefore based the estimate of occurrence of viable Type
A viruses in improperly constructed wells on the ratio of viable Type A
virus in the AWWARF study (4.4%) to Type B viruses in the AWWARF study
(4.7%). Applying this ratio (4.4%/4.7%) to the percentage of improperly
constructed wells containing Type B viruses (6.0%), EPA estimates the
percentage of improperly constructed wells with Type A virus
contamination is 5.5%.
EPA estimated Type A and Type B virus concentrations are 0.36
viruses/100L for properly constructed wells based on the mean
enterovirus concentration in the AWWARF study. EPA also estimated Type
A and Type B virus concentrations to be 29 viruses/100L for improperly
constructed wells based on the mean enterovirus concentration in EPA/
AWWARF study. Although these studies determined the concentrations of
enteroviruses (Type B viruses) only, for the purposes of this analysis
EPA assumed the concentrations of Type A viruses and Type B viruses
were equivalent.
6. Exposure to Potentially Contaminated Ground Water
EPA developed estimates of the population potentially exposed to
viral pathogens based upon the estimates of population served by
undisinfected systems and the portions of those systems which are
estimated to be virally contaminated. In CWS, 18 million people are
served undisinfected ground water. Assuming 17% of wells serving these
people are improperly constructed (and 83% are properly constructed)
from the results of the ASDWA BMP Survey (ASDWA, 1997), and Type A
viruses occur in 4.4% of properly constructed wells and 5.5% of
improperly constructed wells, the population potentially exposed to
Type A viruses in CWS is 842,000. Similar calculations can be conducted
to obtain the population exposed to Type A viruses in NTNCWS, as well
as Type B viruses in all ground water systems. EPA's estimates of the
population potentially exposed to the viruses are presented in Table
II-9. Many of the people exposed to the Type A viruses are also exposed
to the Type B viruses, therefore these number cannot be added.
Table II-9.--Population Potentially Exposed to Virally Contaminated
Drinking Water in Undisinfected Ground Water Systems
------------------------------------------------------------------------
Population Population
potentially potentially
System type exposed to exposed to
type A virus type B virus
------------------------------------------------------------------------
CWS..................................... 842,000 918,000
NTNCWS.................................. 175,000 191,000
TNCWS................................... 567,000 619,000
------------------------------------------------------------------------
To estimate the risk of illness from consumption of undisinfected
ground water, EPA estimated people consume an average 1.2 liters of
water per day based upon the 1994-1996 USDA Continuing Survey of Food
Intakes by Individuals (US EPA, 2000a). EPA accounted for the
variability in consumption by modeling consumption as a custom
distribution fit to age groups in the survey data. EPA also assumed
that people consume water from CWSs 350 days per year; from NTNCWSs 250
days per year; and from TNCWSs 15 days per year. EPA notes that these
assumptions may allow for some double counting of exposure, but EPA is
not aware of data to allow a more refined breakdown of consumption. EPA
requests comment on these assumptions.
7. Pathogenicity
After estimating the population potentially exposed to untreated
(i.e., not disinfected) contaminated ground water and the amount of
water consumed, the next step is to assess the pathogenicity of the
viruses. Once viruses are consumed, the likelihood of infection and
illness varies depending on the virus.
For this analysis, the likelihood of infection from ingestion of
one or more Type A or Type B viruses are estimated based on dose
response equations developed for rotavirus (Ward et al., 1986) and
echovirus (Schiff et al., 1984), respectively. These equations estimate
the annual probability of infection following consumption of a
specified virus and are based on studies of healthy volunteers. The
volunteers for these studies are typically between the ages of 20 and
50, and therefore, may underestimate the probability of infection in
sensitive subpopulations (e.g., children and elderly) and the
immunocompromised (e.g., nursing home residents and AIDS patients).
Rotavirus dose-response information was used to represent Type A
viruses, while echovirus dose-response information was used to
represent Type B viruses.
Once a person becomes infected, the likelihood of illness
(morbidity) varies, depending on the pathogen and the sensitivity of
the consumer. For Type A viruses, EPA assumed the percent of people
becoming ill once infected is 88% for children under the age of two
(Kapikian and Chanock, 1996). EPA assumed a morbidity rate of 10% for
all other populations based upon a study of a rotavirus outbreak
(Foster et al., 1980) and incidents of rotavirus in families with
infants ill with rotavirus (Wenman et al., 1979).
EPA assumed the percent of people infected with Type B viruses who
become ill also varies with age: 50% for children five years of age and
less, 57% for individuals between 5 and 16 years of age, and 33% for
people older than 16. EPA estimated these age-specific morbidity values
based on data from a community-wide echovirus type 30 epidemic (Hall et
al., 1970) and from the New York Viral Watch (Kogon et al., 1969).
Secondary illnesses result from individuals being exposed to
individuals who contracted the illness from drinking water. For this
analysis, EPA estimates the additional number of
[[Page 30216]]
people who become ill as a result of secondary spread. For Type A
viruses, EPA assumed that an additional 0.55 people will become ill
from every child that becomes ill through consumption of drinking
water. This assumption is based on a study of children under five years
old, ill with rotavirus, who spread the illness to others in their
households (Kapikian and Chanock, 1996). For Type B viruses EPA assumed
that 0.35 additional people will become ill through secondary spread.
This assumption was based on a review of various epidemiological
studies for echovirus (Morens et al., 1991). There is some uncertainty
as to the exact rate of secondary spread for Type B viruses, so EPA has
assumed that the secondary spread rates range from 0.11 to 0.55.
The probability that an ill person will die as a result of an
illness is referred to as mortality. EPA expects Type A viruses to
result in far fewer deaths than Type B viruses. EPA assumed a mortality
rate for all age groups of 0.00073 percent. This assumption was based
on an estimate of 20 rotavirus deaths per year out of 2,730,000 cases
of rotavirus diarrhea in children 0-4 years old (Tucker et al., 1998).
EPA assumed the mortality rate for Type B viruses be 0.92 percent for
infants one month or less. This assumption was based upon studies of
hospitalized infants (Kaplan and Klein, 1983). For the rest of the
population, EPA assumed that 0.04 percent of people ill from Type B
viruses will die. These estimates may underestimate the number of
infant deaths due to Type B viral illnesses, since Jenista et al.
(1984) and Modlin (1986) reported a three percent case fatality rate
for infants (one month or less) which is three times the value used in
the model.
8. Potential Illnesses
EPA estimates, based upon the assumptions described earlier, that
98,000 viral illnesses each year are caused by consuming drinking water
in undisinfected public ground water systems. EPA further estimates
that nine of these people die each year.
EPA believes there are additional waterborne illnesses and deaths
among consumers of drinking water from public ground water systems
beyond those estimated due to contaminated source waters in
undisinfected systems. Between 1991 and 1996 there were 1,260
waterborne outbreak illnesses reported to CDC which were attributed to
microbial contamination of the source and inadequate or interrupted
disinfection, and 944 waterborne illnesses reported to CDC which were
attributed to distribution system contamination in ground water
systems. In that same period there were 2,924 reported outbreak
illnesses in source contaminated undisinfected system. This results in
0.43 (1,260/2,924) additional illnesses in source contaminated, ground
water systems with failed disinfection for every illness from
undisinfected, fecally contaminated ground water. Based on similar
analysis, there are also 0.32 (944/2,924) additional illnesses due to
distribution system contamination for every one illness due to source
contamination in undisinfected ground water systems. (This ratio does
not apply to transient noncommunity water systems, because they do not
have distribution systems.) EPA assumed the ratios of the causes of
reported outbreak illnesses is equal to the ratio of the causes of all
waterborne illnesses. Therefore, EPA estimates, based upon these
ratios, that an average of 42,000 additional illnesses and four
additional deaths occur each year as a result of source contamination
and inadequate or interrupted disinfection. EPA also estimates that an
average of 28,000 additional illnesses and three additional deaths are
caused each year by distribution system contamination. Table II-10
presents the estimates of viral illness and death under current
conditions.
Table II-10.--Estimates of Baseline Viral Illness and Death Due to Contamination of Public Ground Water Systems
--------------------------------------------------------------------------------------------------------------------------------------------------------
No. of type A No. of type B total
Cause of contamination virus No. of type A virus No. of type B illnesses Total deaths
illnesses virus deaths illnesses virus deaths types A & B types A & B
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source contamination/undisinfected system............... 78,000 1 20,000 8 98,000 9
Source contamination/disinfected system................. 34,000 .............. 8,000 4 42,000 4
Distribution system contamination....................... 22,000 .............. 6,000 3 28,000 3
-----------------------------------------------------------------------------------------------
All Causes.......................................... 134,000 1 34,000 14 168,000 16
--------------------------------------------------------------------------------------------------------------------------------------------------------
Because of a lack of occurrence data for bacterial pathogens in
ground water, risks from bacterial contamination of ground water
sources and distribution systems are not quantified in this assessment.
Although it is believed that viruses are more readily transported
through the subsurface than bacteria (Sinton et al., 1997), ground
water system disease outbreaks caused by bacterial pathogens such as
Shigella, Salmonella spp., and Campylobacter spp. and E. coli O157:H7
have been reported. For the period 1971-1996, 56 outbreaks, resulting
in more than 10,000 illnesses and 11 deaths, were attributed to
bacterial pathogen contamination of public ground water systems. More
than 20% of these bacterial outbreaks occurred since 1991, and several
outbreaks were attributed to gross fecal contamination of distribution
lines.
As previously stated, there may be an additional 20% of illnesses
caused by bacterial pathogens (in the absence of viral pathogens) in
fecally contaminated ground water. Therefore, the numbers of illnesses
and deaths presented in Table II-10 may underestimate the true numbers
of annual illnesses and deaths by 20% (an estimated 34,000 additional
illnesses and three additional deaths).
9. Summary of Key Observations
In conclusion, EPA believes that at any one point in time (most
approximately 90 percent) ground water systems provide uncontaminated
water. However, the risk characterization described herein indicates
that a subset of ground water systems represent a potential risk to
public health, which clearly supports the need to proceed with
regulation of these systems. According to the assessment, EPA estimates
that approximately 168,000 people are at risk to viral illness and 16
people are at risk of death, annually. It is noted that this analysis
focuses primarily on the potential of gastrointestinal illness caused
by exposure to viruses, therefore; the potential for additional
illnesses from ground water contaminated only by pathogenic bacteria
also exists and may account for an additional 34,000 illnesses and
three deaths annually.
[[Page 30217]]
Therefore, the estimate of illnesses represents a potential
underestimate of the actual illnesses attributed to consumption of
water from ground water systems. Based on this analysis EPA believes
that risk of microbial illness exists for a substantial number of
people served by ground water systems. Consequently, EPA believes that
the proposed regulatory provisions discussed later provide a meaningful
opportunity for public health risk reduction.
10. Request for Comments
EPA seeks comment on the data, criteria and methodology used in the
risk assessment, and where any different approaches may be appropriate.
EPA also seeks comment on the assumptions used in this assessment, as
well as the conclusions reached, and any additional data that
commenters may be able to provide on occurrence, exposure, infectivity,
morbidity, or mortality associated with microbial pathogens in ground
water.
F. Conclusion
In EPA's judgment, the data and information presented in previous
sections relating to outbreaks, occurrence, adverse microbial health
effects, exposure, and risk characterization demonstrate that there are
contaminants of concerns that exist in ground water at levels and at
frequencies of public health concern. Moreover, as discussed in detail
later, the Agency believes there are targeted risk-based regulatory
strategies that provide a meaningful opportunity to reduce public
health risk for a substantial number of people served by ground water
sources.
EPA recognizes that there are particular challenges associated with
developing an effective regulatory approach for ground water systems.
These include first, the large number of ground water systems; second,
the fact that only a subset of these systems appear to have microbial
contamination (although a larger number are likely to be vulnerable);
and third, that most ground water systems range from being small to
very small in terms of population served. These factors combine to
underscore the fact that a one-size-fits-all approach cannot work. This
point was made repeatedly by participants in public stakeholder
meetings across the country, and EPA agrees. The task therefore is to
develop a protective public health approach which ensures a baseline of
protection for all consumers of ground water and sets in place an
increasingly targeted strategy to identify high risk or high priority
systems that require greater scrutiny or further action.
III. Discussion of Proposed GWR Requirements
The information outlined earlier indicates that the primary causes
of waterborne related illnesses are associated with source water
contamination and untreated ground water, source water contamination
and unreliable treatment, water system deficiencies, and a subset of
waterborne disease outbreaks of unknown causes. The requirements and
options proposed today address each of these areas through a multiple-
barrier approach which relies upon five major components: periodic
sanitary surveys of ground water systems requiring the evaluation of
eight elements and the identification of significant deficiencies;
hydrogeologic assessments to identify wells sensitive to fecal
contamination; source water monitoring for systems drawing from
sensitive wells without treatment or with other indications of risk; a
requirement for correction of significant deficiencies and fecal
contamination through the following actions: eliminate the source of
contamination, correct the significant deficiency, provide an
alternative source water, or provide a treatment which achieves at
least 99.99 percent (4-log) inactivation or removal of viruses, and
compliance monitoring to insure disinfection treatment is reliably
operated where it is used.
A. Sanitary Surveys
1. Overview and Purpose
A key element of the multiple-barrier approach is periodic
inspection of ground water systems through sanitary surveys. According
to the Total Coliform Rule (TCR), a sanitary survey is an onsite review
of the water source, facilities, equipment, operation and maintenance
of a public water system for the purpose of evaluating the adequacy of
such source, facilities, equipment, operation and maintenance for
producing and distributing safe drinking water (40 CFR 141.2). The
Agency believes that periodic sanitary surveys, along with appropriate
corrective actions, are indispensable for assuring the long-term
quality and safety of drinking water. When properly conducted, sanitary
surveys can provide important information on a water system's design
and operations and can identify minor and significant deficiencies for
correction before they become major problems. By taking steps to
correct deficiencies exposed by a sanitary survey, the system provides
an additional barrier to microbial contamination of drinking water.
The Agency proposes the following sanitary survey requirements: (1)
States, or authorized agents, conduct sanitary surveys for all ground
water systems at least once every three years for CWSs and at least
once every five years for NCWSs; (2) sanitary surveys address all eight
elements set out in the EPA/State Joint Guidance on sanitary surveys
(outlined later in this section); (3) States provide systems with
written notification which describes and identifies all significant
deficiencies no later than 30 days of the on-site survey; and (4)
systems consult with the State and take corrective action for any
significant deficiencies no later than 90 days of receiving written
notification of such deficiencies, or submit a schedule and plan to the
State for correcting these deficiencies within the same 90 day period;
and (5) States must confirm that the deficiencies have been addressed
within 30 days after the scheduled correction of the deficiencies.
A ground water system that has been identified as having
significant deficiencies must do one or more of the following:
eliminate the source of contamination, correct the significant
deficiency, provide an alternate source water, or provide a treatment
which reliably achieves at least 99.99 percent (4-log) inactivation or
removal of viruses before or at the first customer. Ground water
systems which provide 4-log inactivation or removal of viruses will be
required to conduct compliance monitoring to demonstrate treatment
effectiveness. The ground water system must consult with the State to
determine which of the approaches, or combination of approaches, are
appropriate for meeting the treatment technique requirement. Ground
water systems unable to address the significant deficiencies in 90
days, must develop a specific plan and schedule for meeting this
treatment technique requirement, submit them to the State, and receive
State approval before the end of the same 90-day period. For the
purposes of this paragraph, a ``significant deficiency'' includes, : a
defect in design, operation, or maintenance, or a failure or
malfunction of the sources, treatment, storage, or distribution system
that the State determines to be causing, or has the potential for
causing the introduction of contamination into the water delivered to
consumers.
Sanitary surveys provide a comprehensive and accurate record of the
components of water systems, assess the operating conditions and
adequacy of the water system, and determine if
[[Page 30218]]
past recommendations have been implemented effectively. The purpose of
the survey is to evaluate and document the capabilities of the water
system's sources, treatment, storage, distribution network, operation
and maintenance, and overall management in order to ensure the
provision of safe drinking water. In addition, sanitary surveys provide
an opportunity for State drinking water officials or approved third
party inspectors to visit the water system and educate operators about
proper monitoring and sampling procedures, provide technical
assistance, and inform them of any changes in regulations.
Sanitary surveys have historically been conducted by State drinking
water programs as a preventative tool to identify water system
deficiencies that could pose a threat to public health. In 1976, EPA
regulations established, as a condition of primacy, that States develop
a systematic program for conducting sanitary surveys, with priority
given to public water systems not in compliance with drinking water
regulations (40 CFR 142.10 (b)(2)). This primacy requirement did not
define the scope of sanitary surveys or specify minimum criteria.
In 1989, the TCR included a provision that requires systems that
serve 4,100 people or less and collecting fewer than five routine total
coliform samples per month to conduct a periodic sanitary survey every
five years, with an exception made for NCWS that use protected and
disinfected ground water to conduct the survey every ten years. The
TCR, however, does not establish what must be addressed in a sanitary
survey or how such a survey should be conducted. The responsibility is
on the system rather than the State for completing the sanitary survey
(40 CFR 141.21(d)(2)). The TCR requires systems to use either a State
official or an agent approved by the State to conduct the sanitary
survey.
The IESWTR (63 FR 69478, December 16, 1998), established
requirements for primacy States to conduct sanitary surveys for all
systems using surface water or ground water under the direct influence
of surface water. The rule also requires States to have the appropriate
authority for ensuring that systems address significant deficiencies.
The State must perform a survey at least once every three years for
CWSs and every five years for NCWSs. These surveys must encompass the
eight major areas defined by the EPA/State Joint Guidance (discussed in
section 3).
This GWR proposal and the IESWTR differ in the requirements for a
system to correct any significant deficiency. In the IESWTR, States are
specifically required to have the appropriate rules or other authority
to require systems to respond in writing to significant deficiencies
outlined in a sanitary survey report within at least 45 days. A system,
under this 45-day time frame, is required to notify the State in
writing how and on what schedule it will address significant
deficiencies noted in the survey. This GWR proposal differs from the
IESWTR by proposing to require ground water systems to correct
significant deficiencies and to do so within 90 days or seek a State
approved schedule for plans requiring longer than 90 days.
2. General Accounting Office Sanitary Survey Investigation
In 1993, the US General Accounting Office (US GAO) investigated
State sanitary survey practices. The US GAO found that many sanitary
surveys were deficient, and that follow-up on major problems was often
lacking. This investigation, which is described next, was published as
a report, Key Quality Assurance Program is Flawed and Underfunded (US
GAO 1993).
US GAO was directed by Congress to review State sanitary survey
programs due to congressional concern that many States were cutting
back on these programs, and thus undermining public health. Congress
asked US GAO to determine in its report whether sanitary surveys are
comprehensive enough to determine if a water system is providing safe
drinking water and what the results indicate about water systems
nationwide.
As part of this effort, GAO sent a detailed questionnaire to 49
States to attain a nationwide perspective on whether the States were
conducting sanitary surveys, the frequency and comprehensiveness of the
surveys, and what the survey results indicate about the operation and
condition of water systems. To obtain more detailed information, the
GAO also focused on 200 specific sanitary surveys conducted on CWSs in
four States (Illinois, Montana, New Hampshire and Tennessee). This
information was summarized in the GAO's report (US GAO 1993). The GAO
report presented a number of key concerns, as discussed next.
Frequency Varies Among States and is Declining Overall. At least 36
States had a policy to conduct surveys of CWSs at intervals of three
years or less; however, only 21 of these States were conducting surveys
at this frequency. The remaining 15 States reported they were unable to
implement this policy because their inspectors had other competing
responsibilities that often took precedence over non-mandated
requirements (e.g., sanitary surveys). Overall, the frequencies of the
surveys vary from quarterly to 10 years. According to the report,
States have reduced the frequency of surveys since 1988, a downward
trend that is expected to continue.
Comprehensiveness of Sanitary Surveys is Inconsistent. The report
indicates that a comprehensive sanitary survey, as recommended in
Appendix K of EPA's SWTR Guidance Manual (US EPA, 1990b), is frequently
not conducted. Forty-five out of 48 States omitted one or more key
elements defined in the 1990 guidance manual. The GAO noted wide
variation among States in the comprehensiveness of their sanitary
surveys. Some States, for example, omit inspections of water
distribution systems and/or other key components or operations of water
systems, others do not provide complete documentation of sanitary
survey results. Based on a review of the 200 sanitary surveys, survey
results which identify deficiencies were found to be inconsistently
interpreted from one surveyor to another. In some cases, systems'
deficiencies that could have been detected during a comprehensive
survey may not be found until after water quality is affected and the
root cause(s) investigated. By that time, however, consumers may
already have ingested contaminated water (US GAO, 1993).
Limited Efforts to Ensure that Deficiencies are Corrected. The GAO
found that follow-up procedures for deficiencies were weak. The
detailed review of the four States' sanitary surveys indicated that
deficiencies frequently go uncorrected. Of the 200 surveys examined,
about 80% disclosed deficiencies and 60% cited deficiencies that had
already been identified in previous surveys. Of particular concern was
the GAO finding that smaller systems (serving 3,300 or less) are in
greatest need of improvements. Small systems compose a significant
majority of all ground water systems. Ninety-nine percent
(approximately 154,000) of ground water systems serve fewer than 10,000
people and ninety-seven percent (approximately 151,000) serve 3,300 or
fewer people.
Results Poorly Documented. The GAO also found variation in how
States document and interpret survey results. Proper documentation
would facilitate follow-up on the problems detected.
GAO recommended EPA work with States to establish minimum criteria
on how surveys should be conducted and documented and to develop
procedures
[[Page 30219]]
to ensure deficiencies are corrected. This proposal addresses these
recommendations.
3. ASDWA/EPA Guidance on Sanitary Surveys
Recognizing the essential role of sanitary surveys and the need to
define the broad areas that all sanitary surveys should cover, EPA and
ASDWA prepared a joint guidance on sanitary surveys entitled EPA/State
Joint Guidance on Sanitary Surveys (1995). The guidance identified the
following eight broad components that should be covered in a sanitary
survey: source, treatment, distribution system, finished water storage,
pumps and pump facilities and controls, monitoring/reporting/data
verification, water system management and operations, and operator
compliance with State requirements. The EPA/State Joint Guidance does
not provide detailed instructions on evaluating criteria under the
eight elements; however, EPA has recently issued detailed supplementary
information as technical assistance (April 1999, Guidance Manual for
Conducting Sanitary Surveys of Public Water Systems)(US EPA, 1999e).
--Source. The water supply source is the first opportunity for
controlling contaminants. The reliability, quality, and quantity of the
source should be evaluated during the sanitary survey using available
information including results of source water assessments or other
relevant information. A survey should assess the potential for
contamination from activities within the watershed as well as from the
physical components and condition of the source facility.
--Treatment. The treatment phase should consider evaluation of the
handling, storage, use and application of treatment chemicals if the
system includes application of any chemicals. A review of the treatment
process should include assessment of the operation, maintenance, record
keeping and management practices of the treatment system.
--Distribution System. Given the potential for contamination to spread
throughout the distribution system, a thorough inspection of the
distribution network is important. Review of leakage that could result
in entrance of contaminants, monitoring of disinfection residual,
installation and repair procedures of mains and services, as well as an
assessment of the conditions of all piping and associated fixtures are
necessary to maintain distribution system integrity.
--Finished Water Storage. A survey of the storage facilities is
critical to ensuring the availability of safe water, and the adequacy
of construction and maintenance of the facilities.
--Pumps/Pump Facilities and Controls. Pumps and pump facilities are
essential components of all water systems. A survey should verify that
the pump and its facilities are of appropriate design and properly
operated and maintained.
--Monitoring/Reporting/Data Verification. Monitoring and reporting are
needed to determine compliance with drinking water provisions, as well
as to verify the effectiveness of source protection, preventative
maintenance, treatment, and other compliance-related issues regarding
water quality or quantity.
--Water System Management/Operations. The operation and maintenance of
any water system is dependent on effective oversight and management. A
review of the management process should ensure continued and reliable
operation is being met through adequate staffing, operating supplies,
and equipment repair and replacement. Effective management also
includes ensuring the system's long-term financial viability.
--Operator compliance with State requirements. A system operator plays
a critical role in the reliable delivery of safe drinking water.
Operator compliance with State requirements includes state-specific
operation and maintenance requirements, training and certification
requirements, and overall competency with on-site observations of
system performance.
4. Other Studies
As previously described (see section I.D.2.), ASDWA examined 28
different BMPs to determine the effectiveness of each BMP in
controlling microbial contamination. Within this study, 91.4% of
systems surveyed had implemented a sanitary survey within the previous
five years. The ASDWA survey found no significant association with
systems that conducted sanitary surveys and no total coliform
detections. The insignificance of the association between sanitary
surveys and the detection of bacteria may be due to the fact that State
sanitary surveys are designed to identify problems (ASDWA, 1998).
However, correction of sanitary survey deficiencies was correlated with
lower levels of total coliform, fecal coliform, and E. coli.
EPA conducted a survey published in Ground Water Disinfection and
Protective Practices in the United States (US EPA 1996a), which
confirmed the GAO finding that considerable variability among States
exists with regard to the scope and comprehensiveness of sanitary
surveys.
The Environmental Law Reporter (ELR), a private database of State
and Federal statutes and regulations, provides some information on
current State regulations for ground water systems. According to the
ELR, only the State of Washington does not require sanitary surveys
under the TCR requirement at 40 CFR 141.21(d). However, most State
regulations found in the ELR are general in nature and do not
specifically address the eight EPA/State Joint Guidance sanitary survey
components. State regulations vary considerably in terms of types of
systems surveyed, the content of the survey, and who is designated to
conduct the surveys (e.g., a sanitarian). The database indicates that
the majority of States (46 out of 50) do not specifically require
systems to correct deficiencies. Significantly, a number of States do
not appear to have legal authority to require correction of
deficiencies. The ELR findings contained in the Baseline Profile
Document for the Ground Water Rule (US EPA, 1999f) indicate that many
sanitary survey provisions do not appear in State regulations. The GAO
report confirmed that many States incorporated sanitary survey
requirements into policy, thereby undercutting their legal
enforceability.
5. Proposed Requirements
EPA proposes to require periodic State sanitary surveys for all
ground water systems specifically addressing all of the applicable
sanitary survey elements noted earlier, regardless of population size
served.
With regard to the frequency of sanitary surveys, EPA proposes to
require the State or a state-authorized third party to conduct sanitary
surveys for all ground water systems at least once every three years
for CWSs and at least once every five years for NCWSs. This approach
would be consistent with the requirements of the IESWTR. CWSs would be
allowed to follow a five-year frequency if the system either treats to
4-log inactivation or removal of viruses or has an outstanding
performance record in each of the applicable eight areas documented in
previous inspections and has no history of TCR MCL or monitoring
violations since the last sanitary survey. A State must, as part of its
primacy application, include how it will decide whether a system has
outstanding performance and is thus eligible for sanitary surveys at a
reduced frequency.
[[Page 30220]]
The Agency believes that periodic sanitary surveys, along with
appropriate corrective measures, are indispensable for ensuring the
long-term safety of drinking water. By taking steps to correct
deficiencies exposed by a sanitary survey, the system provides an
additional barrier to pathogens entering the drinking water.
The definition of a sanitary survey used in the GWR differs from
the definition of a sanitary survey in 40 CFR 141.2 by a parenthetical
clause. For the purpose of Subpart S, a sanitary survey is ``an onsite
review of the water source (identifying sources of contamination by
using results of source water assessments or other relevant information
where available), facilities, equipment, operation, maintenance and
monitoring compliance of a public water system to evaluate the adequacy
of the system, its sources and operations and the distribution of safe
drinking water.'' This reflects a recommendation by the 1997 M/DBP
Federal Advisory Committee Act that sanitary inspectors should use
source water assessments and other information where available as part
of the overall evaluation of systems. This change in definition
reflects the value of Source Water Assessment and Protection Programs
(SWAPPs) required by Congress in the 1996 SDWA amendments and the
importance of utilizing information generated as a result of that
activity.
EPA is also proposing to require that State inspectors, as part of
each sanitary survey, evaluate all applicable components defined in the
EPA/State Joint Guidance on Sanitary Surveys and identify any
significant deficiencies. Some stakeholders have suggested the
comprehensiveness of sanitary surveys be tailored based upon system
size and type. EPA requests comment on whether this would be an
appropriate approach and if so, what factors or criteria should be
considered in tailoring the scope or complexity of the sanitary survey.
Individual components of a sanitary survey may be separately
completed as part of a staged or phased State review process as part of
ongoing State inspection programs within the established frequency
interval. In its primacy package, a State which plans to complete the
sanitary survey in such a staged or phased review process must indicate
which approach it will take and provide the rationale for the specified
time frames for sanitary surveys conducted on a staged or phased
approach basis.
EPA proposes to regard the requirements for sanitary surveys under
the GWR as meeting the requirements for sanitary surveys under the TCR
(40 CFR 141.21). The reason for this is that the frequency and criteria
of a sanitary survey under the GWR is more stringent than that for the
TCR. For example, the TCR does not define a sanitary survey as
precisely as the GWR, which requires an evaluation of eight elements.
In addition, the frequency of the sanitary survey under the TCR for
CWSs is every five years, compared to three years (at least initially)
under the GWR. Also, the TCR requires a survey every ten years for
disinfected NCWSs using protected ground waters, as compared to every
five years under the GWR. The scope of the systems that must conduct a
sanitary survey also differs; under the TCR only systems that collect
fewer than five routine samples per month and serve less than 4,100
persons are required to undergo a sanitary survey, compared to all
ground water systems under the GWR. Given that the proposed sanitary
survey requirements under the GWR are more stringent than those under
the TCR, EPA notes that a survey under the TCR cannot replace one
conducted under the GWR, unless that survey meets the criteria
specified in the GWR.
As part of today's rule, a ``significant deficiency'' as identified
by a sanitary survey includes: A defect in design, operation, or
maintenance, or a failure or malfunction of the sources, treatment,
storage, or distribution system that the State determines to be
causing, or has the potential for causing the introduction of
contamination into the water delivered to consumers. This is a working
definition developed by the EPA GWR workgroup.
The Agency proposes to require the State to provide the system with
written notification which identifies and describes any significant
deficiencies found in a sanitary survey no later than 30 days after
completing the on-site survey. States would not be required, in this
rule, to provide the system with a complete sanitary survey report
within the 30 days of completing the on-site survey. Rather, this rule
requires that, at a minimum, the State provide the system a written
list which clearly identifies and describes all significant
deficiencies as identified during the on-site survey.
EPA proposes to require a system to: (1) Correct any significant
deficiencies identified in a sanitary survey as soon as possible, but
no later than 90 days of receiving State written notification of such
deficiencies, or (2) to submit a specific schedule and receive State
approval on the schedule for correcting the deficiencies within the
same 90-day period. The system must consult the State within this 90-
day period to determine the corrective action approach appropriate for
that system, consistent with the State's general approach outlined in
their primacy package. In performing a corrective action, the system
must eliminate the source of contamination, correct the significant
deficiency, provide an alternate source water, or provide a treatment
which reliably achieves at least 99.99 percent (4-log) inactivation or
removal of viruses before or at the first customer. Ground water
systems which provide 4-log inactivation or removal of viruses will be
required to conduct compliance monitoring to demonstrate treatment
effectiveness. There are cases in which one or more of the corrective
actions listed previously may be inappropriate for the nature of the
problem, and in these cases only appropriate corrective actions must be
taken. For example, a system with a significant deficiency in the
distribution system should not install treatment at the source water as
the corrective action; that system should correct the problem in the
distribution system. There may also be fecal sources that a State does
not identify as a significant deficiency, however the State may choose
to use their authority to require source water monitoring to monitor
the influence of that fecal source. Ground water systems which provide
4-log inactivation or removal of viruses will be required to conduct
compliance monitoring to demonstrate treatment effectiveness. States
must confirm that the deficiency has been corrected, either through
written confirmation from systems or a site visit by the State, within
30 days after the 90-day or scheduled correction of the deficiency.
Systems providing 4-log inactivation or removal of viruses need not
undergo a hydrogeologic sensitivity assessment or monitor their source
water for fecal indicators.
As noted earlier, States would be required to have the appropriate
rules or other authority to: (1) Ensure that public ground water
systems correct any significant deficiencies identified in the written
notification provided by the State (including providing an alternative
source or 4-log inactivation or removal of viruses); and (2) ensure
that a public ground water system confirm in writing any significant
deficiency corrections made as a result of sanitary survey findings.
The requirements in today's rule do not preclude a State from
enforcing corrective action on any significant deficiencies whether or
not they are identified through a sanitary survey.
EPA is also proposing to require States, as part of their primacy
application, to indicate how they will
[[Page 30221]]
define what constitutes a significant deficiency found in a sanitary
survey for purposes of this rule. EPA believes that this requirement
would provide the State sufficient latitude to work within their
existing programs in addressing significant deficiencies yet provide
facilities and the public with clear notice as to what kinds of system
conditions constitute a significant deficiency. EPA recognizes the
importance of enabling States the flexibility to identify and define
sanitary survey deficiencies in broad categories under this requirement
(e.g., unsafe source, improper well construction, etc.).
Also, in its primacy application, States must specify if and how
they will integrate SWAPP susceptibility determinations into the
sanitary survey or the definition of significant deficiencies.
Based upon input from a number of State and EPA Regional office
experts, significant deficiencies of ground water systems may include
but are not limited, to the following types of deficiencies:
--Unsafe source (e.g., septic systems, sewer lines, feed lots nearby);
--Wells of improper construction;
--Presence of fecal indicators in raw water samples;
--Lack of proper cross connection control for treatment chemicals;
--Lack of redundant mechanical components where chlorination is
required for disinfection;
--Improper venting of storage tank;
--Lack of proper screening of overflow pipe and drain;
--Inadequate roofing (e.g., holes in the storage tank, improper hatch
construction);
--Inadequate internal cleaning and maintenance of storage tank;
--Unprotected cross connection (e.g., hose bibs without vacuum
breakers);
--Unacceptable system leakage that could result in entrance of
contaminants;
--Inadequate monitoring of disinfectant residual and TCR MCL or
monitoring violations.
6. Reporting and Record Keeping Requirements
The GWR does not change the requirements on the system and the
State to maintain reports and records of sanitary survey information as
specified in 40 CFR 141.33(c) and 142.14(d)(1).
7. Request for Comments
EPA requests comment on all the information presented earlier and
the potential impacts on public health and regulatory provisions of the
GWR. In addition, EPA specifically requests comments on alternative
approaches.
Alternative Approaches
a. Content of a Sanitary Survey
i. Grandfathering and Scope of Sanitary Survey
EPA requests comment on ``grandfathering'' of surveys conducted
under the TCR if those surveys addressed all eight EPA/State Joint
Guidance on Sanitary Surveys components. Under what circumstances
should grandfathering be allowed? Are there circumstances under which
grandfathering should be allowed even if the survey did not address all
eight components?
EPA is seeking comment on the level of detail EPA should use in
establishing the sanitary survey requirement which addresses the eight
sanitary survey components.
ii. Definition of Significant Deficiency
EPA is also seeking comment on the proposed definition of
``significant deficiencies.'' In this regard, EPA is requesting comment
on whether or not the Agency should promulgate a minimum list of
specific significant deficiencies for all States to use in their
programs.
iii. Well Construction and Age
EPA considered specifying, in addition to sanitary survey elements,
well construction deficiencies and well age as surrogate measures of
well performance as part of the hydrogeologic sensitivity assessment
(HSA) or as an independent component from the sanitary survey or HSA.
EPA considered identifying older wells as those more likely to be
contaminated because of degradation to the construction materials over
time. EPA concluded that wells may have been constructed adequately to
protect public health, but records to document such construction may no
longer be available. Given these circumstances, EPA recognizes that
down-hole test methods to evaluate well construction, as required for
some hazardous waste disposal methods, is neither desirable nor
feasible for PWS wells. In addition, EPA found that there were few data
to support the concept that older wells were more likely to be
contaminated. In fact, data from two studies encompassing more than 200
wells in Missouri suggest that newer wells were more likely to be
contaminated than older wells (Davis and Witt, 1998, 1999 and Femmer,
1999). Thus, EPA decided not to include well construction and age as
measures of the potential fecal hazard to PWS wells.
Almost all States have well construction standards, and trade
associations, such as the American Water Works Association and the
National Ground Water Association, have also provided recommendations
for well construction. EPA recognizes the importance of designing,
constructing and maintaining wells so as to maximize well life and
yield and to minimize potential harmful contamination. Therefore, the
Agency requests comment on whether well construction and age should be
considered as a required element within a sanitary survey or
specifically identified by States as a significant deficiency. EPA also
requests comment on criteria for evaluating well construction and age.
b. Frequency
EPA believes that a sanitary survey cycle of at least once every
three years for CWSs (with certain exceptions discussed previously) and
at least once every five years for NCWSs most properly balances public
health protection and State burden issues and is consistent with the
frequency required for surface water systems. However, the Agency seeks
comment on whether other alternative time cycles might be appropriate
together with any applicable rationale that supports that alternative
frequency cycle. Specifically, EPA requests comment on requiring States
to conduct sanitary surveys for all ground water systems every five
years. EPA also requests comment on allowing States to conduct sanitary
surveys less often than once every 5 years if the system provides 4-log
inactivation or removal. The Agency requests comment on the resource
implications for States and small systems to perform these surveys with
a frequency of 3-5 years.
In addition, the Agency seeks comment on requiring the State to
conduct a sanitary survey for new systems prior to the system serving
water to the public. This requirement would serve as an added public
health measure to ensure new systems are in compliance with the GWR
sanitary survey provisions.
c. Follow-Up Requirements
EPA requests comment on requiring States to schedule an on-site
inspection as follow-up to verify correction of significant
deficiencies, rather than allowing States to accept written
certification from systems to verify the correction. EPA requests
comment on alternative approaches for a State to verify that a
significant deficiency has
[[Page 30222]]
been corrected. EPA notes that follow-up in this context only applies
to significant deficiencies.
d. Public Involvement
EPA requests comment on including public involvement and/or
meetings for certain systems to discuss the results of sanitary
surveys. Congress wrote requirements for extensive public information
and involvement in programs and decisions affecting drinking water
safety throughout the 1996 amendments to SDWA. For example, in addition
to the new requirement for CWSs to produce and distribute annually a
Consumer Confidence Report, the public notice requirements for PWSs
regarding violations of a national drinking water standard were made
more effective, and States were required to ``make readily available to
the public'' an annual report to the Administrator on the statewide
record of PWS violations, see (SDWA 1414(c)(1)-(3)). Each State's
triennial report to the Governor on the effectiveness of and progress
under the capacity development strategy must also be available to the
public. (See SDWA section 1420(c)(3)). EPA must make the information
from the occurrence database ``available to the public in readily
accessible form.'' (See SDWA section 1445(g)(5)). The public must be
provided with notice and an opportunity to comment on the annual
priority list of projects eligible for State Revolving Fund (SRF)
assistance that States will publish as a part of their SRF intended use
plans (See SDWA section 1452(b)(3)(B)). States ``shall make the results
of the source water assessments * * * available to the public.'' (See
SDWA section 1453(a)(7)). And, under several specific provisions of the
SDWA as well as the Administrative Procedure Act, EPA generally must
publish and make regulations, and a number of guidance and information
documents, available for public notice and comment.
These requirements, and others like them, are integral to both the
philosophy and operation of the amended SDWA. They reflect Congress'
view that public confidence in drinking water safety and informed
support for any needed improvements must rest on full disclosure of all
significant information about water system conditions and quality, from
source to tap.
The 1996 SDWA Amendments, and EPA's implementation of them,
consistently provide for such disclosure and involvement by means that
are informative, timely, understandable, and practicable for each size
group of PWSs subject to them. EPA believes that the principles of
public information and involvement must apply with equal validity to
the GWR, and is considering including in the final rule provisions to
apply these principles, for disclosure and involvement. EPA believes
that the following approach meets both tests and principles, but
solicits comment on alternative means of doing so.
EPA requests comment on what approaches might be practicable, not
burdensome and workable to involve the public in working with their
system to address the results of their system's sanitary survey.
Specifically, EPA requests comment on requiring ground water CWSs to
notify their consumers, as part of the next billing cycle, of the
completion of any sanitary survey, and any significant deficiency(s)
and corrective action(s) identified. The system would also have to make
information concerning the sanitary survey available to the public upon
request. Alternatively, the system might be required to notify
customers of the availability of the survey only, and provide copies on
request, or include information about the survey in the annual Consumer
Confidence Report (CCR). EPA requests comment on whether this approach
should be extended to transient and nontransient NCWSs as well. EPA
also requests comment on what approaches might be practicable, not
burdensome and workable to involve the public in working with their
system to address the results of their system's sanitary survey.
B. Hydrogeologic Sensitivity Assessment
1. Overview and Purpose
Occurrence data collected at the source from public ground water
systems suggest that a small percentage of all ground water systems are
fecally contaminated. Because of the large number of ground water
systems (156,000), the GWR carefully targets the high priority systems
and has minimal regulatory burden for the remaining low priority
systems. The GWR screens all systems for priority and only requires
corrective action for fecally contaminated systems and systems with
significant deficiencies. Thus, the challenge of the hydrogeologic
sensitivity assessment is to identify ground water wells sensitive to
fecal contamination. The assessment supplements the sanitary survey by
evaluating the risk factors associated with the hydrogeologic setting
of the system. EPA believes requiring hydrogeologic sensitivity
analysis for all non-disinfecting ground water systems will reduce risk
of waterborne disease by identifying systems with incomplete natural
attenuation of fecal contamination. EPA bases the following
requirements on: CDC outbreak case studies, USGS studies of ground
water flow, State vulnerability maps, and US National Research Council
reports on predicting ground water vulnerability.
For the purposes of this rulemaking, EPA intends the term ``well''
to include any method or device that conveys ground water to the ground
water system. The term ``well'' include springs, springboxes, vertical
and horizontal wells and infiltration galleries so long as they meet
the general applicability of the GWR (see section 141.400). The GWR
does not apply to PWSs that are designated ground water under the
direct influence of surface water; such systems are subject to the SWTR
and IESWTR. EPA requests comment on this definition of ``well.''
The hydrogeologic sensitivity assessment is a simple, low burden,
cost-effective approach that will allow States to screen for high
priority systems. Systems that are situated in certain hydrogeologic
settings are more likely to become contaminated. EPA believes that a
well obtaining water from a karst, fractured bedrock or gravel
hydrogeologic setting is sensitive to fecal contamination unless the
well is protected by a hydrogeologic barrier. A State may add
additional sensitive hydrogeologic settings (e.g., volcanic aquifers)
if it believes that it is necessary to do so to protect public health.
A hydrogeologic barrier is defined as the physical, biological and
chemical factors, singularly or in combination, that prevent the
movement of viable pathogens from a contaminant source to a public
supply well. In this proposal, a confining layer is one example of a
hydrogeologic barrier. The strategy is for a State to consider
hydrogeologic sensitivity first. If ground water systems not treating
to 4-log inactivation of viruses are located in sensitive hydrogeologic
settings, then the strategy allows the State to consider the presence
of any existing hydrogeologic barriers that act to protect public
health. If a hydrogeologic barrier is present, then the State can
nullify the determination that a system is located in a sensitive
hydrogeologic setting. If no suitable hydrogeologic barrier exists,
then the GWR requires the system to conduct monthly fecal indicator
source water monitoring. Finally, for those systems where monitoring
results are positive for the presence of fecal indicators, under the
proposed GWR, States may require systems to eliminate
[[Page 30223]]
the source of contamination, correct the significant deficiency,
provide an alternate source water, or provide a treatment which
reliably achieves at least 99.99 percent (4-log) inactivation or
removal of viruses before or at the first customer. GWSs which provide
4-log inactivation or removal of viruses will be required to conduct
compliance monitoring to demonstrate treatment effectiveness.
The States have experience implementing a wide variety of methods
suitable for identifying hydrogeologically sensitive systems. Also, the
States may collect hydrogeologic information through their SWAPP (see
section I.B.) that is useful for the hydrogeologic sensitivity
assessments under the GWR. EPA believes that it would be beneficial if
the States coordinate their SWAPP analysis with the GWR. By using the
information generated in the SWAPP for the GWR hydrogeologic
sensitivity assessment, States can effectively reduce the burden
associated with this requirement.
EPA-approved vulnerability assessments conducted for the purpose of
granting waivers under the Phase II and Phase V Rules may also serve as
sources of hydrogeologic information useful to the State in assessing
the hydrogeologic sensitivity of its GWSs under the GWR. Under the
Phase II (56 FR 30268, July 1, 1991d)(US EPA,1991) and Phase V (57 FR
31821, July 17, 1992)(US EPA,1992b) Rules, monitoring waivers may be
granted to individual systems for specific regulated chemicals (e.g.,
PCBs and cyanide). Monitoring frequencies may be reduced or eliminated
by the State if the system obtains a waiver based on previous sampling
results and/or an assessment of the system's vulnerability to each
Phase II and V contaminant. This evaluation must include the sampling
results of neighboring systems, the environmental persistence and
transport of the contaminant(s) under review, how well the source is
protected by geology and well design, Wellhead Protection Assessments,
and proximity of potential contamination sites and activities.
2. Hydrogeologic Sensitivity
Sensitive hydrogeologic settings occur in aquifer types that are
characterized by large interconnected openings (void space) and,
therefore, may transmit ground water at rapid velocities with virtually
no removal of pathogens. Sensitive aquifers may be present at or near
the ground surface or they may be covered by overlying aquifers or
soils. An aquifer is sensitive, independent of its depth or the nature
of the overlying material, because average water velocities within that
aquifer are rapid. This allows microbial contaminants to be transported
long distances from their source at or near the surface and especially
in the absence of a hydrogeologic barrier. In the following paragraphs,
each sensitive aquifer type is briefly characterized. It is often
difficult to determine the actual contaminant removal capabilities of
an aquifer and the and ground water velocities within an aquifer.
Consequently, the aquifer rock type can be a surrogate measure in the
hydrogeologic sensitivity assessment. All soil and rocks have void
space, but aquifers have the largest interconnected void space. The
voids are filled with water that is tapped by a well. Without these
interconnections, the water could not flow to a well. In those aquifers
with the largest interconnected void space, ground water velocities can
be comparable to the velocity of a river, and the rate of travel can be
measured in kilometers per day (US EPA, 1997b). Compared to velocities
in fine-grained granular aquifers (aquifers that are not considered
sensitive under the GWR), ground water velocities in fractured media
are large (Freeze and Cherry, 1979). Sensitive aquifers allow fecal
contaminants to travel rapidly to a well, with little loss in number
due to inactivation or removal.
In the GWR, three aquifer types are identified as sensitive: (1)
Karst aquifers, (2) fractured bedrock aquifers, and (3) gravel
aquifers. Each aquifer type is characterized by the differing nature
and origin of the interconnected void space. These distinctions are
important to hydrogeologists identifying these aquifer types. To meet
the requirements of the hydrogeologic sensitivity assessment of the
GWR, it is sufficient for States to identify the aquifer type supplying
a system. Karst, fractured bedrock and gravel aquifer types are at high
risk to fecal contamination by virtue of their capability to rapidly
transmit fecal contamination long distances over short time periods.
Several means can be used to evaluate wells to determine if they
are located in one of the three sensitive hydrogeologic settings
proposed under the GWR. For example, hydrogeologic data are available
from published and unpublished materials such as maps, reports, and
well logs. The United States Geologic Service (USGS), U.S. Department
of Agriculture's Natural Resource Conservation Service, USGS Earth
Resources Observation System Data Center, the EPA Source Water
Assessment and Protection Program and Wellhead Protection Program,
State geological surveys, and universities have substantial amounts of
regional and site-specific information. The USGS has published a
national karst map (USGS, 1984) on which States can locate karst
settings. Karst and other aquifers may also be identified on finer
scale maps published by States or counties. For example, the State of
Kentucky contains substantial karst terrain, documented in complete
geologic maps at the scale of one inch: 2000 feet (7.5 minute
quadrangles).
States can base assessments on available information about the age
and character of the regional geology, regional maps and rock outcrop
locations. For example, in a karst setting, the State may have some
additional information such as: (1) Observations of typical karst
features such as sinkholes and disappearing streams; (2) well driller
logs which noted the presence of limestone or crystalline calcite (a
mineral that grows into openings in rock) or a drop in the drill string
as it penetrated a karst opening; or (3) geologic reports (or
unpublished geological observations) which identify the presence of
limestone in rock outcrops in the vicinity of the well.
(a) Karst Aquifers
Karst aquifers are aquifers formed in soluble materials (limestone,
dolomite, marble and bedded gypsum) that have openings at least as
large as a few millimeters in radius (EPA 1997b). Over geologic time
periods, infiltrating precipitation (especially acid rain) moving
through the aquifer has enlarged, by dissolution, the small openings
that existed when the rock was formed. In mature karst terrain,
characterized by relatively pure limestone located in regions with high
precipitation, caves or caverns are formed in the subsurface, often
large enough for human passage. Ground water has the potential to flow
rapidly through karst because the void spaces are large and have a high
degree of interconnection. In addition to the openings created by
solution removal, karst aquifers, like all consolidated geologic
formations, also contain fractures that transmit ground water. The size
of these fractures may be small, but the fractures may also be more
numerous than solution-enhanced openings. The fractures may or may not
have a high degree of interconnection, and the degree of
interconnection is a primary factor that controls the velocity of the
ground water.
[[Page 30224]]
Quinlan (1989) suggests that about 20 percent of the U.S. is
underlain by limestone or dolomite which may be karst aquifers. East of
the Mississippi River, almost forty percent of the U.S. is underlain by
limestone, dolomite or marble that may be karst aquifers (Quinlan,
1989). Karst areas are often identified by the formation of sinkholes
at the ground surface. A sinkhole forms when the roof of a cave
collapses and the material that was overlying the cave is dissolved or
otherwise carried away by streams flowing through the cave. Sinkholes
may also form or become enlarged as the direct result of vertical
ground water flow dissolving the rock material to form a vertical
passageway. Sinkholes represent direct pathways for fecal contamination
to enter the aquifer from the surface. The surface topography may also
be characterized by dry stream valleys in regions of high rainfall, by
streams that flow on the ground surface but suddenly sink below ground
to flow within a cave and by large springs where underground streams
return to the surface. The degree of karst development in Missouri has
been defined by Davis and Witt (1998) as primary and secondary karst:
primary containing more than ten sinkholes per 100 square miles and
secondary karst containing between one and ten sinkholes per 100 square
miles. Other features suitable for identifying karst aquifers are
described in EPA (1997b).
The most direct method for ground water velocity determinations
consists of introducing a tracer substance at one point in the ground
water flow path and observing its arrival at other points in the path,
usually at monitoring wells (Freeze and Cherry, 1979). Using tracer
studies, ground water velocities in karst aquifers have been measured
as high as 0.5 kilometers (km) per hour (US EPA, 1997b). In Florida,
ground water velocities surrounding a well have been measured at
several hundred meters (m) per hour (US EPA, 1997b). At Mammoth Cave,
Kentucky, ground water velocities have been measured at more than 300 m
per hour (US EPA, 1997b). In a confined karst aquifer in Germany,
ground water traveled 200 m in less than 4 days (Orth et al., 1997). In
the Edwards Aquifer, Texas, Slade et al., (1986) reported that dye
traveled 200 feet in ten minutes. The water level in one well (582 feet
deep with a water table 240 feet deep) began rising within one hour
after a rainfall (Slade et al., 1986). These data suggest that ground
water flows extremely rapidly through karst aquifers. Because ground
water flows rapidly through karst aquifers, these aquifers are
considered to be hydrogeologically sensitive aquifers under the GWR.
(b) Fractured Bedrock
Bouchier (1998) characterizes a fractured bedrock aquifer as an
aquifer which has fractures that provide the dominant flow-path.
Although all rock types have fractures, the rock types most susceptible
to fracturing are igneous and metamorphic rock types (US EPA, 1991c).
Freeze and Cherry (1979) report void space as high as 10 percent of
total volume in igneous and metamorphic rock. These rock types readily
become fractured in the shallow subsurface as a result of shifts in the
Earth's crust. Most fractures are smaller than one millimeter (mm) in
width but each fracture's capability to transmit ground water varies
significantly with the width of the fracture. A one mm fracture will
transmit 1,000 times more water than a 0.1 mm fracture, provided that
other factors are constant (e.g., hydraulic gradient) (Freeze and
Cherry, 1979). Data presented in Freeze and Cherry (1979) suggest that
the first 200 feet beneath the ground surface produces the highest
water yields to wells. These data suggest that the fractures are both
more numerous and more interconnected in the first 200 feet interval.
The rate of ground water travel in fractured rock can be estimated
through the results of tracer tests. Malard et al., (1994) report that
dye traveled 43 m in a fractured aquifer in two hours. Becker et. al.,
(1998) report that water traveled 36 m in about 30 minutes. Therefore,
ground water may travel as quickly as several hundreds of meters per
day in fractured bedrock, comparable to travel times in karst aquifers.
Aquifers that are comprised of igneous or metamorphic rock are
often fractured bedrock aquifers, and their size is typically larger
than a few tens or hundreds of square miles in area. EPA (1991c) has
compiled a map showing the distribution of fractured bedrock aquifers
in the U.S. Because ground water flows rapidly through fractured
bedrock aquifers, these aquifers are considered to be hydrogeologically
sensitive aquifers under the GWR.
(c) Gravel Hydrogeology
Gravel aquifers are deposits of unconsolidated gravel, cobbles and
boulders (material larger in size than pebbles). Due to the large grain
sizes of gravel aquifers, ground water travels rapidly within these
aquifers with little to no removal or filtration of contaminants from
the ground water. Such gravel aquifers are typically produced by
catastrophic floods, physical weathering by glaciers, flash-floods at
the periphery of mountainous terrain or at fault-basin boundaries. For
example, glacial flooding has produced the Spokane-Rathdrum Prairie
aquifer which extends from Spokane, Washington to Coeur d'Alene, Idaho.
Another gravel aquifer is associated with glacial flooding along the
Umatilla River in Milton-Freewater, Oregon. The boulder zone in the
Jacobs Sandstone and Baraboo Quartzite near Baraboo, Wisconsin may
represent another example. Typically, these aquifers are small.
Gravel aquifers are generally not alluvial aquifers. Alluvial
aquifers, associated with typical river processes, normally have high
proportions of sand mixed with the gravel. Sand or finer materials
provide a higher probability of microorganism removal by the aquifer
particles (Freeze and Cherry, 1979), and, therefore, greater public
health protection. Because ground water flows rapidly through gravel
aquifers, these aquifers are considered to be hydrogeologically
sensitive aquifers under the GWR.
3. Hydrogeologic Barrier
The second part of the hydrogeologic sensitivity assessment is
determining the presence of a hydrogeologic barrier. Under the GWR, the
States perform an initial screen for hydrogeologic sensitivity by
determining whether a PWS utilizes a fractured bedrock, karst or gravel
aquifer. States would then examine systems located in these sensitive
aquifers and determine whether a hydrogeologic barrier is present. A
hydrogeologic barrier consists of physical, chemical, and biological
factors that, singularly or in combination, prevent the movement of
viable pathogens from a contaminant source to a public water supply
well. If the State determines that a hydrogeologic barrier is present,
the hydrogeologic setting is no longer considered sensitive to fecal
contamination. If no such barrier is present or if insufficient
information is available to make such a determination, the system would
be identified as a sensitive system.
It is difficult to describe a single, detailed methodology for
identifying a hydrogeologic barrier that can be used on a national
basis. Geological and geochemical conditions, climate, and land uses
are highly variable throughout the United States. In its primacy
application, each State seeking consideration of a proposed
hydrogeologic barrier under the rule may identify an approach for
[[Page 30225]]
determining the presence of a hydrogeologic barrier that addresses its
own unique set of these variables (e.g., geological and geochemical
conditions, climate, and land uses). In determining the presence of a
hydrogeologic barrier, the State should evaluate specific
characteristics of the hydrogeologic setting, discussed in more detail
in the following paragraphs.
Examples of characteristics to be considered in determining the
presence of a hydrogeologic barrier include, but are not limited to:
(1) Subsurface vertical and horizontal ground water travel times or
distances sufficiently large so that pathogens become inactivated as
they travel from a source to a public water supply well, or (2)
unsaturated geological materials sufficiently thick so that
infiltrating precipitation mixed with fecal contaminants is effectively
filtered during downward flow to the water table.
A confining layer is one type of hydrogeologic barrier EPA has
identified which can result in sufficient protection in many settings.
A confining layer may protect sensitive aquifers from fecal
contamination. It is defined as a layer of material that is not very
permeable to ground water flow which overlies an aquifer and acts to
prevent water movement into the aquifer (US EPA, 1991b). Confined
aquifers are bounded by confining layers and, therefore, generally
occur at depth, separated from the water table aquifer at the surface.
Confining layers are typically identified by the high water pressures
in the underlying aquifer. Where present, a confining layer will
separate an aquifer of high pressure from an overlying aquifer of lower
pressure. The high water pressure in a confined aquifer can force water
to flow naturally (without pumping) to heights greater than the ground
surface, as in an artesian well. The confining layer is comprised of
fine-grained materials such as clay particles, either as an
unconsolidated layer or as a consolidated rock (e.g., shale). The small
size of clay particles restricts the movement of water across or
through the clay layer. Freeze and Cherry (1979) determined that water
would take almost 10,000 years to pass through a 10 meters-thick
unfractured layer of silt and clay deposited at the bottom of a glacial
lake, such as the layers present in the northern part of the United
States and the southern part of Canada. Therefore, the presence of a
confining layer can provide public health protection.
However, confining layers may be breached and, therefore,
unprotective. Breaches may be natural (e.g., partly removed by erosion,
sinkholes, faults, and fractures) or caused by humans (e.g., wells,
mines, and boreholes). For example, an unplugged, abandoned well that
breaches the confining layer is capable of providing a pathway through
the confining layer, allowing water and contaminant infiltration into
ground water. A thicker, unpunctured confining layer is considered most
protective of the underlying aquifer. The State should consider such
confined aquifer characteristics in determining the adequacy of a
confining layer as a hydrogeologic barrier.
EPA proposes to use the presence of a confining layer that is
protective of the aquifer to act as a hydrogeologic barrier and nullify
a sensitivity determination. Where the confining layer integrity is
compromised by breaches or if the aquifer appears at the surface near
the water supply well, the State shall determine if the layer is
performing adequately to protect the well, and, therefore, public
health. EPA estimates approximately 15 percent of undisinfected ground
water system sources will be determined to be hydrogeologically
sensitive (see RIA section 6.2.1.1).
4. Alternative Approaches to Hydrogeologic Sensitivity Assessment
EPA recognizes that the States have substantial experience
characterizing hydrogeology. Most States require some hydrogeologic
information for reasons such as to delineate wellhead protection areas,
manage ground water extraction or assess ground water contamination.
EPA recognizes that there is no single approach for identifying systems
at risk from source water contamination. In the GWR, a selected subset
of hydrogeologic settings (karst, fractured bedrock and gravel
aquifers) is hydrogeologically sensitive. These hydrogeologic settings
are identified through regional and local maps that show the general
distribution of these settings. Other approaches considered by EPA to
identify sensitive systems, but not selected, require additional data
that may not be available to all States. In the following paragraphs,
alternative methods to identify sensitive systems are discussed,
including the data requirements for implementing each approach.
(a) Horizontal Ground Water Travel Time
Horizontal ground water travel time is the time that a water volume
requires to travel through an aquifer from a fecal contamination source
to a well. Viruses are longer lived than bacteria. Therefore, the
ground water travel time should allow sufficient virus die-off to take
place such that the concentration of viruses in the well water would be
at or below a 1 in 10,000 annual risk level (Regli et. al., 1991).
However, travel time determinations are site specific, and some methods
are expensive and/or difficult to perform. Therefore, EPA is not
prescribing a particular travel time as a hydrogeologic sensitivity
assessment criterion under the GWR. Travel time information may be
useful for evaluating hydrogeologic barrier performance, and States may
make use of this information where available.
Ground water travel time measurement methods include conservative
tracer tests (e.g., dyes, stable isotopes), and travel time
calculations. Conservative tracer tests may be used in all aquifer
types including karst and fractured bedrock, as well as porous media
aquifers. Tracer tests are expensive and difficult to perform. Ground
water travel time calculations are only suitable for porous media
aquifers. Because travel time methods are site-specific and their
associated levels of uncertainty vary, EPA is not prescribing one
travel time number or method to be used nationally.
In evaluating whether to require a specific ground water travel
time, EPA recognized that there are three problems with requiring this
method for all States. First, all ground water travel time calculations
require measurement of the aquifer porosity (void space). Aquifer
porosity data are rare and usually must be estimated based on the
aquifer character (e.g., sand, or sand and gravel). Second, ground
water travel time calculations require knowledge of the distance
traveled and water velocity; however, calculating travel time is
complicated because ground water does not travel in a straight line.
The ground water's flow path can be nearly straight, as in the case of
cavernous karst or it can be very convoluted as found in fractured
media. Third, the ground water travel time value represents the average
travel time of a large water volume moving toward a well. Some water
arrives more quickly than the average. Because viruses and bacteria are
small in size their charge effects become important. As a result, some
fecal contaminants may take the fastest path from source to well and
arrive faster than the average water volume. Fecal contaminants
introduced into an aquifer may or may not be channeled into flow paths
that move faster than the average water volume. Thus, a calculation of
the average ground water travel time is not as protective as the
calculation of the first arrival time of the
[[Page 30226]]
ground water volume. Because of the additional uncertainty in
calculating first arrival times, average travel times must be augmented
with a safety factor. Travel time data, where available, may assist
States in evaluating hydrogeologic barriers for localities where all
sources of fecal contamination have been identified.
(b) Setback Distance
A setback distance is the distance between a well and a potential
contamination source. Many States already use setback distances around
a well as exclusion zones in which septic tanks are prohibited.
EPA compiled data on State sanitary setback distances for PWS
wells. EPA found that there is little uniformity among the States.
State setback distances from septic tanks or drain fields for new PWS
wells range from 50 to 500 feet. Moreover, some States have differing
setback distances depending on the well type (e.g., CWS versus NTNCWS
and TNCWS ), the well pumping rate (e.g., greater or less than 50
gallons per minute) or the microbial contaminant source type (e.g., 50
feet from a septic tank and 10 feet from a sewer line).
EPA considered using a strategy that included the setback distance
as an element in determining the potential fecal hazard to systems. In
this strategy, wells located near contamination sources are at risk.
EPA concluded that it would be difficult to implement this strategy on
a national scale for two reasons. First, the differing State setback
distance requirements suggests that there is substantial disagreement
among the States about an appropriate setback distance. Second, any
setback distance selected for use in the GWR must be sufficiently large
so as to protect a well from fecal contamination. The complexity of the
processes that govern virus and bacterial transport in ground water and
the variability of ground water velocity in sensitive hydrogeologic
settings make it difficult, if not impossible, for EPA to specify
setback distances that will be protective of public health for all
hydrogeologic settings. Thus, EPA concluded that there was insufficient
scientific data to mandate national setback distances in the GWR.
(c) Well and Water Table Depth
Well depth is the vertical distance between the ground surface and
the well intake interval or the bottom of the well. Water table depth
is the vertical distance between the ground surface and the water
table. Infiltrating ground water can require substantial time to reach
a deep well or a deep water table because precipitation infiltrating
downward to the water table and vertical ground water flow within an
aquifer are typically slow, and thus the long infiltration path to a
deep well or water table provides opportunities for inactivation or
removal of pathogens and is protective against source water
contamination.
EPA considered identifying well depth and water table depth as
alternative hydrogeologic sensitivity methods. Two key pieces of
information would then be needed for each well: (1) Aquifer
measurements that describe its capability to vertically transmit ground
water and (2) measurements from the soil and other material overlying
the water table that describe its capability to transmit infiltrating
precipitation mixed with fecal contamination. EPA believes that few
data are available to describe vertical ground water flow or
infiltration on a national level. Thus, EPA concluded that there was
insufficient data available to determine a well depth at which there
exists a fecal contamination risk for all systems on a national scale.
5. Proposed Requirements
(a) Assessment Criteria
Today's proposal provides that States shall identify high priority
systems through a hydrogeologic sensitivity assessment. In this
assessment, wells located in karst, fractured bedrock or gravel
hydrogeologic settings are determined to be sensitive. The information
provided in previous paragraphs shows that the wells located in these
hydrogeologic settings are potentially at risk of fecal contamination
because ground water velocities are high and fecal contamination can
travel long distances over a short time. A hydrogeologic barrier can
protect a sensitive aquifer, and if present, can nullify the
sensitivity determination. In its primacy application, a State shall
identify its approach to determine the presence of a hydrogeologic
barrier. For example, a State may choose to consider a specific depth,
hydraulic conductivity, and the presence of improperly abandoned wells.
For systems with one or more wells that potentially produce ground
water from multiple aquifers, the State shall identify its approach to
making separate hydrogeologic sensitivity determinations and, if
appropriate, hydrogeologic barriers identifications, for each well. For
example, a State may choose to consider a specific depth and hydraulic
conductivity, improperly abandoned wells. The system shall provide to
the State or EPA, at its request, any pertinent existing information
that would allow the State to perform a hydrogeologic sensitivity
analysis. The hydrogeologic sensitivity assessment does not necessarily
require an on-site visit by the State, provided the State has adequate
information (geologic surveys, etc.) to make the assessment without a
site visit.
Discussions of proposed monitoring requirements for
hydrogeologically sensitive systems are found in section III.D., and
corrective action requirements are found in section III.E.
(b) Frequency of Assessment
The States, or their authorized agent, shall conduct one
hydrogeologic sensitivity assessments for each GWS that does not
provide treatment to 4-log inactivation or removal of viruses. States
shall conduct the hydrogeologic sensitivity assessment for all existing
CWSs no later than three years after publication of the final rule in
the Federal Register and for all existing NCWSs no later than five
years after publication of the final rule in the Federal Register.
States shall complete the hydrogeologic sensitivity assessment prior to
a new ground water system providing drinking water for public
consumption. EPA requests comment on these time frames. Some
stakeholders have indicated that an assessment for hydrogeologically
sensitive areas (karst, gravel, fractured rock) of a State can be
quickly performed at the State level. If such data can be quickly
gathered and an assessment easily performed, EPA questions putting off
the routine monitoring requirements and public health protection that
it would bring for three or five years. EPA requests comment on
requiring the State to perform the hydrogeologic sensitivity assessment
within one year of the effective date of the final GWR.
(c) Reporting and Record Keeping Requirements
The State shall keep records of the supporting information and
explanation of the technical basis for determinations of hydrogeologic
sensitivity and of the presence of hydrogeologic barriers. The State
shall keep a list of ground water systems which have had a sensitivity
assessment completed during the previous year, a list of those systems
which are sensitive, a list of those systems that are sensitive, but
for which the State has determined a hydrogeologic barrier exists at
the site sufficient for protecting public health, and a record of an
annual evaluation of the State's program for conducting hydrogeologic
sensitivity assessments.
[[Page 30227]]
6. Request for Comments
EPA requests comments on all the information presented earlier and
the potential impacts on public health and the regulatory provisions of
the GWR.
a. Routine Monitoring Without State Assessment
EPA requests comment on requiring systems to perform routine
monitoring if the State fails to conduct a hydrogeologic sensitivity
assessment. Under this provision, if the State fails to conduct a
hydrogeologic sensitivity assessment within the time frame specified by
the GWR, the systems would conduct fecal indicator monitoring once per
month for every month they serve water to the public (see section
Sec. 141.403(d), microbial analytical methods). The time frame for
completing sensitivity assessments for all existing CWSs is no later
than three years after the date of publication of the final rule in the
Federal Register, and the time frame for all existing NCWSs is no later
than five years after the date of publication of the final rule in the
Federal Register. The systems could discontinue monitoring only after
the State conducts a hydrogeologic sensitivity assessment and
determines that the systems are not sensitive, or if the systems
initiate and continue treatment to achieve 4-log inactivation or
removal of viruses.
b. Vulnerability Assessment
EPA requests comment on a detailed, on-site vulnerability
investigation as an alternative to the Hydrogeologic Sensitivity
Assessment. The alternative hydrogeologic investigation will assess the
performance of all existing hydrogeologic barriers such as unsaturated
zone thickness and composition (including the soil), the saturated zone
thickness and composition above the well, intake interval, the
frequency, duration and intensity of precipitation for all aquifer
types, and will also require a detailed investigation of the well
construction conditions by a certified well technician and a review of
the well construction-related documentation from the sanitary survey
and SWAPP assessment. The results of the detailed investigation must
demonstrate that the existing hydrogeologic barriers, aquifer type and
the well construction function to prevent the movement of viable
pathogens from a contaminant source to a public water supply well. The
demonstration may include ground water age dating, natural or
artificial tracer test data, or ground water modeling results. See EPA
1998b for more information on vulnerability assessments.
c. Sandy Aquifers
EPA is proposing to require States to identify systems in karst,
gravel and fractured rock aquifer settings as sensitive and these
systems must perform routine source water monitoring. On March 13,
2000, the Drinking Water Committee of the Science Advisory Board
(DWCSAB) reviewed this issue and made several recommendations to EPA
concerning a draft of this proposal. EPA requests comment on two DWCSAB
recommendations concerning the hydrogeologic sensitivity assessment.
The committee recommended that all ground water sources be required to
monitor for bacterial indicators and coliphage for at least one year--
regardless of sensitivity determination. As an alternative approach,
the committee recommended sand aquifers be included as sensitive
settings. This recommendations was based on column studies of virus
transport in soils that showed that viruses move rapidly through sandy
soils and field studies of virus transport from septic tanks showing
rapid movement into ground water from sandy coastal plains.
C. Cross Connection Control
EPA is concerned about introduction of fecal contamination through
distribution systems; however, EPA has not proposed cross connection
control requirements in the GWR. EPA will work with the Microbial/DBP
FACA to consider whether cross connection control should be required in
future microbial regulations, particularly during the development of
the Long Term 2 ESWTR, in the context of a broad range of issues
related to distribution systems. EPA will also request input from the
FACA on whether to require systems to maintain disinfection residual
throughout the distribution system. EPA seeks comments or additional
supporting data related to cross connection control or other
distribution system issues. In particular to cross connections, the
Agency requests public comment on: (1) Whether EPA should require
States and/or systems to have a cross connection control program, (2)
what specific criteria, if any, should be included in such a
requirement, (3) how often a program should be evaluated, (4) and
whether EPA should limit any requirement to only those connections
identified as a cross connection by the public water system or the
State. The Agency also requests comment on what other regulatory
measures EPA should consider to prevent contamination of drinking water
in the distribution system.
D. Source Water Monitoring
1. Overview and Purpose
As previously stated, EPA recognizes that there are particular
challenges associated with developing an effective regulatory approach
for ground water systems. These include the large number of ground
water systems that would be regulated, the fact that only a subset of
these systems appear to have fecal contamination (although a larger
number are likely to be sensitive), and that most ground water systems
range from small to very small in terms of the population served. These
factors combine to underscore the limitations of an across-the-board
disinfection approach to regulation.
As part of the multiple-barrier approach, EPA proposes source water
monitoring requirements that fulfill the need for a targeted risk-based
regulatory strategy by identifying those systems with source water
contamination and systems with high sensitivity to possible fecal
contamination--specifically undisinfected systems located in
hydrogeologically sensitive aquifers. EPA believes that the proposed
requirements provide a meaningful opportunity to reduce public health
risk for a substantial number of people served by ground water sources.
This section provides detailed information on current monitoring
requirements, monitoring data, indicators of fecal contamination, co-
occurrence issues, and describes the proposed requirements.
EPA proposes the following source water monitoring requirements for
systems that do not treat 4-log removal and/or inactivation of viruses:
(1) A system must collect a source water sample within 24 hours of
receiving notification of a total coliform-positive sample taken in
compliance with the TCR, and test for the presence of E. coli,
enterococci or coliphage; and (2) any system identified by the State as
hydrogeologically sensitive through a sensitivity assessment (see
Sec. 141.403) must conduct routine monthly monitoring, during the
months the system supplies water to the public, and analyze for E.
coli, enterococci or coliphage. In either case, if any sample is fecal
indicator-positive, the system would have to notify the State
immediately and then the system must take corrective action.
Currently, all systems must comply with the TCR (see section
I.B.1.) and the MCL for nitrates and nitrites. In
[[Page 30228]]
addition, CWSs and NTNCWSs must monitor at the entrance of the
distribution system for 15 additional inorganic chemicals associated
with an MCL (e.g., antimony, arsenic) and sometimes other inorganic
chemicals not associated with an MCL (calcium, orthophosphate, silica,
sodium, sulphate; 40 CFR 141.23(b) and (c)). Systems will also have to
comply with the Stage 1 DBPR, if they use a chemical disinfectant. CWSs
must additionally monitor for certain organic chemicals and certain
radionuclides. Ground water systems under the direct influence of
surface water must satisfy the requirements of the SWTR and IESWTR.
Microbial monitoring plays an important role in detecting fecal
contamination in source waters, as well as in assessing best management
practices, including in-place disinfection adequacy and distribution
system integrity. It is the most direct way to determine the presence
of fecal contamination. However, because of limitations on sample
volume, monitoring frequency, and the species of microorganisms that
can reasonably be monitored, non-detection of a fecal indicator does
not necessarily mean fecal contamination is absent (see Tables III-2
and 3).
2. Indicators of Fecal Contamination
Two approaches for determining whether a well is contaminated are
to monitor for the presence of either specific pathogens or more
general indicators of fecal contamination. Monitoring for individual
pathogens, however, is impractical because the large number and variety
of pathogens require extensive sampling and numerous analytical
methods. This is a process which is extremely time-consuming,
expensive, and also technically demanding. Moreover, methods are not
available for some pathogens and pathogen concentrations in water are
usually sufficiently small so as to require analysis of large-volume
samples, which significantly increases analytical costs. For these
reasons, EPA is focusing on indicators of fecal contamination as a
screening tool rather than on individual pathogens themselves. The
Agency is considering several promising fecal indicators: E. coli,
enterococci, somatic coliphage, and male-specific coliphage. Because
these indicators are closely associated with fecal contamination, EPA
believes that even a single positive sample should require urgent State
notification and other follow-up activities.
EPA considered three bacterial microorganisms as indicators of
fecal contamination: E. coli, enterococci, and C. perfringens. E. coli
and enterococci are both closely associated with fresh fecal
contamination and are found in high concentrations in sewage and
septage. Analytical methods are commercially available, simple,
reliable, and inexpensive. E. coli is monitored under the TCR, and E.
coli and enterococci are recommended by EPA as indicators for fecally
contaminated recreational waters. A drawback is that these two groups
may die out more quickly or be less mobile in the subsurface
environment than some waterborne pathogens.
As with E. coli and enterococci, C. perfringens is common in sewage
(about 10 \6\ organisms per liter) and is associated with fecal
contamination. Methods of detection are commercially available, simple,
reliable, and relatively inexpensive. C. perfringens forms protective
spores (endospores), and these spores survive much longer in some
environments than most pathogens. Thus, these spores may be present in
old fecal contamination where fecal pathogens are no longer viable. EPA
rejected C. perfringens as an indicator of fecal contamination for GWSs
based on co-occurrence data showing that the organism is seldom present
in ground water when other fecal indicators are present (Lieberman et.
al., 1999).
Enteric viruses, much smaller in size than bacteria such as E.
coli, may be more mobile than bacteria because they can slip through
small soil pores more rapidly. Thus, viral pathogens may sometimes be
present in ground water in the absence of bacterial indicators of fecal
contamination. However, other factors such as sorption to soil and
aquifer particles are also important in affecting the relative
transport of viruses and bacteria in ground water.
The coliphage are viruses that infect the bacterium E. coli.
Because they do not often infect other bacteria, they (like E. coli)
are closely associated with recent fecal contamination. Because they
are viruses, their stability and transport within soil and under
aquifer environmental conditions may be similar to the fate and
transport of pathogenic viruses. There are two categories of
coliphage--somatic coliphage and male-specific coliphage. The somatic
coliphage are a heterogenous group that enters the cell wall of E.
coli. The male-specific (also called the F-specific) phage are those
that only enter through tiny hair-like appendages (pili) to the cell
wall.
There are issues about using coliphage as an indicator of fecal
contamination in small communities. Individuals do not consistently
shed coliphage. For example, Osawa et al. (1981) found that only 2.3%
of infected individuals shed male-specific phage. Thus, the occurrence
of these viruses in small septic tanks, which is an important source of
fecal contamination in ground water wells, is uncertain. The issue of
frequency and abundance is important because a primary source of fecal
contamination in wells is thought to be nearby leaking septic tanks.
To answer this question, EPA funded a study to determine (Deborde,
1998, 1999) the frequency and density of coliphage occurrence in
household septic tanks. Deborde (1998) collected and analyzed a sample
from each of 100 sites in the Northwest and from each of 12 sites in
the Midwest (3), Southwest (3), Northeast (3), and Southeast (3). All
112 samples were analyzed for male-specific coliphage, while 33 were
also analyzed for somatic coliphage. Table III-1 shows that male-
specific coliphage are present in about one-third of the septic tank
samples, while somatic coliphage are present in two thirds of the
samples tested. However, when found, the male-specific coliphage are
present at a slightly higher level. The number of possible people per
household (and therefore the number of virus sources) varied from one
to seven, with an average of 2.8. In the next phase of the study,
Deborde (1999), selected ten of the 112 sites (five coliphage-positive,
five coliphage-negative) and collected three quarterly samples from
each. The data indicate that significant changes in density occur over
time. For the male-specific phage, the number of positive sites was
40%, 60% and 40% for quarter 2, 3, and 4, respectively. For the somatic
phage, the number of positive sites was 70%, 80% and 50% during these
same three quarters. As in the first phase, somatic phage were detected
more frequently and the male-specific phage were (when detected) more
abundant.
The data indicate that household septic tanks often (50-80%)
contain measurable levels of somatic coliphage, suggesting that the
somatic coliphage may be an appropriate indicator of fecal
contamination in nearby source waters. However, the male-specific
coliphage were present in the septic tanks in slightly less than half
the sites at any one time. Based on these data, male-specific phage may
not be suitable for detecting fecal contamination in source waters if
the most likely contamination source is a household septic tank.
[[Page 30229]]
Table III-1.--Frequency and Density of Coliphage In Household Septic
Tanks, Preliminary Results (Deborde, 1998)
------------------------------------------------------------------------
Coliphage Presence Density \1\
------------------------------------------------------------------------
Male-specific................. 36% (44/112)..... 9.7 x 10 \5\ PFU
\1\/L
Somatic....................... 67% (22/33)...... 1.3 x 10 \5\ PFU
\1\ /L
------------------------------------------------------------------------
\1\ Plaque-Forming Units (PFU).
Analytical methods for coliphage are available and are far less
expensive than methods for pathogenic virus detection. However, the
coliphage detection methods are still somewhat more expensive than
those for the common indicator bacteria. EPA is in the process of
funding the development of more sensitive, less expensive analytical
methods for the somatic and male-specific coliphage.
EPA also considered methods using polymerase chain reaction (PCR)
for identifying specific viruses. PCR amplifies the nucleic acid of the
targeted virus, which then can be detected and identified by various
procedures. An advantage of this method over those for coliphage is
that it can identify the presence of specific viruses pathogenic to
humans. Methods using PCR may be specific, sensitive, and much more
rapid than other methods for pathogenic virus. However, current PCR
technology cannot yet determine whether a virus is viable or infectious
and is significantly more expensive than the culture methods for the
above fecal indicators (currently about $250-300 per sample). EPA
expects substantial reductions in this cost as the method is further
developed. Nevertheless, in spite of the current limitations of PCR, a
positive result in a ground water sample would strongly imply that a
pathway exists for virus contamination of ground water.
EPA did not consider total coliform bacteria or heterotrophic
bacteria as fecal indicators because both groups grow naturally in soil
and water, and thus are not specific indicators of fecal contamination.
According to a survey of ground water data by the AWWARF study (see
Table II-6), C. perfringens was only detected in one of 57 samples
(1.8%). Thus, EPA eliminated this organism from consideration. See
Tables III-2 and 3 for occurrence data on candidate indicators.
Table III-2.--Presence/Absence of Indicators at Enterovirus-Positive Sites (Generally, One Sample/Site)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Number of Enterococci or
positive Total E. coli or fecal Somatic phage F-specific
Study enterovirus coliforms fecal streptococci (100 L) phage (100 L)
sites (100 mL) coliforms (100 mL)
--------------------------------------------------------------------------------------------------------------------------------------------------------
AWWARF Study............................................ 22 4 NA \1\ 2 \2\ 0 \2\ 2 (3)
Missouri Alluvial Study................................. 11 5 3 5 1 0
Missouri Ozark Plateau.................................. 10 0 0 0 0 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Only 11 enterovirus-positive sites tested.
\2\ 15 liter samples.
Table III-3.--Data From EPA/AWWARF Study. Number of Times Indicator Was Positive in 12 Monthly Samples at Enterovirus-Contaminated Sites \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Somatic F-specific
Enterovirus-positive site ( \1/12\ pos) Total coliform- E. coli positive Enterococci- coliphage- coliphage
positive positive positive \2\ positive \2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
029...................................................... 12 12 12 12 11
031...................................................... 12 6 5 9 3
047...................................................... 12 10 12 12 4
061...................................................... 11 11 10 11 8
091...................................................... 10 3 5 12 0
097...................................................... 5 0 1 4 0
099...................................................... 2 0 1 0 1
----------------------------------------------------------------------------------------------
Total................................................ 64 42 46 60 27
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Sample volume: bacteria 300 mL; coliphage most between 10-100L; enterovirus: average of 6,037 L.
\2\ Host for somatic coliphage: E. coli C; host for F-specific coliphage: WG49.
The data strongly shows that a single negative sample is usually
not sufficient to demonstrate the absence of fecal contamination, and
that repeated sampling is necessary. Based on the data, EPA does not
believe that one fecal indicator is clearly superior to the others.
The coliphage sample volume in the studies in Table III-3 ranged
from 10L to 100L (compared to 100-300 mL for the bacterial indicators).
EPA believes that it would be unreasonable to expect systems to collect
and transport these high water volumes. However, as stated earlier,
several sensitive coliphage methods have been developed that can be
used with a more reasonable volume (100-1000 mL).
Thus, for the reasons indicated earlier, EPA is proposing E. coli,
coliphage and enterococci as appropriate monitoring tools for source
water. Because these three fecal indicators are closely associated with
fecal contamination, the Agency believes that a single source water
positive E. coli, coliphage or enterococci sample is sufficient to
consider the source water as fecally contaminated. Repeated sampling is
proposed for routine monitoring (described in the next section) since
it may take more than one sample to identify intermittent
contamination. Additional support for this approach is provided by
Christian and Pipes (Christian and Pipes, 1983), who found that
coliforms follow a lognormal distribution pattern in small distribution
systems (i.e., coliforms are not uniformly distributed). EPA has no
reason to suspect that this non-uniform pattern should be different in
source waters. Only one additional sample is proposed after triggered
monitoring (described in the next section) since the
[[Page 30230]]
sample is taken immediately after an indication of contamination.
The Agency recognizes that errors in sample collection and testing
may contaminate a sample, and therefore would allow the State to
invalidate such samples, on a case-by-case basis, in the same manner
required under the TCR (141.21(c)(1)(i) and (iii) for invalidating
total coliform samples. However, EPA believes that errors in sample
collection rarely lead to contamination. This is based on a study by
Pipes and Christian (Pipes and Christian, 1982), where water samplers
and other individuals tried to contaminate 111 sample bottles
containing 100-mL of sterile dechlorinated tap water by placing a
finger into the mouth of each bottle and shaking the bottle vigorously
for about 5 seconds. Only 5.4% of the samples were found to contain
total coliforms.
Thus, the Agency believes that States should invalidate positive
samples sparingly. Under the GWR, the State would be allowed to
invalidate a positive source water sample if (1) the laboratory
establishes that improper sample analysis caused the positive result or
(2) the State has substantial grounds to believe that a positive result
is due to a circumstance or condition which does not reflect source
water quality, documents this in writing, and signs the document. In
this case, another source water sample must be taken within 24 hours of
receiving notice from the State.
3. Proposed Requirements
a. Routine Source Water Monitoring
EPA stated in the previous section on hydrogeology that a State
would be required to determine the hydrogeological sensitivity of each
system not treating to 4-log inactivation or removal of viruses. If the
State determines that the well(s) serving such a system draws water
from a sensitive aquifer, that system would be required to collect a
source water sample each month that it provides water to the public and
test the sample for the fecal indicator specified. If any sample
contains a fecal indicator, the system would be required to notify the
State immediately and address the contamination within 90 days unless
the State has approved a longer schedule (see Sec. 141.404).
Under the GWR, if a system detects no fecal indicator-positive
samples after 12 monthly samples, the State would be allowed to reduce
routine source water monitoring to quarterly. The State would be
allowed, after the first year of monthly samples, to waive source water
monitoring altogether for a system if the State determines that fecal
contamination of the well(s) is highly unlikely, based on sampling
history, land use pattern, disposal practices in the recharge area, and
proximity of septic tanks and other fecal contamination sources. PWSs
that do not operate year-round would need to conduct monthly sampling
for more than one year to collect the twelve monthly samples. EPA
requests comment on allowing such systems to monitor monthly for only
one seasonal period when the system is in operation.
b. Source Water Sample After a Total Coliform-Positive Under the TCR
EPA proposes that when a non-disinfecting ground water system is
notified that a sample is total coliform-positive under the TCR, that
system would have to collect, within 24 hours of being notified, at
least one source water sample. This requirement would be in addition to
all monitoring and testing requirements under the TCR. The source water
sample would be tested for either E. coli, coliphage or enterococci, as
determined by the State. A system that chooses to first test for total
coliforms in the source water, and then test any total coliform-
positive culture for E. coli would meet the requirement.
If any sample is E. coli-positive, coliphage-positive or
enterococci-positive, the system would be required to meet
Sec. 141.404. EPA believes that a total coliform-positive sample in the
distribution system, followed by a fecal indicator-positive sample in
the source water, indicates a serious contamination problem.
The Agency would allow the State to waive source water monitoring
for any system, on a case-by-case basis, if the State determines that
the total coliform-positive is associated solely with a distribution
system problem. In this case, a State official would be required to
document the decision, including the rationale for this decision, in
writing, and sign the document.
c. Confirmation of Positive Source Water Sample
The Agency recognizes that false-positive results may occasionally
occur with most microbial methods (i.e., a non-target microbe is
identified by the method as a target microbe). For example, the false-
positive rate for E. coli is 7.2% for the E*Colite Test, 2.5% for the
ColiBlue24 Test, and 4.3% for the membrane filter test using MI Agar.
Therefore, EPA would allow the State to invalidate a positive
source water sample where a laboratory establishes that improper sample
analyses caused the positive result or if the State has substantial
grounds to believe that a positive result was due to a circumstance or
condition that did not reflect source water quality and documents this
in writing. For example, a State may invalidate a positive source water
sample if a subsequent validation step for the same sample fails to
confirm the presence of the fecal indicator being used. These
provisions are consistent with the invalidation criteria under the TCR
(40 CFR 141.21(c)).
EPA believes that, in the interest of public health, a positive
sample by any of the methods listed in Table III-4 should be regarded
as a fecal indicator-positive source water sample. This assumption is
supported by the Pipes and Christian study (Pipes and Christian, 1982)
study mentioned previously, which shows that sample collector handling
error is rarely a cause of fecal contamination. Nevertheless, the
Agency recognizes that contamination during sampling and analysis may
occur, albeit rarely, and is proposing to allow the State to invalidate
a fecal indicator-positive in a routine monitoring sample under certain
circumstances in the manner described in this section. EPA is also
proposing to allow confirmation of a fecal indicator-positive routine
source water sample. Specifically, the rule would permit the State to
allow a system to waive compliance with the treatment technique in
Sec. 141.404, after a single fecal indicator-positive source water
sample on a case-by-case basis, if--
(1) The system collects five repeat source water samples within 24
hours after being notified of a source water-positive result;
(2) The system has the samples analyzed for the same fecal
indicator as the original sample;
(3) All the repeat samples are fecal indicator-negative; and
(4) All required source water samples (routine and triggered)
during the past five years were fecal indicator-negative.
Under this approach, a system would not necessarily have to comply
with the specified treatment requirements on the basis of a single,
isolated fecal indicator-positive sample if all additional monitoring
showed that no problem exists. The Agency believes that this limited
level of confirmation would not undermine public health protection.
Conversely, the Agency believes that two fecal indicator-positive
source water samples at a site provides strong evidence that the source
water has been fecally contaminated.
The Agency is also proposing that a total coliform-positive sample
in the
[[Page 30231]]
distribution system accompanied by a fecal indicator-positive source
water sample be sufficient grounds for requiring compliance with the
treatment requirements. The Agency argues that it would be unreasonable
to expect a sample collector to accidently contaminate two samples
taken at least one day apart, and also contends that the likelihood of
a false-positive result occurring in both of two samples is much lower
than in a single sample. Thus, the Agency believes that, in this
circumstance, there is a significant probability that the source water
is indeed fecally contaminated. Moreover, the Agency notes that, under
the TCR, two consecutive total coliform-positive samples, one of which
is E. coli-positive, is sufficient grounds for an acute violation of
the MCL for total coliforms. For these reasons, EPA believes that it is
reasonable to require a system with a total coliform-positive sample in
the distribution system followed by a fecal indicator-positive source
water sample to comply with the treatment requirements. However, EPA
also recognizes that, by itself, a positive total coliform result is
not always an indication of fecal contamination (even if the sample
result is not a false positive). EPA requests comment on waiving
compliance of the treatment techniques after a single positive
triggered monitoring source water sample based upon five negative
repeat samples as described previously in this section.
4. Analytical Methods
EPA proposes to approve the following methods (listed in 141.403),
with the sample volume of 100 mL, for source water monitoring of E.
coli, enterococci and coliphage. A system would have to use one of
these methods. Most of the proposed analytical methods for E. coli for
source water monitoring are consensus methods described in Standard
Methods for the Examination of Water and Wastewater (19th and 20th
ed.). The three E. coli methods that are not consensus methods are
newly developed: MI agar (a membrane filter method), the ColiBlue 24
test (a membrane filter method) and the E*Colite test (a defined
dehydrated medium to which water is added). EPA has already evaluated
and approved these three methods for use under the TCR. Information
about these methods is available in the Federal Register (63 FR 41134-
41143, July 31, 1998; 64 FR 2538-2544, January 14, 1999) and in the
EPAWater Docket. Of the three enterococci methods, two are consensus
methods in Standard Methods; while the third (Enterolert) was described
in a peer-reviewed journal article (Budnick et al., 1996). The
description for each of the proposed E. coli and enterococci methods
state explicitly that the method is appropriate for fresh waters or
drinking waters.
EPA is proposing the approval of two newly developed coliphage
methods for detecting fecal contamination.
The Agency has conducted performance studies on the two proposed
methods, using ten laboratories: a new two-step enrichment method and a
single-agar layer method used for decades, but recently optimized for
ground water samples. For the two-step enrichment method, using 100-mL
spiked water samples (reagent water and ground water) and two E. coli
hosts (CN-13 and Famp), laboratories detected one plaque-
forming unit (PFU) 60-90% of the time. For the optimized single-agar
layer method, using the same water type and volume (but higher
coliphage spike) and same two E. coli hosts, recoveries ranged from 61%
to 178%, based upon a coliphage spike level determined by a standard
double-agar layer test.
Based upon the results of performance testing, EPA believes that
these two coliphage tests are satisfactory for monitoring ground water
in compliance with this rule. The two test protocols and study results
are available for review in EPA's Water Docket.
EPA is proposing requiring that systems collect and test at least a
100-mL sample volume. The Agency recognizes that a 1-L sample volume
will provide ten times more sensitivity than a 100-mL sample. However,
the Agency also understands that the greater sample volume would also
weigh ten times more, and thus cost more to ship to a laboratory. Data
exists that indicate more frequent smaller-volume samples are better in
detecting fecal contamination than a smaller number of high volume
samples (Haas,1993). AWWARF is funding a study on this issue, and data
should be available shortly. The Agency requests comment on the most
appropriate sample volume.
For any of the methods described previously, the maximum allowable
time between ground water sample collection and the initiation of
analysis in the certified laboratory, is 30 hours. This would be
consistent with the TCR. The Agency would prefer a shorter time, but
believes that a sizable percentage of small systems have difficulty
getting their samples to a certified laboratory within 30 hours. In
addition, unlike the SWTR where the density is measured, EPA is
proposing in the GWR to require analysis for microorganism detection
alone. The Agency believes that the detection of an organism is less
sensitive to change than measurement of density, and thus a 30-hour
transit time would be reasonable.
5. Request for Comments
EPA requests comments on proposed indicators of fecal contamination
and analytical methods. In addition, EPA requests comments on the
following alternative approaches.
(a) Source Water Samples after an MCL Violation of the TCR
EPA requests comment on requiring a system that violates the MCL
for total coliforms, or detects a single fecal coliform/E. coli-
positive sample under the TCR, to collect five source water samples,
rather than a single source water sample as proposed. The Agency
believes this alternative approach would be reasonable, given that both
events are sufficiently important to require the system to notify the
State (and, for a MCL violation, the public) as opposed to a single
total coliform-positive sample which does not require notification.
Under this approach, systems would be required to collect five source
water samples within 24 hours for every MCL violation or positive E.
coli or fecal coliform sample in the distribution system and test them
for one of the EPA-specified fecal indicators. If any source water
sample were positive, the system would have to treat or otherwise
protect the drinking water. This monitoring requirement would be in
addition to requirements under the TCR.
(b) Sampling of Representative Wells
EPA recognizes that most CWSs have more than one well, raising the
question about whether the system would need to monitor all wells or
just one representative well. One approach would be to require a system
to sample all wells because this approach provides more reliable public
health protection. However, the Agency notes that wells belonging to a
system may vary in their sensitivity to fecal contamination.
If a system is drawing water from more than one well in a
hydrogeologically sensitive aquifer, EPA believes that all such wells
should be sampled routinely, unless the State can identify a single
representative well or, the well (or subset of wells) sensitive to
fecal contamination. If a system is required to collect a source water
sample as a result of a total coliform-positive sample in the
distribution system (triggered monitoring), EPA believes that all wells
should be sampled, unless the State can identify a single
representative well or the well (or
[[Page 30232]]
subset of wells) most vulnerable to fecal contamination. Alternatively,
if the total coliform-positive sample was found in a part of the
distribution system supplied by a single well, then it might be
acceptable to sample that specific well alone. The Agency seeks comment
on these alternatives and other approaches.
EPA recognizes that systems may have storage tanks or other water
holding tanks between the wellhead and the distribution system.
Therefore the Agency also requests comment on whether further
definition is needed for exactly where source water samples should be
taken; e.g., at the well, the tank, or at any point before the water
enters the distribution system. The Agency seeks comment on where
source water samples should be collected.
(c) Distribution System Monitoring for Fecal Indicators
One alternative approach for distribution system monitoring is to
augment total coliform/E. coli testing in the distribution system with
one or more additional fecal indicators. For example, under this
approach, a system would be required to monitor coliphage or
enterococci at the same frequency as it monitors for total coliforms.
This approach recognizes that fecal indicators differ in their
effectiveness in detecting fecal contamination, and that this
effectiveness may vary with environmental conditions. Thus, more than
one fecal indicator should stand a greater likelihood of detecting
fecal contamination than a single indicator (i.e., E. coli under the
TCR). This approach would be more expensive for systems, but may be
counterbalanced by the greater likelihood of detecting fecal
contamination. EPA seeks comment on this monitoring approach.
(d) Persistent Monitoring Non-Compliers
EPA requests comment on defining a persistent non-complier of
monitoring requirements and, specifically what any additional
monitoring, public notification or treatment requirements should
pertain to them.
(e) Monitoring of Disinfecting Systems
Some States currently require disinfected systems to monitor their
source water to ensure that the system would be protected against the
potential risk of fecal contamination in the event of a disinfectant
failure. The Agency requests comment on requiring a disinfected system
to test its source water periodically.
The Agency also requests comment on requiring all ground water
systems (including those that disinfect to 4-log removal/ inactivation
of viruses) to collect a source water sample after a total coliform-
positive in the distribution system (triggered monitoring). Systems may
want or need to change their disinfection practices or take other
source water protection actions based on discovering that their source
water is contaminated.
(f) Multiple Fecal Indicators
EPA is proposing to require ground water systems to monitor
coliphage, E. coli, or enterococci, as determined by the State, in the
source water. On March 13, 2000, the Drinking Water Committee of the
Science Advisory Board (DWCSAB) made a few recommendations to EPA
concerning a draft of this proposal.
The DWCSAB recommended unanimously, and the Agency is requesting
comment on, requiring monitoring for both bacterial and viral
indicators for both routine and triggered monitoring. Specifically, EPA
is requesting comment on whether systems that must monitor their source
water be required to monitor for both a bacterium (E.coli or
enterococci) and virus (male specific and somatic coliphage). As
discussed earlier, occurrence data show that fecal indicators differ in
their scope and this may vary with environmental conditions. The DWCSAB
noted that the scientific literature documents significant differences
between transport and survival of bacteria and viruses. Coliphage and
human viruses are smaller than bacterial indicators and thus under
certain conditions may travel faster through the ground than bacteria;
alternately, bacterial indicators are often at much higher
concentrations in fecal matter than coliphage, and thus may be a more
sensitive indicator than coliphage relatively near the contamination
source. The use of both bacteria and coliphage indicators could provide
better ability to detect fecal contamination and greater protection of
human health. However it would also entail a higher probability of
false positive results, and higher sampling costs to the systems.
The DWCSAB believed that the proposed indicators (E.coli,
enterococci, and coliphage) are appropriate. The DWCSAB noted that both
E. coli and enterococci are effective bacterial indicators. E. coli
methods may be more familiar to many laboratories which may be
advantageous. The enterococci may be somewhat hardier in terms of
environmental persistence and perhaps more fecal specific. The media
for enterococci is more selective and less subject to background growth
with regards to the viral indicators. The DWCSAB recommended both
somatic and male-specific coliphage be required when viral monitoring
of the source water is conducted because they will detect a larger
population of coliphage. The DWCSAB stated that laboratory methods are
available to detect both coliphages and that they believe that a method
can be made available to detect both coliphages on a single host (using
a single host such as E. coli C3000) so that it would not be necessary
to collect and test two samples for coliphage.
(g) Monitoring Frequency and Number of Samples To Identify Fecal
Contamination
As stated previously, the proposed rule would require systems with
sensitive wells to conduct monthly routine monitoring. The Agency
believes that monitoring more frequently than monthly would increase
the probability for detecting fecal indicator organisms sooner in a
fecally contaminated well. However, the Agency also recognizes that
more intensive monitoring could be overly burdensome to many small
systems. Less than monthly monitoring would likely delay fecal
contamination detection, and thus continue a possible health risk for a
longer time. EPA concludes that monthly monitoring is the most
appropriate balance between monitoring costs and prompt fecal
contamination detection.
The total number of samples needed to determine whether a ground
water is fecally contaminated depends on the fecal indicator used, the
sample volume, and the level and duration of fecal contamination in the
source water. Because the EPA/AWWARF study described in section II.C.2.
monitored contaminated wells repeatedly, the results of this study were
used to assess the likelihood (95%, 99%, 99.9% confidence) of detecting
fecal contamination with different indicators, number of samples and
level of fecal contamination actually in the ground water. The Agency
then determined the minimum number of samples necessary to detect
contamination, allowing for a small percentage of samples where fecal
contamination is not detected. The EPA/AWWARF study operated in two
phases. In Phase I, the EPA/AWWARF researchers identified a set of 93
wells thought to be vulnerable to fecal contamination. In Phase II, the
researchers conducted further analysis, including monthly monitoring
for virus and bacteria, on a subset of 23 of the Phase I wells which
demonstrated total coliform and/or fecal bacteria contamination and on
an additional 7
[[Page 30233]]
wells chosen for their unique physical or chemical characteristics.
From the wells tested in Phase II of the EPA/AWWARF study, seven
sites tested positive for enterovirus in at least one sample of the
twelve collected during the year. These seven waters are considered to
be representative of ground water that are highly fecally contaminated
at least part of the year. In such waters, a good indicator should be
present in almost every sample, therefore, the number of non-detects
should be very low. Combining the monthly results for these seven
waters, there are 84 results for each indicator. Table III-5 shows the
proportion of positives among the 84 results for each of four
indicators.
Table III-5.--Indicator Performance in Seven Highly-Contaminated Waters
------------------------------------------------------------------------
Samples
positive
Indicator (percent)
(N=84)
------------------------------------------------------------------------
E. coli.................................................... 50
Enterococci................................................ 54.8
Somatic Coliphage.......................................... 71.4
F-Specific Coliphage....................................... 32.1
------------------------------------------------------------------------
N = number of samples.
If P is the probability of a positive sampling result (a detect)
for a single indicator sample assay, then the probability of at least
one positive result for N repeated independent samples is 1-(1-
P)N. The probability of ``N'' non-detects is (1-
P)N.. Table III-6 shows the probabilities of ``N'' non-
detects for the same indicators as a function of the number of
independent sample assays (N).
Table III-6.--Probability of Non-Detects in Ground Water That is Highly Fecally Contaminated at Least Part of the Year (Where `N' Is the Number of
Independent Assays)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Number of samples (N)
--------------------------------------------------------------------------------------------------
Indicator \1\ N = 1 N = 2 N = 4 N = 6 N = 12 N = 24 N* 5 N*1 1 N* 0.1
(percent) (percent) (percent) (percent) (percent) (percent) percent percent percent
--------------------------------------------------------------------------------------------------------------------------------------------------------
E.coli............................................... 50 25 6.3 1.6 0.1 0.1 5 7 10
Enterococci.......................................... 45.2 20.5 4.2 0.9 0.1 0.1 4 6 9
Somatic Coliphage.................................... 28.6 8.2 0.7 0.1 0.1 0.1 3 4 6
F-Specific Coliphage................................. 67.9 46 21.2 9.8 1.0 0.1 8 12 18
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sample volume was 300 ml for E. coli and enterococci, 10-100L for coliphage
N* = Smallest number of samples for which the error rate is less than or equal to the specified percentage (5%, 1%, 0.1%).
Table III-6 shows that six to18 source water samples are needed,
depending on the fecal indicator (and sample volume used), to determine
with a 99.9% probability that a fecal indicator positive will be
detected in ground water that is highly contaminated at least part of
the year.
A similar analysis was conducted using the results for the 10
waters that tested positive for E. coli at least once (N=12), but
negative for enterovirus. These waters were defined as moderately
contaminated during at least part of the year. Because these waters
probably do not contain enteroviruses at easily detectable levels, the
incidence of waterborne disease is probably less. Table III-7 shows the
probabilities of ``N'' non-detects for different numbers of independent
sample assays (N).
Table III-7.--Probability of Non-Detects in Ground Water That is Moderately Fecally Contaminated at Least Part of the Year (Where `N' is the Number of
Independent Assays)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Number of samples (N)
--------------------------------------------------------------------------------------------------
Indicator N = 1 N = 2 N = 4 N = 6 N = 12 N = 24 N* 5 N* 1 N* 0.1
(percent) (percent) (percent) (percent) (percent) (percent) percent percent percent
--------------------------------------------------------------------------------------------------------------------------------------------------------
E.coli............................................... 71.7 51.4 26.4 13.5 1.8 0.1 9 14 21
Enterococci.......................................... 67.5 45.6 20.8 9.55 0.9 0.1 8 12 18
Somatic.............................................. 72.5 52.6 27.6 14.5 2.1 0.1 10 15 22
F-Specific........................................... 96.7 93.4 87.3 81.6 66.6 44.3 89 136 204
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sample volume was 300 ml for E. coli and enterococci, 10-100L for coliphage
N* = Smallest number of samples for which the error rate is less than or equal to 5.0%, 1% and 0.1%.
Table III-7, shows that 8 to 89 samples are needed, depending on
the indicator selected, to determine with a 95% probability that a
fecal indicator positive will be detected in a well that is moderately
contaminated at least part of the year.
Based on the data described previously and statistics, EPA
concludes that, given a margin of safety for the analysis, 12 samples
would be sufficient for determining the presence of fecal contamination
in sensitive wells. For systems operating year round, 12 monthly
samples will provide data throughout the year, increasing the
likelihood of detecting the seasonal presence of fecal contamination.
EPA requests comment on the monitoring approach discussed
previously and the analysis and the assumptions used.
(h) Triggered Monitoring in Systems Without a Distribution System
EPA believes that circumstances exist that might not require the
collection of a source water sample after a total coliform-positive
sample in the distribution system. For example, if an
[[Page 30234]]
undisinfected system does not have a distribution system, any sample
taken for compliance with the TCR is essentially a source water sample.
Therefore, the Agency is requesting comment on whether to allow States
to waive ``triggered'' source water sampling for systems without
distribution systems if the system is also taking TCR samples at least
quarterly. If the total coliform-positive sample from the distribution
system is fecal coliform-or E. coli-positive, the system would be
required to meet the treatment technique. There might also be
provisions for repeat sampling in this case.
(i) Routine Monitoring in Systems Without a Distribution System.
EPA requests comment on whether to allow States to substitute TCR
monitoring for routine monitoring in hydrogeologically sensitive
systems if the system does not have a distribution system and takes at
least one total coliform sample per month under the TCR for every month
it provides water to the public. Such a system would be monitoring
source water under the TCR. The State would be allowed to reduce or
waive monthly monitoring after twelve negative monthly samples. The
rule would require a system that has a total coliform-positive sample
that is also E. coli (or fecal coliform)-positive to meet the treatment
requirements in Sec. 141.404.
(j) Source Water Monitoring for All Systems
EPA is proposing to require source water monitoring requirements
for systems that do not treat to 4-log inactivation or removal of
viruses and have either a total coliform-positive sample taken in
compliance with the TCR, or any system identified by the State as
hydrogeologically sensitive. On March 13, 2000 the Drinking Water
Committee of the Science Advisory Board (DWCSAB) reviewed this issue
and made several recommendations to EPA concerning a draft of this
proposal. The DWCSAB raised concerns that under this approach many
untreated ground water systems will not be monitored at the source,
particularly in light of available occurrence data indicating
contamination between 4 and 31 percent of ground water systems, a
number of which many not be located in hydrogeologically sensitive
areas. DWCSAB unanimously recommended that all ground water systems
monitor for both bacterial and viral indicators. EPA requests comment
on whether routine source water samples should be required for all
ground water systems that do not notify the State that they achieved 4-
log inactivation or removal of virus. EPA also requests comment upon
the appropriate frequency (monthly or quarterly) for routine monitoring
if it were required for all systems. EPA also requests comment upon
whether this monitoring should be performed in conjunction with
sanitary surveys so as to provide data for the sanitary survey and to
reduce the capacity burden on laboratories by taking advantage of the
phased timing of sanitary surveys (every 3 years for CWSs and every 5
years for NCWs).
E. Treatment Techniques for Systems With Fecally Contaminated Source
Water or Uncorrected Significant Deficiencies
1. Overview and Purpose
EPA proposes that a public ground water system with uncorrected
significant deficiencies or fecally contaminated source water must
apply a treatment technique or develop application for a longer State-
approved treatment technique within 90 days of notification of the
problem. Under the SDWA, the State may extend the 90 day deadline up to
two additional years if the State determines that additional time is
necessary for capital improvements (SDWA, 1412(b)(10)). As part of this
requirement and in consultation with the State, systems must eliminate
the source of contamination, correct the significant deficiency,
provide an alternate source water, or provide a treatment which
reliably achieves at least 99.99 percent (4-log) inactivation or
removal of viruses before or at the first customer. Ground water
systems which provide 4-log inactivation or removal of viruses will be
required to conduct compliance monitoring to demonstrate treatment
effectiveness.
EPA is proposing 99.99% (4-log) virus inactivation or removal as
the minimum level of treatment since it is the level required of
surface water systems under the SWTR and because, the World Health
Organization (WHO) states that disinfection processes must achieve at
least 4-log reduction of enteric viruses (WHO, 1996). Which treatment
technique approach is chosen will depend on existing State programs,
policies or regulations. States must describe in their primacy
application the treatment technique they will require and under what
circumstances. If the treatment technique is not provided within 90
days, or if it is not implemented by the system in accordance with
schedule requirements, the system is in violation of the treatment
technique requirements of the GWR.
States and systems can select a number of treatment technologies to
achieve 4-log virus inactivation or removal. The treatment technologies
which have demonstrated the ability to achieve 4-log virus inactivation
are chlorine, chlorine followed by ammonia (chloramines), chlorine
dioxide, ozone, ultraviolet radiation (UV) and anodic oxidation.
Reverse osmosis (RO) and nanofiltration (NF) have demonstrated the
ability to achieve 4-log removal of viruses.
The Agency is also proposing requirements for systems that treat to
monitor the disinfection and State notification requirements any time a
system fails to disinfect to 4-log inactivation or removal of viruses.
As part of this proposal, systems serving 3,300 or more people per day
must monitor the disinfection continuously. Systems serving fewer than
3,300 people per day must monitor the disinfection by taking daily grab
samples. When a system continuously monitors chemical disinfection, the
system must notify the State any time the residual disinfectant
concentration falls below the State-determined residual disinfectant
concentration and is not restored within four hours. When a system
monitors chemical disinfection by taking daily grab samples the system
must maintain the State-determined residual disinfectant concentration
in all samples taken. If any sample does not contain the required
concentration, the system must take follow-up samples every four hours
until the required residual disinfectant concentration is restored. The
system must notify the State any time the system does not restore the
disinfectant concentration to the required level within 4 hours.
a. Background
A key element of the multiple-barrier approach is disinfection
where fecal contamination or significant deficiencies are not or cannot
be corrected. EPA recognizes that the GWR must provide system-specific
flexibility due to the diverse configuration and variability of the
numerous public ground water systems in operation and allow for State-
specific flexibility. Therefore, the proposed treatment technique
requirements are designed to support the multiple-barrier approach, yet
provide flexibility to meet system-specific concerns.
EPA recognizes that States use varying approaches and that a
State's preferred approach comes from extensive experience in dealing
with uncorrected significant deficiencies and
[[Page 30235]]
contaminated source water. States may require systems to take differing
approaches to providing treatment techniques, depending upon many
factors, including the system's configuration, or State policies or
regulations. Therefore, the proposed GWR attempts to build on the
strengths of existing State programs, yet provide requirements which
ensure safe drinking water for all consumers. Under the proposed GWR,
States may require systems to eliminate the source of contamination,
correct the significant deficiency, provide an alternate source water,
or provide a treatment which reliably achieves at least 99.99 percent
(4-log) inactivation or removal of viruses before or at the first
customer. Ground water systems which provide 4-log inactivation or
removal of viruses will be required to conduct compliance monitoring to
demonstrate treatment effectiveness. For example, a State may have a
policy or regulation requiring a system to consider an alternative
source of safe drinking water before considering the use of
disinfection. Alternatively, the State may require the system to
disinfect to 4-log virus inactivation without first considering the use
of corrective BMPs or alternative sources of safe drinking water. The
approach the State will use to require a treatment technique for
uncorrected significant deficiencies or fecally contaminated source
water must be described in the State's primary enforcement application
(primacy). EPA expects a State to build upon existing ground water
programs to meet today's proposed regulations. In any case, systems
which do not provide the appropriate State-determined treatment
technique within the 90 day deadline, and do not have a State-approved
plan in place for complying with the treatment technique requirement
within 90 days, are in violation of the treatment technique
requirements of the GWR.
b. Corrective Action Background Information
This section presents background information used by EPA to develop
the proposed treatment technique requirements for ground water systems
with uncorrected sanitary survey significant deficiencies or fecally
contaminated source water. Specifically discussed is information
related to current State treatment technique requirements, and the
protectiveness of treatment techniques, as well as a discussion of
disinfection as it relates to uncorrected significant deficiencies and
fecally contaminated source water.
i. Alternative Sources of Safe Drinking Water
Limited data exists on the effectiveness of systems using an
alternative source as a treatment technique against uncorrected
significant deficiencies or fecally contaminated source water. However,
since many States require a wide range of BMPs to be followed prior to
placing an alternative source into service, it is believed that this
treatment technique would be effective. In addition, some States
require the local hydrogeology or sources of contamination to be
considered for all new sources of drinking water, and would, therefore,
provide some assurance that an alternative source as a treatment
technique is effective. Several States require systems with source
water contamination to provide an alternative source, if possible.
ii. Background Information on Eliminating the Source of Contamination
As with the effectiveness of providing alternative source water as
a treatment technique for uncorrected significant deficiencies or
fecally contaminated source water, limited data exists on the
effectiveness of eliminating the source of contamination as a treatment
technique. The report on the Analysis of Best Management Practices for
Community Ground Water Systems Survey Data Collected by the Association
of State Drinking Water Administrators (ASDWA, 1998) provides
information on the effectiveness of BMPs in reducing total coliform
positives, however, it does not address those BMPs used in response to
a source water fecal contamination event. The report does show that
when correcting significant deficiencies, a significant pairwise
association exists in reducing both total and fecal coliform positive
samples. A wide range of State requirements exist for the use of BMPs,
with some States requiring the use of one or more BMPs in response to
contamination events.
iii. Disinfection
Under today's proposal, disinfection is defined as the inactivation
or removal of fecal microbial contamination. As noted earlier,
corrective actions to met the GWR treatment technique includes
disinfection. Chemical disinfection of viruses involves providing a
dosage of a disinfectant for a period of time for the purposes of
inactivating the viruses. For most treatment strategies, the level of
inactivation achieved varies depending on the target microorganism,
residual disinfectant concentration, ground water temperature and pH,
water quality and the contact time. The CT value is the residual
disinfectant concentration multiplied by the contact time.
Specifically, the contact time is the time in minutes it takes the
water to move between the point of disinfectant application and a point
before or at the first customer during peak hourly flow. The
concentration is the residual disinfectant concentration in mg/L before
or at the first customer, but at or after the point the contact time is
measured. A system compares the CT value achieved to the published CT
value for a given level of treatment (e.g., 4-log inactivation of
viruses) to determine the level of treatment attained. As long as the
CT value achieved by the system meets or exceeds the CT value needed to
inactivate viruses to 4-log, the system meets the treatment technique
requirement.
Four-log virus inactivation can also be achieved by UV
disinfection, which differs from some other treatment technologies, in
that providing a residual concentration is not possible. When using UV
disinfection, a light dosage is applied to the water to target the
attainment of IT values (measured in mWs/cm \2\). IT is the light
irradiance (measured in mW/cm \2\) to which the target organisms are
exposed, multiplied by the time for which the irradiance is applied
(measured in seconds). A system compares the IT value achieved to the
published IT value for a given level of treatment (e.g., 4-log
inactivation of viruses) to determine the level of treatment attained.
Systems required to disinfect with UV disinfection under the GWR must
provide 4-log inactivation of viruses at a minimum. As long as the
system attains IT values necessary for 4-log virus inactivation, the
system meets the treatment technique requirement.
Removal, in the context of treatment of microbially contaminated
ground water, is the physical straining of the microbial contamination,
and is usually accomplished through filtration. For the purposes of
disinfection of microbially contaminated ground water, removal is
accomplished by membrane processes. Membrane processes physically
remove viruses from the water based on the size of the virus and the
size of the membrane's pores. When the absolute size of the membrane's
pores (the molecular weight cut-off, or MWCO) are substantially smaller
than the diameter of the virus, removal of the virus can be achieved.
Therefore, membrane filtration technologies with MWCO substantially
less than the diameter of
[[Page 30236]]
viruses can be effective treatment technologies for 4-log virus
removal.
iv. State Requirements
EPA used the Baseline Profile Document for the Ground Water Rule
(USEPA, 1999f) to assess current State treatment technique
requirements. The EPA survey Ground Water Disinfection and Protective
Practices in the United States (US EPA, 1996a) was used where the
Baseline Profile Document for the Ground Water Rule (USEPA, 1999f)
lacked certain information. These data are important in illustrating
the wide range of State requirements that exists in ground water
systems. The GWR attempts to build on existing State practices and
provide State flexibility to address system-specific concerns.
Based on an analysis of information in the Baseline Profile
Document for the Ground Water Rule (USEPA, 1999f), there is great
variability nationwide in State statutes, regulations, and policies for
when and how systems must apply treatment techniques. The variability
ranges from 11 States requiring across-the-board disinfection, several
other States requiring systems to attempt to eliminate the real or
potential source of fecal contamination before considering
disinfection, to some States requiring systems with fecally
contaminated source water to provide an alternative source of safe
drinking water. Almost all of the States have statutes, regulations, or
policies for treatment techniques that define under what circumstances
treatment techniques are necessary. Twenty-eight of the 39 States which
do not require across-the-board disinfection require application of
treatment techniques based on the microbial quality of the water and 12
of the 39 require application of treatment techniques based on the
sanitary quality of the system.
How a system applies treatment techniques also varies considerably
from State to State. For example, 36 of the 50 States specify
requirements on the use of disinfectant residuals in the distribution
system, while five States require 4-log inactivation of viruses at the
source.
v. Disinfection Technologies
In ground water systems, 4-log inactivation of viruses can be
accomplished by disinfection with free chlorine, chloramines, chlorine
dioxide, ozone, on-site oxidant generation (anodic oxidation) or
ultraviolet radiation (UV). Reverse osmosis (RO) and nanofiltration
(NF) can achieve 4-log removal of viruses. Chlorine, chloramines,
chlorine dioxide, ozone, UV, RO and NF are all listed as small system
compliance technologies for the SWTR. EPA also suggests that small
systems consider on-site oxidant generation for SWTR compliance
purposes (US EPA, 1998c).
Chemical disinfection technologies are commonly used to provide
disinfection prior to distribution, and must attain specific CT values
(which vary depending on the technology) to achieve 4-log virus
inactivation. Free chlorine disinfection is the most commonly practiced
chemical disinfection technology, and requires a CT value of four to
provide 4-log inactivation of viruses at a water temperature of
15 deg.C, and a pH of 6-9 (USEPA, 1991a).
The required CT values for 4-log virus inactivation when using
chloramines or chlorine dioxide are higher than when using free
chlorine (Table III-8). The CT values for 4-log inactivation of viruses
at a pH of 6-9 and a temperature of 15 deg.C are 16.7 mg-min/L for
chlorine dioxide and 994 mg-min/L for chloramines (US EPA, 1991a). The
CT value for chloramines applies to systems which generate chloramines
by the addition of free chlorine, followed by the addition of ammonia.
This chloramine CT value for 15 deg.C was obtained by extrapolating CT
values from a study performed by Sobsey, et al, (1988) at 5 deg.C.
These CT values for chlorine and chloramines studied HAV, which,
compared to other viruses which occur in fecally contaminated ground
water, is relatively resistant to chlorine disinfection. The CT value
for chlorine dioxide was obtained from a study of chlorine dioxide
inactivation of HAV by chlorine dioxide at 5 deg.C (Sobsey, et al.,
1988). The CT value obtained in this study was adjusted to 15 deg.C,
and had a safety factor of two applied. Considering that chlorine
dioxide has a higher CT value than chlorine and due to site specific
situations, chlorine dioxide may not be a feasible disinfection
technology for all systems. Additional studies have been conducted
using free chlorine on Coxsackie virus B5 and poliovirus 1 (Kelly and
Sanderson, 1958), and information on these studies is provided in Table
III-8. Although the CT values for HAV were included in the guidance
manual to the SWTR intended for surface water systems, the CT values
are applicable to ground water systems, since they are based on
disinfectant residual (i.e., after demand) concentrations.
Many systems apply free chlorine disinfection in a contact basin
prior to distribution for virus inactivation, followed by ammonia
addition prior to distribution (to form chloramines) to protect the
water as it travels through the distribution system, since chloramines
provide a longer lasting residual than free chlorine. Due to the high
CT value for chloramines, some additional disinfection prior to
distribution would probably be needed.
A system that must disinfect may also need to increase the CT value
attained if the CT value attained does not achieve the 4-log
inactivation of viruses. Under some circumstances, this can be
accomplished by providing a higher disinfectant dosage (and hence, a
higher disinfectant residual), or a longer contact time (by providing
additional storage). Data from the CWSS (1995) suggests that many CWSs
(and some NCWSs) served by ground water may already have storage in
place and may be able to achieve 4-log virus inactivation without
additional storage. According to the CWSS, 59% of community ground
water systems have distribution system storage tanks, including 34% of
systems serving less than 100 people (CWSS, 1995). This number
increases to 95% for systems serving 10,001-100,000 people. Twenty-
eight percent of ancillary community ground water systems were found to
have storage. According to the CWSS, ancillary systems are those
systems for which providing drinking water is not their primary
business (e.g., restaurants).
Table III-8. Disinfection Studies Using Chlorine, Chlorine Dioxide and Chloramines on Viruses
--------------------------------------------------------------------------------------------------------------------------------------------------------
Studies conducted Effectiveness Additional notes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Log
Disinfectant Virus studied Reference & date removal CT Residual Comments
--------------------------------------------------------------------------------------------------------------------------------------------------------
Chlorine............................ HAV.................... Sobsey et al., 1988... 4 \1\ 4 Y safety factor = 3
Sobsey et al., 1988... 4 \1\ 30 Y pH = 10 safety factor
= 3
Coxsackie B5........... Kelly & Sanderson, 4 pH = 6, T = 28 deg.C
1958. c1.07
[[Page 30237]]
\1\ Poliovirus......... Kelly & Sanderson, 4 pH of 6-9, unless otherwise noted.
\2\ Table adapted from Technologies and Costs for Ground Water Disinfection (USEPA, 1993).
Ozone, unlike chlorine dioxide and chloramines, is a stronger
disinfectant than chlorine and would require less contact time (and
less storage) at a similar dosage (Table III-9) to inactivate viruses.
The CT value for 4-log inactivation of HAV using ozone is 0.6 mg-min/L
at a pH of 6-9 and a temperature of 15 deg.C (US EPA, 1991a). The CT
data for ozone were obtained from a study by Roy et al., (1982). This
study obtained data for 2-log inactivation of poliovirus 1 at 5 deg.C.
The CT value for 4-log virus inactivation listed in Table III-8 is an
extrapolation of the 2-log inactivation value assuming first-order
kinetics, as well as an adjustment for inactivation at 15 deg.C. In
addition, a safety factor of three was applied to the CT values.
However, the CT value required for 4-log virus inactivation may depend
on the virus. Poliovirus 1 (Kaneko, 1989) and enteric viruses (Finch et
al., 1992) have demonstrated other CT requirements in studies; however,
it is uncertain whether or not all other experimental conditions were
the same (e.g., temperature) .
Numerous studies on viral inactivation using UV have been
conducted, with Table III-9 presenting some of the findings. According
to these studies, 4-log UV disinfection of HAV requires an IT of
between 16 mWs/cm \2\ (Battigelli et. al., 1993) and 39.4 mWs/cm\2\
(Wilson et al., 1992). IT is the UV light irradiance multiplied by the
contact time. Other studies have shown variable IT values, depending on
the virus studied (Table III-9). Harris et al. (1987) found that an IT
of 120 mWs/cm \2\ (including a safety factor of 3) was required for 4-
log inactivation of poliovirus. Unlike many of the other alternative
treatment technologies, the efficacy of UV disinfection is not
dependent on the temperature and pH.
Table III-9.--Disinfection Studies Using Ozone, Membrane Filters and UV on Viruses
--------------------------------------------------------------------------------------------------------------------------------------------------------
Studies conducted Effectiveness Additional notes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Disinfectant Virus studied Reference E & date Log removal CT Residual Comments
--------------------------------------------------------------------------------------------------------------------------------------------------------
\4\ Ozone....................... Poliovirus......... Roy et al.,1982.... 4.................. \1\ 0.6........... N safety factor = 3.
Poliovirus......... Herbold et al.,1989 4-6................ .008.............. N T = 10 deg.C.
Kaneko, 1989....... 4.................. 5................. N
enterics........... Finch et al.,1992.. 4.................. 3................. N
HAV................ Hall & Sobsey, 1993 3.9-6.0............ 0.167............. N Also MS2.
Herbold et al.,1989 4-6................ 0.22.............. N T = 10 deg.C.
Vaughn et al,1990.. 4.................. 0.40.............. N T = 4 deg.C.
MS2................ Finch et al.,1992.. 2.7-7.............. 7.2............... N T = 22 deg.C.
Finch et al.,1992.. 4.................. .013.............. N T = 22 deg.C.
RO.............................. 0.5 nm............. Jacangelo et \2\ 100% removal... 50-70% recovery... N MWCO0.5 nm.
al.,1995.
MS2................ Adham et al.,1998.. 1.4-7.4............ N/A............... N
NF.............................. 0.5-13 US EPA, 1993....... \2\ 100% removal... 60-80% recovery... N MWCO 200-400
nm. Daltons.
UV\3\ \4\...................... MS2................ Snicer et al.,1996. 4.................. 87.4-93........... N Ground water.
Roessler & Severin, 4.................. 63.... N ..................
1996.
HAV................ Wiedenmann et 4.................. 20 N ..................
al.,1993.
Battigelli et 4.................. 16................ N ..................
al.,1993.
Wilson et al.,1992. 4.................. 39.4.............. N Also Rota SA11,
Poliovirus 1.
\3\ \4\ UV continued............ Rotavirus.......... Roessler & Severin, 4.................. 25.... N ..................
1996.
Poliovirus......... Harris et al.,1987. 4.................. 120............... N Safety factor = 3.
Chang et al.,1985.. 3-4................ 30.... N ..................
Rotavirus SA11..... Battigelli et 4.................. 42................ N Approximately 4-
al.,1993. log.
Chang et al.,1985.. 3-4................ 30.... N ..................
Coxsackie B5....... Battigelli et 4.................. 29................ N Approximately 4-
al.,1993. log.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ CT values are values for 15 deg.C and a pH of 6-9, unless otherwise noted.
\2\ Removal based on pore size.
\3\ Inactivation measured by IT, rather than CT. IT is the UV irradiance multiplied by the contact time.
\4\ Table adapted from Technologies and Costs for Ground Water Disinfection (USEPA, 1993)
[[Page 30238]]
When systems use anodic oxidation the primary disinfectant
generated is free chlorine. Therefore, the CT value for anodic
oxidation is the same as free chlorine (Table III-8). However, when
using anodic oxidation other disinfectants are also generated, and data
suggests that the combined effects of these disinfectants are stronger
than that of free chlorine alone; however, this effect has not been
substantiated.
Removal as a ground water treatment technique provides public
health protection through physical filtering of water using membrane
processes. The effectiveness of a particular membrane technology
depends on the size of the target organism and the size of the
membrane's pores (Table III-9). Membrane filters achieve removals when
the MWCO of the filter is significantly smaller than the diameter of
the target organism. Viruses range in diameter from approximately 20-
900 nm and may be effectively removed using reverse osmosis (RO) and
nanofiltration (NF), having MWCOs of approximately 5 nm and 30 nm,
respectively. Those technologies which provide removal of microbial
contamination cannot provide a disinfectant residual, and must be
applied prior to the distribution of the water.
vi. Free Chlorine in the Distribution System
Chlorine disinfection is the most commonly practiced disinfection
technology for microbial contamination of ground water. Many ground
water systems which practice chlorine disinfection do so by providing a
free chlorine residual at the entry point to the distribution system.
In general, the level of inactivation achieved using disinfectants such
as chlorine increases the longer the disinfectant is in contact with
the water (i.e., contact time). This is true only when there is an
available supply of chlorine. When the chlorine dissipates there is no
further increase in the inactivation level. Therefore, when systems use
a chlorine residual at the entry point to the distribution system,
microbes (including viruses) are inactivated at varying levels through
the length of the distribution system, and the risk of illness from
pathogens originating in the source water decreases with increased
travel time through a well-maintained distribution system if there is
sufficient residual. For example, if customers at the first service
connection in the water main receive water disinfected to 4-log virus
inactivation, those customers farther along the distribution main would
receive water disinfected to levels greater than 4-logs as long as
disinfectant remains, and no additional contamination has entered the
distribution system.
EPA conducted analyses to evaluate the potential effectiveness of a
free chlorine distribution system residual to provide 4-log
inactivation of viruses originating in the source water. It was assumed
that the customer at the first service connection received water
disinfected to 4-log virus inactivation. Preliminary analysis indicates
that a number of ground water systems can achieve at least 4-log virus
inactivation throughout the distribution system. Some systems can
provide this log inactivation by maintaining a 0.2 mg/l free chlorine
residual at the entry point to the distribution system (as required by
the SWTR) and a contact time of 20 minutes prior to the first customer.
Data suggests that as many as 77% of small community ground water
systems (i.e., serving less than 10,000 customers) may achieve 4-log
virus inactivation prior to the first customer during maximum flow
conditions (AWWA, unpublished data 1998). When a ground water system
uses a free chlorine distribution system residual to disinfect
contaminated source water, the level of virus inactivation is likely
well in excess of 4-log, especially when taking into account the time
the water awaits usage in the customers' piping beyond the service
connection. This extra holding time in the distribution system
increases the CT value achieved and therefore increases the log
inactivation level achieved. A system may also need to apply a free
chlorine residual at the entry point to the distribution system that is
higher than 0.2 mg/L to maintain a detectable residual throughout the
distribution system, which may lead to higher levels of virus
inactivation. In these instances, increased levels of protection would
be provided for customers served by all service connections along the
distribution main. Assuming 4-log virus inactivation at the first
customer, it could also be assumed that customers at service
connections at later points in the distribution system would receive
water disinfected to higher levels of inactivation, in many cases much
higher.
For some systems application of a 0.2 mg/L free chlorine residual
at the entry point to the distribution system and a detectable free
chlorine residual throughout the distribution system will not achieve
4-log virus inactivation. In some cases this will be because the system
does not achieve adequate contact time, and these systems may have to
increase the contact time by installing extra distribution system
storage, increasing the free chlorine residual concentration, adding
supplemental disinfection (such as disinfection in a contact basin) or
reconfiguring the system. However, based on 1998 AWWA data, EPA
believes that most ground water CWSs will have sufficient contact time.
EPA considered requiring systems to apply a disinfectant residual
at the entry point to the distribution system and maintain a detectable
disinfectant residual throughout the distribution system. However, EPA
decided against including it in the proposed GWR since a disinfectant
residual is more accepted as a distribution system tool than for
controlling source water contamination. EPA will address the issue of
maintaining a residual in future rulemaking efforts (e.g. long term 2
ESWTR) as part of a broad discussion on distribution system issues for
all PWSs.
2. Proposed Requirements
EPA proposes the following requirements for ground water systems
with an uncorrected significant deficiency or fecally contaminated
source water. The requirements for treatment techniques, disinfection
monitoring, and notification to ensure public health protection are
addressed.
EPA proposes treatment technique requirements as one barrier in the
multiple barrier approach. Treatment techniques contribute to public
health protection by eliminating public exposure to the source of
pathogens, through eliminating the source of contamination, requiring
the system to provide an alternative source as the State deems
appropriate, correcting significant deficiencies that can act as a
potential pathway for contamination, or disinfection to remove, or
inactivate the microbial contaminants. Information related to the
effectiveness of these treatment techniques can be found in the ASDWA
BMP study Results and Analysis of ASDWA Survey of BMPs in Community
Ground Water Systems (ASDWA, 1998), as well as the SWTR.
a. Treatment Technique Requirements for Systems With Uncorrected
Significant Deficiencies or Source Water Contamination
EPA proposes requiring ground water systems with an uncorrected
significant deficiency or source water contamination to apply an
appropriate treatment technique, as determined by the State, within 90
days of detection of the significant deficiency or source water
contamination. If they cannot apply an appropriate treatment technique
within that time frame, they must at a minimum have a State-
[[Page 30239]]
approved plan and specific schedule for doing so. Treatment techniques
include: eliminate the source of contamination, correct the significant
deficiency, provide an alternate source water, or provide a treatment
which reliably achieves at least 99.99 percent (4-log) inactivation or
removal of viruses before or at the first customer. Some treatment
techniques are inappropriate solutions for the nature of the problem.
For example, a system with contamination entering the distribution
system must not address the problem by providing treatment at the
source.
Ground water systems which provide 4-log inactivation or removal of
viruses will be required to conduct compliance monitoring to
demonstrate treatment effectiveness. If a system is unable to address
the significant deficiency within 90 days, the system must develop a
specific plan and schedule for providing a treatment technique, submit
the plan and schedule to the State and receive State approval on the
plan and schedule within the same 90 days. EPA expects the system to
consult with the State on interim measures to ensure safe water is
provided during the 90 day correction time frame. During this 90 day
period the State and system must identify and apply a permanent
treatment technique appropriate for that system, consistent with the
State's general approach outlined in their primacy package. If the
treatment technique is not complete within 90 days (or the deadline
specified in the State-approved plan), the system is in violation of
the treatment technique requirements of the GWR.
b. Disinfection Options
EPA proposes requiring systems that disinfect due to uncorrected
significant deficiencies or fecally contaminated source water to
provide disinfection adequate to achieve at least 4-log inactivation or
removal of viruses as determined by the State. When a system provides
disinfection for uncorrected significant deficiencies or fecally
contaminated source water, EPA recommends that the State use EPA-
published CT tables to determine what treatment technologies and what
disinfection parameters are appropriate for the system. If a system is
currently providing 4-log disinfection and therefore does not monitor
the source water for fecal indicators, per Sec. 140.403, then that
system must meet the definition and requirements of disinfection as
described in this section.
c. Monitoring the Effectiveness and Reliability of Treatment
EPA proposes requiring systems with uncorrected significant
deficiencies or fecally contaminated source water under this proposal
to monitor the effectiveness and reliability of disinfection as
follows. This monitoring must be conducted following the last point of
treatment, but prior to each point of entry to the distribution system.
Systems serving 3,300 or more people that chemically disinfect must
monitor (using continuous monitoring equipment fitted with an alarm)
and maintain the required residual disinfectant concentration
continuously to ensure that 4-log virus inactivation is provided every
day the system serves water to the public. EPA recommends that the
State use EPA-developed CT tables to determine if the system meets the
residual concentration and contact time requirements necessary to
achieve 4-log virus inactivation. As a point of comparison, the surface
water system size cutoff for systems to measure the residual
disinfectant four or fewer times per day is 3,300 people served.
Systems serving 3,300 or fewer people that chemically disinfect
must monitor and maintain the residual disinfectant concentration every
day the system serves water to the public. The system will monitor by
taking daily grab samples and measuring for the State-determined
concentration of disinfectant to ensure that 4-log virus inactivation
is provided. EPA recommends that the State use EPA-developed CT tables
to determine if the system meets the residual concentration and contact
time requirements necessary to achieve 4-log virus inactivation. If the
daily grab measurement falls below the State-determined value, the
system must take follow-up samples every four hours until the required
residual disinfectant concentration is restored.
Systems using UV disinfection must monitor for and maintain the
State-prescribed UV irradiance level continuously to ensure that 4-log
virus inactivation is provided every day the system serves water to the
public. EPA recommends that the State use EPA-developed IT tables to
determine if the system meets the irradiance and contact time
requirements necessary to achieve 4-log virus inactivation.
Systems that use membrane filtration as a treatment technology are
assumed to achieve at least 4-log removal of viruses when the membrane
process is operated in accordance with State-specified compliance
criteria, or as provided by EPA, and the integrity of the membrane is
intact. Applicable membrane filtration technologies are RO, NF and any
membrane filters developed in the future that have MWCOs that can
achieve 4-log virus removal.
When monitoring on a continuous basis, the system must notify the
State any time the residual disinfectant concentration or irradiance
falls below the State-prescribed level and is not restored within four
hours. This notification must be made as soon as possible, but in no
case later than the end of the next business day.
When the system takes daily grab sample measurements, the system
must notify the State any time the residual disinfectant concentration
falls below the State-prescribed level and is not restored within four
hours. This notification must be made as soon as possible, but in no
case later than the end of the next business day.
Any time a system using membrane filtration as a treatment
technology fails to operate the process in accordance with State-
specified compliance criteria, or as provided by EPA, or a failure of
the membrane integrity occurs, and the compliance operation or
integrity is not restored within four hours, the system must notify the
State. This notification must be made as soon as possible, but in no
case later than the end of the next business day.
These requirements are consistent with those for surface water
systems. Four hours is the cutoff time by which a surface water system
must restore the free chlorine residual level at entry to the
distribution system to 0.2 mg/L, if the free chlorine residual at entry
to the distribution system falls below 0.2 mg/L. In addition, a surface
water system must notify the State anytime the residual disinfectant
entering the distribution system falls below 0.2 mg/L and is not
restored within 4 hours. This notification must be made by the end of
the next business day.
EPA proposes that systems which were required to provide treatment
for uncorrected significant deficiencies or fecally contaminated source
water may discontinue treatment if the State determines the need for
treatment no longer exists and documents such a decision.
d. Eliminating the Source of Contamination
For systems eliminating the source of contamination, EPA proposes
that the system and State develop a strategy using appropriate BMPs
considering the characteristics of the system and the nature of the
significant deficiency or contamination.
[[Page 30240]]
e. Reporting Outbreaks
As required in 141.32(a)(iii)(D) for undisinfected surface water
systems; EPA proposes that if any ground water system has reason to
believe that a disease outbreak is potentially attributable to their
drinking water, it must report the outbreak to the State as soon as
possible, but in no case later than the end of the next business day.
f. Treatment Technique Violations
The GWR proposes the following three treatment technique
violations, requiring the ground water system to give public
notification:
(a) A ground water system with a significant deficiency identified
by a State, which does not correct the deficiency, provide an
alternative source, or provide 4-log inactivation or removal of viruses
within 90 days, or does not obtain, within the same 90 days, State
approval of a plan and schedule for meeting the treatment technique
requirement, is in violation of the treatment technique.
(b) A ground water system that detects fecal contamination in the
source water and does not eliminate the source of contamination,
correct the significant deficiency, provide an alternate source water,
or provide a treatment which reliably achieves at least 99.99 percent
(4-log) inactivation or removal of viruses before or at the first
customer within 90 days, or does not obtain within the same 90 days,
State approval of a plan for meeting this treatment technique
requirement, is in violation of the treatment technique unless the
detected sample is invalidated by the State or the treatment technique
is waived by the State. Ground water systems which provide 4-log
inactivation or removal of viruses will be required to conduct
compliance monitoring to demonstrate treatment effectiveness.
(c) A ground water system which fails to address either a
significant deficiency as provided in (a) or fecal contamination as
provided in (b) according to the State-approved plan, or by the State-
approved deadline, is in violation of the treatment technique. In
addition, a ground water system which fails to maintain 4-log
inactivation or removal of viruses, once required, is in violation of
the treatment technique, if the failure is not corrected within four
hours.
EPA requests comment on which (if any) of these proposed treatment
technique violations should or should not be treatment technique
violations. EPA also requests comment as to whether a ground water
system which has a source water sample that is positive for E. coli,
coliphage or enterococci should be in violation of the treatment
technique.
3. Public Notification
Sections 1414(c)(1) and (c)(2) of the 1996 SDWA, as amended,
require that public water systems notify persons served when violations
of drinking water standards occur. EPA has recently (64 FR 25963, May
13, 1999) proposed to revise the public notification regulations to
incorporate new statutory provisions enacted under the 1996 SDWA
amendments. EPA recently promulgated the final Public Notification Rule
(PNR), under part 141. Subsequent EPA drinking water regulations that
affect public notification requirements will amend the PNR as a part of
each individual rulemaking. The GWR is proposing Tier 1 (discussed
next) public notification requirements for the treatment technique
violations (see Sec. 141.405). EPA requests comment on the GWR public
notification requirements.
The purpose of public notification is to alert customers to
potential risks from violations of drinking water standards and to
inform them of any steps they should take to avoid or minimize such
risks. A public water system is required to give public notice when it
fails to comply with existing drinking water regulations, has been
granted a variance or exemption from the regulations, or is facing
other situations posing a potential risk to public health. Public water
systems are required to provide such notices to all persons served by
the water system. The proposed PNR divides the public notice
requirements into three tiers, based on the seriousness of the
violation or situation.
Tier 1 is for violations and situations with significant potential
to have serious adverse effects on human health as a result of short-
term exposure. Notice is required within 24 hours of the violation.
Drinking water regulations requiring a Tier 1 notice include: Violation
of the TCR, where fecal contamination is present; nitrate violations;
chlorine dioxide violations; and other waterborne emergencies. The
State is explicitly authorized to add other violations and situations
to the Tier 1 list when necessary to protect public health from short-
term exposure.
Tier 2 is for other violations and situations with potential to
have serious adverse effects on human health. Notice is required within
30 days, with extension up to three months at the discretion of the
State or primacy agency. Violations requiring a Tier 2 notice include
all other MCL and treatment technique violations and specific
monitoring violations when determined by the State.
Tier 3 is for all other violations and situations requiring a
public notice not included in Tier 1 and Tier 2. Notice is required
within 12 months of the violation, and may be included in the Consumer
Confidence Report at the option of the water system. Violations
requiring a Tier 3 notice are principally the monitoring violations.
Today's regulatory action proposes to make the presence of a fecal
indicator in a source water sample, failure to monitor source water and
treatment technique violations as Tier 1 public notification
requirements. Any GWSs with a violation or situation requiring Tier 1
public notification must notify the public within 24 hours of the
violation. GWS's that must make an annual CCR report, as discussed in
III.A.7.d., must include any Tier 1 violations or situations in their
next CCR report and include the health effects language described later
in Appendix B of subpart Q. The following violations or situations
require Tier 1 notice:
(a) A ground water system which has a source water sample that is
positive for E. coli, coliphage, or enterococci under Sec. 141.403,
unless it is invalidated under Sec. 141.403(i);
(b) Failure to conduct required monitoring, including triggered
monitoring when a system has a positive total coliform sample in the
distribution system and routine monitoring when the system is
identified by the State as hydrogeologically sensitive;
(c) A ground water system with a significant deficiency identified
by a State which does not correct the deficiency, provide an
alternative source, or provide 4-log inactivation or removal of viruses
within 90 days, or does not obtain, within the same 90 days, State
approval of a plan and schedule for meeting the treatment technique
requirement in Sec. 141.404;
(d) A ground water system that detects fecal contamination in the
source water and does not eliminate the source of contamination,
provide an alternative water source, or provide 4-log inactivation or
removal of viruses within 90 days, or does not obtain within the same
90 days, State approval of a plan for meeting this treatment technique
requirement (unless the detected sample is invalidated under
Sec. 141.403(i) or the treatment technique is waived under
Sec. 141.403(j)); and
(e) A ground water system which fails to address either a
significant deficiency as provided in (c) or fecal contamination as
provided in (d) according to the
[[Page 30241]]
State-approved plan, or by the State-approved deadline. (In addition, a
ground water system which fails to maintain 4-log inactivation or
removal of viruses, once required, is in violation of the treatment
technique if the failure is not corrected within 4 hours.)
EPA believes that these violations pose an immediate and serious
public health threat. Fecal contamination is an acute contaminant and
therefore illnesses and even deaths can occur through small volumes or
short exposure to fecally contaminated drinking water. Illnesses can be
avoided by alerting the public immediately. The proposed tiering
requirements under the GWR are designed to be consistent with those for
the Total Coliform Rule. Failure to test for fecal coliform or E. coli
when any repeat sample tests positive for coliform is considered a Tier
1 violation requiring a Tier 1 notice under current Public Notification
Regulations. EPA believes that failure to collect source water samples
as proposed under the GWR poses an equivalent public health threat to
the failure to test for fecal coliform or E. coli under the TCR. EPA
believes that an undisinfected ground water system with either a TC
positive in the distribution system or with a source found to be
hydrogeologically sensitive has an increased likelihood of microbial
contamination that if not monitored, presents a public health threat
which requires immediate notice. EPA acknowledges that in some
circumstances, the hydrogeologic sensitivity assessment may not be as
indicative of the presence of microbial contamination in the ground
water system as is the presence of total coliform in the distribution
system. Given this potential situation, the Agency requests comment
upon whether the failure to perform routine source water monitoring
should be considered a lower Tier violation to avoid alarming the
public unnecessarily. EPA also requests comment on the other proposed
public notification requirements presented in this section.
4. Request for Comments
EPA requests comments on all the information presented earlier and
the potential impacts on public health and regulatory provisions of the
GWR. In addition, EPA specifically requests comments on the following
alternative approaches. In particular, EPA requests comment on the
following public health issues associated with disinfection.
Stakeholders have raised concern about the potential risk from
improperly managed or applied chemical disinfectants. Some stakeholders
suggest that requiring small system operators who may lack training or
expertise to apply chemical disinfection could lead to collateral
health and safety risks. EPA requests comment on this issue. The Agency
also requests input on alternative approaches for addressing
demonstrated microbial contamination and the associated acute microbial
health risks.
Alternative Approaches
a. Distribution System Residuals
EPA requests comment on requiring a 0.2 mg/L free chlorine residual
at the entry points to the distribution system and a detectable free
chlorine residual throughout the distribution system for all or some
systems (e.g., all systems serving 3,300 or more people). EPA also
seeks comment on whether or not systems should be able to use a 0.2 mg/
L free chlorine residual at the entry to, and detectable throughout,
the distribution system to meet the disinfection requirements proposed
as part of the GWR.
b. Other Log-Inactivation Levels
EPA seeks comment on the adequacy of 4-log virus inactivation or
removal to protect public health from fecally contaminated ground water
sources. Additionally, EPA requests comment on requiring additional
levels of disinfection under certain circumstances. For example,
increasing the log virus inactivation may be appropriate for
contaminated systems with known sources of fecal contamination in close
proximity to a well.
c. Supplemental Disinfection Strategies
EPA requests comment on whether, for certain systems with source
water contamination, it may not be possible to achieve 4-log virus
inactivation at the first customer either because of the distribution
system size or configuration (e.g., the first customer is relatively
close to the point of disinfectant application). EPA requests comment
on possible supplemental disinfection strategies.
d. Mandatory Disinfection for Systems in Sensitive Hydrogeology
EPA seeks comment on requiring disinfection for ground water
systems which obtain their water from a sensitive aquifer regardless of
microbial monitoring results (see section III.B.). This would provide
proactive public health protection by disinfecting a sensitive source
water before contamination becomes apparent.
e. Point-of-Entry Devices
EPA seeks comment on EPA approving the use of point-of-entry
devices to disinfect contaminated source water. This would allow
systems to provide protection to individual households, and may be
cost-effective for some very small systems. However, the system would
be responsible for maintaining the devices and this could result in
significant expenditure of resources.
f. Across-the-Board Disinfection
EPA seeks comment on requiring all systems to disinfect, or
requiring disinfection based on system type (e.g., CWS), or size of the
system (e.g., greater than 3,300). The SWTR requires all systems
obtaining their water from a surface water source to disinfect. EPA
notes that 1996 SDWA, as amended requires that EPA should develop
regulations requiring disinfection for ground water systems ``as
necessary''.
g. Health and Fiscal Impacts on Small Systems (i.e., Competing
Priorities)
EPA requests comment on whether or not potential health effects and
fiscal impacts specific for small systems should be included in the
GWR. Specifically, EPA seeks comment on what other regulatory
priorities will compete with the GWR and what implementation issues
this will present (e.g., disinfection under the GWR versus compliance
with the DBPR, difficulty in obtaining resources for simultaneous
compliance with arsenic, radon, ground water and DBP regulations).
h. Differing Disinfection Strategies for Significant Deficiencies and
Source Water Contamination
EPA seeks comment on whether a different disinfection strategy
should be required depending on whether the system has an uncorrected
significant deficiencies or fecally contaminated source water. Under
this alternative, EPA could require systems with uncorrected
significant deficiencies to provide only a disinfectant residual of 0.2
mg/L free chlorine at entry to the distribution system, while those
systems with fecally contaminated source water would be required to
provide disinfection to ensure that the system achieves 4-log virus
inactivation or removal prior to entry to the distribution system.
i. Shutting Down Systems With Uncorrected Significant Deficiencies
EPA seeks comment on whether and based on what criteria systems
with uncorrected significant deficiencies should not be allowed to
disinfect as a
[[Page 30242]]
treatment technique, but instead would not be allowed to serve water to
the public. Under certain circumstances this approach is used by some
States. For example, disinfection is not an effective strategy for
treating the significant deficiency of poor distribution system
integrity.
j. Correction Time Frame
EPA requests comment on the criteria States must use to determine
the adequacy of schedules which go beyond 90 days (e.g., corrections
which require significant capital investments or external technical
expertise).
EPA also requests comment on an alternative approach for addressing
correction of significant deficiencies. The alternate approach consists
of: (1) A requirement that the State notify the system in writing
within 30 days of conducting the sanitary survey listing the
significant deficiency, (2) a requirement for the system to correct the
significant deficiencies as soon as possible, but no later than 180
days of receipt of the letter from the State or in compliance with a
schedule of any length agreed upon by the State, and (3) the
requirement that the system notify the State in writing that the
significant deficiencies have been corrected within 10 days after the
date of completion. Under this alternative, a system that does not
correct significant deficiencies within 180 days or within the time
frames of a schedule agreed upon by the State is in violation of a
treatment technique and must provide public notice. The Agency seeks
comment on whether this particular alternative correction scheme would
be appropriate for the purposes of this rule.
The Agency is also seeking comment on a second alternative approach
for establishing deadlines to complete corrective actions of
significant deficiencies. Under this approach, States, as part of their
primacy requirement to identify and define the significant
deficiencies, may develop and submit to EPA for approval, deadlines for
the completion of corrective actions for specific types or categories
of significant deficiencies. When a specific corrective action is not
implemented within the State deadline, a State must take appropriate
action to ensure that the system meets the corrective action
requirement. Any corrective action that extends beyond 180 days to
complete, must be enforceable by the State through a compliance
agreement or an administrative order or judicial order. As part of
primacy, the State must also provide a plan for how the State will meet
the time frames established in their procedures for identifying,
reporting, correcting, and certifying significant deficiencies within
the 180 days. The Agency seeks comment on whether this alternative
correction scheme might also be appropriate.
k. Required Disinfectant Residual Concentration
EPA requests comment on requiring systems that disinfect to
maintain a specified default disinfectant residual level. This
requirement would apply when the State fails to provide the system with
a State-determined disinfectant concentration to meet the 4-log
inactivation/removal requirement within the 90-day correction time
frame. Under this approach, systems that must treat would be required
to maintain a 0.2 mg/L free chlorine residual at entry to the
distribution system and a detectable free chlorine residual throughout
the distribution system. EPA also requests comment on other
concentrations of residual free chlorine to be maintained both at entry
to the distribution system and throughout the distribution system
(e.g., 0.5 mg/L free chlorine at entry to the distribution system and
0.2 mg/L free chlorine throughout the distribution system).
l. Record Keeping for 4-log Inactivation Requirements
EPA requests comment upon whether systems which disinfect to comply
with the GWR must maintain records of the State notification of the
proper residual concentrations (when using chemical disinfection),
irradiance level (when using UV), or State-specified compliance
criteria (when using membrane filtrations) needed to achieve 4-log
inactivation or removal of virus. EPA also requests comment on systems
keeping records of the level of disinfectant residuals maintained, as
well as how long the system should keep the records (e.g., three
years). These records may be valuable in the operation of the system
because they will serve as permanent records for subsequent operators
and/or owners of the ground water system.
m. Differing Monitoring Requirements for Consecutive Systems
EPA requests comment on any GWR requirements that should not apply
to consecutive systems. Consecutive systems are those PWSs that receive
some or all of their water from other PWSs. Such systems would
certainly need to undergo the proposed sanitary survey to assure that
they are delivering safe water to their customers. EPA also requests
comment on whether the hydrogeologic sensitivity assessment and any
corresponding source water monitoring should be the responsibility of
the water seller or the consecutive system. EPA requests comments on
whether or not a consecutive system should be required to monitor
treatment compliance in their distribution system if the seller has met
4-log inactivation or removal of viruses. In addition, EPA requests
comment on the selling system being required to conduct triggered
source water monitoring when the consecutive system has a total-
coliform positive in the distribution system.
n. State Primacy Requirements
EPA requests comment on the scope and appropriateness of the GWR
State primacy requirements. The primacy requirements include the
following:
Sanitary surveys: State will describe how it will
implement the sanitary survey, including rationales and time frames for
phasing in sanitary surveys, how it will decide that a CWS has
outstanding performance, and how the State will utilize data from its
SWAPP;
Hydrogeologic Sensitivity Assessment: State will identify
its approach to determining the adequacy of a hydrogeologic barrier, if
present;
Source Water Monitoring: State will describe its approach
and rationale for determining which of the fecal indicators (E. Coli,
coliphage or enterococci) ground water systems must use for routine
and/or triggered monitoring;
Treatment Techniques: State will describe treatment
techniques, including how it will provide systems with the disinfectant
concentration (or irradiance) and contact time required to achieve 4-
log virus inactivation; the approach the State must use to determine
which specific treatment option (correcting the deficiency, eliminating
the source of contamination, providing an alternative source, or
providing 4-log inactivation or removal of viruses) is appropriate for
addressing significant deficiencies or fecally contaminated source
water and under what circumstances; and how the State will consult with
ground water systems regarding the treatment technique requirements.
o. State Reporting Requirements
The proposed rule contains many reporting requirements for States
to submit to EPA. EPA requests comment on the scope and appropriateness
of these reporting requirements. The GWR reporting requirements include
the following:
Sanitary Survey: State will report an annual list of
ground water systems that have had a sanitary survey
[[Page 30243]]
completed during the previous year and an annual evaluation of the
State's program for conducting sanitary surveys.
Hydrogeologic Sensitivity Assessment: State will report
lists of ground water systems that have had a sensitivity assessment
completed during the previous year, those ground water systems which
are sensitive, ground water systems which are sensitive, but for which
the State has determined that a hydrogeologic barrier exists, and an
annual evaluation of the State's program for conducting hydrogeologic
sensitivity assessments.
Source Water Monitoring: State will report an annual list
of ground water systems that have had to test the source water, a list
of determinations of invalid samples, and a list of waivers of source
water monitoring provided by the State.
Treatment Techniques: State will report lists of ground
water systems that have had to meet treatment technique requirements
for significant deficiencies or contaminated source water,
determinations to discontinue 4-log inactivation or removal of viruses,
ground water systems that violated the treatment technique
requirements, and an annual list of ground water systems that have
notified the State that they are currently providing 4-log inactivation
or removal of viruses.
IV. Implementation
This section describes the regulations and other procedures and
policies States have to adopt, and the requirements that public ground
water systems would have to meet to implement today's proposal were it
to be finalized as proposed. Also discussed are the compliance
deadlines for these requirements. States must continue to meet all
other conditions of primacy in Part 142 and ground water systems must
continue to meet all other applicable requirements of Part 141.
Section 1413 of the SDWA establishes requirements that a State or
eligible Indian Tribe must meet to maintain primary enforcement
responsibility (primacy) for its public water systems. These include
(1) adopting drinking water regulations that are no less stringent than
Federal NPDWRs in effect under sections 1412(a) and 1412(b) of the Act,
(2) adopting and implementing adequate procedures for enforcement, (3)
keeping records and making reports available on activities that EPA
requires by regulation, (4) issuing variances and exemptions (if
allowed by the State) under conditions no less stringent than allowed
by sections 1415 and 1416, and (5) adopting and being capable of
implementing an adequate plan for the provision of safe drinking water
under emergency situations.
40 CFR part 142 sets out the specific program implementation
requirements for States to obtain primacy for the Public Water Supply
Supervision (PWSS) Program, as authorized under section 1413 of the
Act. In addition to adopting the basic primacy requirements, States may
be required to adopt special primacy provisions pertaining to a
specific regulation. These regulation-specific provisions may be
necessary where implementation of the NPDWR involves activities beyond
those in the generic rule. States are required by 40 CFR 142.12 to
include these regulation-specific provisions in an application for
approval of their program revisions. These State primacy requirements
apply to today's proposed rule, along with the special primacy
requirements discussed next. The proposed regulatory language under
section 142 applies to the States. The proposed regulatory language in
section 141 applies to the public water systems.
The 1996 SDWA amendments (see section 1412(b)(10)) provide 3 years
after promulgation for compliance with new regulatory requirements.
Accordingly, the GWR requirements that apply to the PWS directly,
specifically requirements found under section 141 of this proposal
(monitoring and corrective action), are effective three years after the
promulgation date. The State may, in the case of an individual system,
provide additional time of up to two years if necessary, for capital
improvements in accordance with the statute.
Section 1413(a)(1) allows States two years after promulgation of
the final GWR to adopt drinking water regulations that are no less
stringent than the final GWR. EPA proposes to require States to submit
their primacy application concerning the GWR (see section 142 of the
proposed regulatory language) within two years of the promulgation of
the final GWR and EPA will review and approve (if appropriate) the
application within 90 days of submittal (1413(b)(2). This schedule will
provide all States with approved primacy for the GWR by the three years
after [DATE OF PUBLICATION OF THE FINAL RULE IN THE FEDERAL REGISTER].
If the GWR is finalized as proposed today, the States will have
three years from the effective date (six years from the GWR
promulgation date) to complete all community water system sanitary
surveys and five years from the effective date (eight years from the
GWR promulgation date) to complete all non-community water system
sanitary surveys. The monitoring and corrective action requirements
would be effective on the effective date of the final rule (three years
after the GWR promulgation date).
V. Economic Analysis (Health Risk Reduction and Cost Analysis)
This section summarizes the Health Risk Reduction and Cost Analysis
in support of the GWR as required by section 1412(b)(3)(C) of the 1996
SDWA. In addition, under Executive Order 12866, Regulatory Planning and
Review, EPA must estimate the costs and benefits of the GWR in a
Regulatory Impact Analysis (RIA) and submit the analysis to the Office
of Management and Budget (OMB) in conjunction with publishing the
proposed rule. EPA has prepared an RIA to comply with the requirements
of this Order and the SDWA Health Risk Reduction and Cost Analysis
(USEPA, 1999a). The RIA has been published on the Agency's web site,
and can be found at http://www.epa.gov/safewater. The RIA can also be
found in the docket for this rulemaking (US EPA, 1999a).
The goal of the following section is to provide an analysis of the
costs, benefits, and other impacts to support decision making during
the development of the GWR.
A. Overview
The analysis conducted for this rule quantifies cost and benefits
for four scenarios; the proposed regulatory option (multi-barrier
option), the sanitary survey option, the sanitary survey and triggered
monitoring option, and the across-the-board disinfection option. All
options include the sanitary survey provision. The sanitary survey
option would require the primacy agent to perform surveys every three
to five years, depending on the type of system. If any significant
deficiency is identified, a system is required to correct it. The
sanitary survey and triggered monitoring option adds a source water
fecal indicator monitoring requirement triggered by a total coliform
positive sample in the distribution system. The multi-barrier option
adds a hydrogeologic sensitivity assessment to these elements which, if
a system is found to be sensitive, results in a routine source water
fecal indicator monitoring requirement. The multi-barrier option and
the sanitary survey and triggered monitoring options are both a
targeted regulatory approach designed to identify wells that are
fecally contaminated or are at a high risk for contamination. The
across-the-board disinfection option would require all systems to
install treatment instead
[[Page 30244]]
of trying to identify only the high risk systems; therefore, it has no
requirement for sensitivity assessment or microbial monitoring.
Costs for each option varied and were driven by the number of
systems that would need to fix a significant deficiency or take
corrective action, such as installing treatment or rehabilitating a
well, in response to fecal contamination. The majority of costs for all
options, with the exception of the across-the-board option, are the
result of systems having to fix an actual or potential fecal
contamination problem. The mean annual costs of the various options
range from $73 million to $777 million using a three percent discount
rate and $76 million to $866 million using a seven percent discount
rate. (Note some costs have not been quantified and are not included in
these totals, see section V.B.)
These total annual quantified costs can be compared to the annual
monetized benefits of the GWR. The annual mean benefits of the various
rule options range from $33 million to $283 million. This result is
based on the quantification of the number of acute viral illnesses and
deaths avoided attributable to this rule. This rule will also decrease
bacterial illness and death associated with fecal contamination of
ground water. EPA did not directly calculate the actual numbers of
illness associated with bacterially contaminated ground water because
the Agency lacked the necessary bacterial pathogen occurrence data
(e.g., number of wells contaminated with Salmonella) to include it in
the risk model. However, in order to monetize the benefit from reduced
bacterial illnesses and deaths from fecally contaminated ground water,
the Agency used the ratio of viral and unknown etiology outbreak
illnesses to bacterial outbreak illnesses reported to CDC for
waterborne outbreaks in ground water systems.
Several non-health benefits from this rule were also considered by
EPA but were not monetized. The non-health benefits of this rule
include avoided outbreak response costs (such as the costs of providing
public health warnings and boiling drinking water), and possibly the
avoided costs of averting behavior and reduced uncertainty about
drinking water quality. There are also non-monetized disbenefits, such
as increased exposure to DBPs.
Additional analysis was conducted by EPA to look at the incremental
impacts of the various rule options, impacts on households, benefits
from reduction in co-occurring contaminants, and increases in risk from
other contaminants. Finally, the Agency evaluated the uncertainty
regarding the risk, benefits, and cost estimates.
B. Quantifiable and Non-Quantifiable Costs
In estimating the cost of each rule option, the Agency considered
impacts on public water systems and on States. The GWR will result in
increased costs to some PWSs for monitoring, corrective action of
significant deficiencies, and installing treatment, but these vary
depending on the option. With all rule options, a greater portion of
the regulatory burden will be placed on those systems that do not
currently disinfect to a 4-log inactivation of virus. States will incur
costs for an incremental increase in sanitary survey requirements, for
conducting hydrogeologic sensitivity assessments, and for follow-up
inspections. Both systems and States would incur implementation costs.
Some costs of today's rule options were not quantified (such as land
acquisition, public notification costs and corrections to all potential
significant deficiencies (See section V. B.4.)).
1. Total Annual Costs
In order to calculate the national costs of compliance, the Agency
used a Monte-Carlo simulation model specifically developed for the GWR.
The main advantage of this modeling approach is that, in addition to
providing average compliance costs, it also estimates the range of
costs within each PWS size and category. It also allowed the Agency to
capture the variability in PWS configuration, current treatment in
place and source water quality.
Table V-1 shows the estimated mean and range of annual costs for
each rule option. At both a three and seven percent discount rate for
the first three options, the costs increase as more components are
added for identifying fecally contaminated wells and wells vulnerable
to fecal contamination. The fourth option of across-the-board
disinfection is the most costly because it would require all systems to
install treatment regardless of actual fecal contamination or the
potential to become fecally contaminated. Costs for the States to
implement these rule options are also included in the four cost
estimates. Discount rates of three and seven percent were used to
calculate the annualized value for the national compliance cost
estimate. The seven percent rate represents the standard discount rate
required by OMB for benefit-cost analyses of government programs and
regulations.
Table V-1.--Annual Costs of Rule Options ($Million)
------------------------------------------------------------------------
3% Discount 7% Discount
Option rate $million rate $million
mean [range] mean [range]
------------------------------------------------------------------------
Sanitary Survey......................... $73 $76
[$71-$74] [$74-78]
Sanitary Survey and Triggered Monitoring $158 $169
[$153-$162] [$163-174]
Multi-barrier (Proposed) Option......... $183 $199
[$177-188] [$192-206]
Across-the-Board Disinfection........... $777 $866
[$744-$810] [$823-$909]
------------------------------------------------------------------------
2. System Costs
In order to calculate the cost impact of each rule option on public
water systems, EPA had to estimate the current baseline of systems and
their current treatment practices, and then estimate how many systems
would be affected by the various option requirements based on national
occurrence information. The industry baseline discussion is located in
section I.C. of this preamble. Estimates of the cost compliance
requirements for each rule option are captured in a decision
[[Page 30245]]
tree analysis. The decision tree is comprised of various percentage
estimates of the number of systems that will fall into each regulatory
component category. Rule components include corrective action costs or
costs to address significant deficiencies, monitoring costs, start-up
costs, and reporting costs. Each of the rule options contains various
combinations of these rule components with the sanitary survey option
containing the fewest requirements.
Overall, these rule options provide a great amount of flexibility,
with the exception of across-the-board disinfection, and this has
complicated the cost analysis. Data were not always available to
estimate the number of systems that would fall under the various rule
components. EPA used data, where available but also consulted with
experts and stakeholders to get the best possible estimates of the cost
of this rule. More information on the GWR decision tree and how each
element was estimated can be found in the Appendix to the GWR RIA (US
EPA, 1999a).
As previously mentioned, the main cost component of the first three
rule options results from systems having to take corrective action in
response to fecal contamination or to fix significant deficiencies that
could result in well contamination. In order to analyze the different
rule options, the Agency had to distinguish between correction of
significant deficiencies and the corrective actions that result from a
confirmed source water positive sample for E. coli, enterococci or
coliphage. In addition, it would be extremely challenging to cost out
all conceivable corrective actions or significant deficiencies that a
system could potentially encounter. As a result, the Agency focused on
a representative estimate of potential types of corrective actions and
significant deficiencies as shown in Table V-2 and Table V-3,
respectively.
The choice of treatment technique (in consultation with the State)
is also influenced by the size of the system. This is captured in the
decision tree analysis by assigning probabilities (by system size) that
a certain corrective action will be chosen. These probabilities are
based on the relative cost of each action, data on existing
disinfection practices, and best professional judgment. Additional
significant deficiencies related to improper treatment were included in
the cost analysis for systems that currently disinfect. These
deficiencies are also captured in the decision tree and are listed in
Table V-3.
Table V-2.--Treatment Techniques To Address Positive Source Water
Samples
------------------------------------------------------------------------
Corrective action: \1\
-------------------------------------------------------------------------
Rehabilitating an existing well
Drilling a new well
Purchasing water (consolidation)
Eliminating known sources of contamination
Installing disinfection (8 choices of technologies)
------------------------------------------------------------------------
\1\ Choice varies with systems size and corrective action feasibility.
Each treatment technique can be addressed by various low or high
cost alternatives. For example, a lower cost fix for many systems would
be to rehabilitate a well while a higher cost fix would be to drill a
new well. It is possible that not all States, in coordination with
systems, would choose the relatively lower cost alternative of well
rehabilitation. It would depend on the well itself and also the problem
that was being addressed. In addition, if the model predicted that a
system would install treatment, the choice of treatment is contingent
on system size. To capture these alternative possibilities, the Agency
considered different combinations of low and high cost alternatives.
For instance, when the low cost corrective action alternative was run,
the model estimated a greater percentage of systems choosing the lower
cost well rehabilitation option versus the higher cost option of
drilling a new well. To account for the uncertainty in the types of
significant deficiencies identified and in the treatment technique
taken, the cost model was run for each of the following combinations of
low and high costs alternatives.
Low significant deficiency cost/low treatment technique
cost
Low significant deficiency cost/high treatment technique
cost
High significant deficiency cost/low treatment technique
cost
High significant deficiency cost/high treatment technique
cost
These combinations of low and high cost are reflected in the range
of cost estimates shown in Table V-1 for the multi-barrier option
(proposed option), the sanitary survey and triggered monitoring option,
and the across-the-board option. For the sanitary survey option, only
the high and low costs associated with significant deficiencies were
included in the analysis. As stated earlier, treatment technique costs
are the result of source water monitoring which is not included with
the sanitary survey option.
Table V-3.--Significant Deficiencies
------------------------------------------------------------------------
Significant deficiencies
-------------------------------------------------------------------------
Unsealed well or inadequate well seal
Improper well construction
Inadequate roofing on a finished water storage tank
Evidence of vandalism at finished water storage tank
Unprotected cross connection in the distribution system
Booster pump station which lacks duplicate pumps
Additional significant deficiencies for disinfecting systems:
Inadequate disinfection contact time
Inadequate application of treatment chemicals
------------------------------------------------------------------------
In addition to the treatment technique costs, EPA estimated the
cost to systems for monitoring. All options would have some monitoring
costs. However, the monitoring costs vary depending on the rule option
as indicated in Table V-4. Regardless of the option, the triggered and
routine monitoring applies only to systems that do not disinfect to a
4-log inactivation of virus.
Both the triggered and routine monitoring costs are calculated
based on the cost of the test and the operator's time to take and
transport the sample. EPA assumed that if this source water sample is
positive, all systems would take five repeat samples to confirm the
positive (although this is an optional rule component). For routine
monitoring, the Agency assumed that all systems would monitor their
source water monthly for the first year and quarterly thereafter at the
States' determination. However, in some cases the State may allow the
system to discontinue monitoring after 12 monthly samples or it could
also require the system to continue with monthly monitoring. The cost
of disinfectant compliance monitoring varies with system size and would
be required for any system that currently disinfects or installs
treatment as a result of the GWR. For large systems, EPA assumed that
an automated monitoring system would be installed; for smaller systems,
EPA assumed that a daily grab sample would be taken. A more detailed
explanation of each of these monitoring schemes is located in section
III. D. and section III E.2.c.
[[Page 30246]]
Table V-4.--Monitoring Requirements by Rule Option
------------------------------------------------------------------------
Disinfectant
Option Triggered Routine compliance
monitoring monitoring monitoring
------------------------------------------------------------------------
Sanitary Survey...................
Sanitary Survey and Triggered
Monitoring Option................
Multi-barrier (Proposed) Option...
Across-the Board Disinfection
Option...........................
------------------------------------------------------------------------
Finally, the Agency accounted for a system's start-up costs to
comply with the GWR . These costs include time to read and understand
the rule, mobilization and planning, and training. EPA assumed start-up
costs would remain constant across the rule options. The Agency also
estimated system costs for reporting and recordkeeping of any positive
source water samples.
3. State Costs
Similar to the system cost, State costs also vary by rule option.
Depending on the option, States would face increased costs from the
incremental difference in the sanitary survey requirements and
frequency, from conducting a one-time hydrogeologic sensitivity
assessments, and tracking monitoring information for those options with
a monitoring requirement. States would also have start-up and annual
costs for data management and training. If a system needs longer than
90 days to complete a treatment technique or repair a significant
deficiency, the State would have to approve the time schedule and plan.
By including start-up costs, annual fixed costs, and incremental
sanitary survey costs in the decision tree analysis for all rule
options, EPA accounted for these State costs. The analysis also assumed
costs for State review and approval of plans for treatment techniques.
The cost for the one-time sensitivity assessments is included for the
proposed rule option analysis.
4. Non-Quantifiable Costs
Although EPA has estimated the cost of all the rule's components on
drinking water systems and States, there are some costs that the Agency
did not quantify. These non-quantifiable costs result from
uncertainties surrounding rule assumptions and from modeling
assumptions. For example, EPA did not estimate a cost for systems to
acquire land if they needed to build a treatment facility or drill a
new well. This was not considered because many systems will be able to
construct new wells or treatment facilities on land already owned by
the utility. In addition, if the cost of land was prohibitive, a system
may chose another lower cost alternative such as connecting to another
source. A cost for systems choosing this alternative is quantified in
the analysis. The cost estimates do not include costs for public
notification which are proposed. These estimates have not been included
because EPA has no data on which to base an estimate of the number of
treatment techniques violations or the number of times systems will
fail to perform source water monitoring.
In addition, the Agency did not develop costs for all conceivable
significant deficiencies or corrective actions that a system may
encounter. Instead, a representative sample was chosen as shown in
Tables V-2 and V-3.
C. Quantifiable and Non-Quantifiable Health and Non-Health Related
Benefits
The primary benefits of today's proposed rule come from reductions
in the risks of microbial illness from drinking water. In particular,
the GWR focuses on reducing illness and death associated with viral
infection. Exposure to waterborne bacterial pathogens are also reduced
by this rule and the benefits are monetized, but not by the same method
used to calculate reductions in viral illness and death because of data
limitations. It is likely that these monetized illness calculations
which are based on a cost of illness (COI) rather than a willingness to
pay (WTP) approach, underestimate the true benefit because they do not
include pain and suffering associated with viral and bacterial illness.
Additional health benefits such as reduced chronic illness were
investigated, but were not quantified or monetized in this analysis.
Other non-health benefits will likely result from this rule but were
also not quantified or monetized. These non-health related benefits are
discussed in sections V.A. and V.C. 2.
1. Quantifiable Health Benefits
The benefits analysis focused on estimating reductions in viral and
bacterial illness and death that would result from each of the rule
options. The first part of the analysis estimates the baseline (pre-
GWR) level of illness as a result of microbial contamination of ground
water. A discussion about how the Agency estimated this baseline risk
is located in section II. E. of today's proposal. An important
component of these risk estimates is the effect that these pathogens
have on children (especially infants) because they are more likely to
have severe illness and die from viral infection than the general
population. A detailed discussion of risks to children is located in
section VI. G.
The second part of the analysis focused on the reduction in risk
that results from the various rule components. These components include
identifying high risk wells, fixing significant deficiencies, increased
monitoring for some systems, and possibly installing treatment in the
event that a problem can not be fixed or a new source found. To
calculate these changes, the risk-assessment model was re-run using new
assumptions based on reductions in viral exposure which results from
different levels of fecal contamination identified by each rule option.
To model the reduction in source contamination that would result
from implementation of the four regulatory options, EPA assumed
reductions in the number of ground water systems/points of entry that
are potentially contaminated with viral pathogens under baseline
conditions. The reduction varies with expectations regarding the
effectiveness of each option in identifying and correcting significant
defects at the source. Reductions in treatment failure rate and in
distribution system contamination are also addressed for each option.
The estimated reductions in contamination which are expected for each
rule option are summarized in Table V-4a. These estimates are based
upon information from consultations by the Agency with stakeholders and
the Agency's best professional judgement regarding the effectiveness of
sanitary surveys and upon co-occurrence rates of fecal indicators with
pathogenic viruses. See section 5.3 of the GWR RIA for a detailed
discussion of the basis for the estimated reductions.
[[Page 30247]]
Table V-4a. Estimated Contamination Reductions for GWR Options
[In Percent]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Estimated reduction in viral source contamination of Estimated reduction in rate Estimated reduction in
undisinfected ground water sources of disinfection failure for distribution system
Regulatory option ------------------------------------------------------------ GWSs with viral contamination with virus of
Properly constructed Improperly constructed contamination of the source GWSs
--------------------------------------------------------------------------------------------------------------------------------------------------------
Option 1. Sanitary Survey Only.. 0 40-60 0-26 (CWS) 0-25
0-43 (NCWS)\1\ (NA for TNC) \2\
Option 2. Sanitary Survey and 30-54 58-82 77-100 0-25
Triggered Monitoring. (NA for TNC) \2\
Option 3. Multi-Barrier 38-77 63-91 77-100 0-25
(Proposed). (NA for TNC) \2\
Option 4. Across-the-Board 100 100 77-100 0-25
Disinfection. (NA for TNC) \2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Non-community water systems (NCWS), both transient and nontransient, have an estimated reduced risk of contamination of 0-43%; community water
systems (CWS) reduced risk is 0-26%.
\2\ Reduction of risk in transient non-community (TNC) systems was not considered.
After the reductions in viral illnesses and death were estimated,
the Agency estimated the monetized benefit from the reduction in
bacterial illnesses and death associated with each rule option. EPA
could not directly calculate the actual numbers of illnesses and death
associated with bacterially contaminated ground water because the
Agency lacked the necessary pathogen occurrence information to include
it in the risk model. In order to estimate the benefit from reducing
bacterial illnesses and deaths from fecally contaminated ground water,
the Agency relied on CDC's outbreak data ratio of viral outbreaks and
outbreaks of unknown etiology believed to be viral to bacterial
outbreaks in ground water. These data indicate that for every five
viral outbreaks, there is one bacterial outbreak. It was further
assumed that the cost of these bacterial illnesses would be comparable
to viral illness estimates.
To assign a monetary value to the illness, EPA estimated costs-of-
illness ranging from $158 to $19,711 depending upon the age of the
individual and severity of illness (see Exhibits 5-9 and 5-10 in the
RIA). These are considered lower-bound estimates of actual benefits
because it does not include the pain and discomfort associated with the
illness. This issue is discussed in greater detail in the GWR RIA
(USEPA, 1999a). Mortalities were valued using a value of statistical
life estimate (VSL) of $6.3 million consistent with EPA policy. The VSL
estimate is based on a best-fit distribution of 26 VSL studies and this
distribution has a mean of $4.8 million per life in 1990 dollars. For
this analysis, EPA updated this number to 1999 dollars which results in
a mean VSL value of $6.3 million. Table V-5 shows the annual monetized
benefits by rule option.
Table V-5.--Quantified and Monetized Benefits by Rule Option ($Million)
----------------------------------------------------------------------------------------------------------------
Morbidity Mortality Total $million
Options $million [range] $million [range] [range]
----------------------------------------------------------------------------------------------------------------
Sanitary Survey..................................... $22 $11 $33
[$7 to $38] [$2 to $20] [$9 to $58]
Sanitary Survey and Triggered Monitoring............ $120 $58 $178
[$100 to $140] [$47 to $68] [$147 to $209]
Multi-Barrier Proposed ( Option).................... $139 $66 $205
[$115 to $163] [$54 to $79] [$169 to $242]
Across-the-Board Disinfection....................... $192 $91 $283
[$174 to $210] [$81 to $101] [$255 to $311]
----------------------------------------------------------------------------------------------------------------
2. Non-Quantifiable Health and Non-Health Related Benefits
Although viral and some bacterial illness have been linked to
chronic diseases, insufficient data was available to forecast the
number of avoided chronic cases that would result from each rule
option. A review of medical and epidemiological data identified several
chronic diseases linked to viral infections. The strongest evidence
links Group B coxsackievirus infections with Type 1-insulin-dependent
diabetes and also to heart disease. Bacterial illness can also result
in longer-term complications including arthritis, recurrent colitis,
and hemolytic uremic syndrome. Most of these chronic illnesses and
longer term complications are extremely costly to treat.
Using cost-of-illness (COI) estimates instead of willingness-to-pay
(WTP) estimates to monetize the benefit from illness reduction
generally results in underestimating the actual benefits of these
reductions. In general, the COI approach is considered a lower bound
estimate of WTP because COI does not include pain and suffering. EPA
requests comment on the use of an appropriate WTP study to calculate
the reduction in illness benefits of this rule.
D. Incremental Costs and Benefits
Today's proposed rule options represent the incremental costs and
benefits of this rule. Both costs and benefits increase as more fecal
contamination detection measures are added to the sanitary surveys for
the first three options. The proposed option has the highest cost of
these three incremental options, but it also produces incrementally
more benefits.
[[Page 30248]]
The fourth option, across-the-board disinfection, is the most
costly because it would require all systems to install treatment or to
upgrade to 4-log removal/inactivation. It would not provide the
flexibility of the other three options and would not target
specifically high risk systems. Similar to the first three options,
this option also includes the sanitary survey provision. This is
included to address problems in the distribution systems and with
disinfection failure.
Table V-6 and Table V-6a show the monetized costs, benefits and net
benefits for all four options using both a three percent and seven
percent discount rate, respectively. It is important to remember that
non-quantified costs and benefits are not included in these net benefit
numbers.
Table V-6.--Net Benefits--3% Discount Rate ($Million)
----------------------------------------------------------------------------------------------------------------
Mean annual Mean annual Net benefits
Options costs (3%) benefits \1\ of the means
$million $million $million
----------------------------------------------------------------------------------------------------------------
Sanitary Survey................................................. $73 $33 ($40)
Sanitary Survey and Triggered Monitoring........................ 158 178 20
Multi-Barrier (Proposed)........................................ 183 205 22
Across-the-board Disinfection................................... 777 283 (494)
----------------------------------------------------------------------------------------------------------------
\1\ Does not include non-quantified benefits which would increase the net benefits of these rule options.
Table V-6a.--Net Benefits--7% Discount Rate ($Million)
----------------------------------------------------------------------------------------------------------------
Mean annual Mean annual
Options costs (7%) benefits \1\ Net benefits
$million $million $million
----------------------------------------------------------------------------------------------------------------
Sanitary Survey................................................. $76 $33 ($43)
Sanitary Survey and Triggered Monitoring........................ 169 178 9
Multi-Barrier (Proposed)........................................ 199 205 6
Across-the-board Disinfection................................... 866 283 (583)
----------------------------------------------------------------------------------------------------------------
\1\ Does not include non-quantified benefits which would increase the net benefits of these rule options.
E. Impacts on Households
Overall, the average annual cost per household for the first three
rule options are small across most system size categories as shown in
Table V-7. However, costs are greater for the smallest size category
across all options. This occurs because there are fewer households per
system to share the cost of any corrective action or monitoring
incurred by the systems. For example, under the Multi-Barrier option
household costs would increase by approximately $5 per month for those
served by the smallest size systems (100 people) while those served by
the largest size systems (>100,000 people) would face only a $0.02
increase in monthly household costs. As previously mentioned, the
majority of the cost from the first three rule options is the result of
systems having to correct significant deficiencies in their systems or
to take corrective action in response to fecal contamination. On
average, household costs resulting from the first three rule options
increase from $2.45 to $3.86 annually. The most expensive option,
across-the-board disinfection, also has the highest average household
costs at $19.37 annually.
Table V-7.--Average Annual Household Cost for GWR Options for CWS Taking Corrective Action or Fixing Significant
Defects
----------------------------------------------------------------------------------------------------------------
Sanitary
survey and Multi-barrier Across-the-
Size categories Sanitary triggered option board
survey option monitoring (proposed) disinfection
option option
----------------------------------------------------------------------------------------------------------------
100............................................. $29.86 $67.19 $62.48 $191.87
101-500......................................... 11.23 15.02 18.95 81.38
501-1,000....................................... 5.72 6.29 6.25 38.79
1,001-3,300..................................... 2.99 2.91 3.39 23.45
3,301-10,000.................................... 1.39 1.46 2.74 16.78
10,001-50,000................................... 0.62 0.59 0.62 4.87
50,001-100,000.................................. 0.30 0.70 1.01 10.37
100,001-1,000,000............................... 0.32 0.20 0.27 1.66
Average......................................... 2.45 3.34 3.86 19.37
----------------------------------------------------------------------------------------------------------------
[[Page 30249]]
F. Cost Savings From Simultaneous Reduction of Co-Occurring
Contaminants
If a system chooses to install treatment, it may choose a
technology that would also address other drinking water contaminants.
For example, when using packed tower aeration to treat radon, it is the
accepted engineering practice, and in some States an existing
requirement, to also install disinfection treatment for removal of
microbial contaminants introduced in the aeration treatment process.
Depending on the dosage and contact time, the routine disinfection
would also address possible or actual fecal contamination in the source
water. If systems had an iron or manganese problem, the addition of an
oxidant and filtration can treat this problem as well as fecal
contamination. Also, some membrane technologies installed to remove
bacteria or viruses can reduce or eliminate many other drinking water
contaminants including arsenic. EPA is currently in the process of
proposing rules to address radon and arsenic. Because of the
difficulties in establishing which systems would have all three
problems of fecal contamination, radon, and arsenic or any combination
of the three, no estimate was made of the potential cost savings from
addressing more than one contaminant simultaneously. EPA also
recognizes that while there may be savings from treating several
contaminants simultaneously relative to treating each of them
separately, there may also be significant economic impacts to some
systems (especially small systems), if they have to address several
contaminants in a relatively short time frame. Because of the lack of
good data on co-occurrence of contaminants, EPA has not considered
these simultaneous impacts in the analysis of household and per system
costs.
G. Risk Increases From Other Contaminants
The RIA for today's rule contains a detailed discussion of the
increased risk from other contaminants that may result from GWR
requirements. Most of the risk stems from currently untreated systems
installing disinfection. When disinfection is first introduced into a
previously undisinfected system, the disinfectant can react with pipe
scale causing increased risk from some contaminants and water quality
problems. Contaminants that may be released include lead, copper, and
arsenic. It could also lead to a temporary discoloration of the water
as the scale is loosened from the pipe. These risks can be reduced by
gradually phasing in disinfection to the system, by routine flushing of
distribution system mains and by maintaining a proper corrosion control
program.
Using a chlorine-based disinfectant or ozone could also result in
an increased risk from disinfection byproducts (DBPs). Risk from DBPs
has already been addressed in the Stage 1 Disinfection Byproducts Rule
and is currently being further considered by the Stage II M-DBP FACA.
Systems could avoid this problem by choosing an alternative
disinfection technology such as ultraviolet disinfection or membrane
filtration, though this may increase treatment costs. The GWR cost
estimate includes such additional treatment costs for a portion of
systems taking corrective action.
H. Other Factors: Uncertainty in Risk, Benefits, and Cost Estimates
Today's proposal models the current baseline risk from fecal
contamination in ground water as well as the reduction in risk and the
cost for four rule options. There is uncertainty in the baseline number
of systems, the risk calculation, the cost estimates, and the
interaction of other rules currently being developed. These
uncertainties are discussed further in the following section.
The baseline number of systems is uncertain because of data
limitations in the Safe Drinking Water Information System (SDWIS). For
example, some systems use both ground and surface water but because of
other regulatory requirements they are labeled in SDWIS as surface
water. Therefore, EPA does not have a reliable estimate of how many of
these mixed systems exist. To the extent that systems classified in
SDWS as surface water or ground water under the influence of surface
water may also have ground water wells not under the influence of
surface water and thus be subject to this rule, the costs and benefits
estimated here would be understated. In addition, the SDWIS data on
non-community water systems does not have a consistent reporting
convention for population served. Some States may report the population
served over the course of a year, while others may report the
population served on an average day. Also, SDWIS does not require
States to provide information on current disinfection practices and, in
some cases, it may overestimate the daily population served. For
example, a park may report the population served yearly instead of
daily. EPA is looking at new approaches to address these issues, and
both are discussed in the Requests for Comment section V.I.
The risk calculations concerning the baseline number of illnesses
and the reduction of illnesses that results from the various rule
options contains uncertainty. For example, a nationally representative
study of baseline microbial occurrence in ground water does not exist.
EPA chose the AWWARF study (described in section II.C.1) to represent
properly constructed wells because, of the thirteen available studies,
it is the most representative of national geology. EPA also relied on
data from the EPA/AWWARF study to represent improperly constructed
wells because this study targeted wells vulnerable to contamination and
tested wells monthly for a year. However, EPA recognizes the variable
nature of these studies, as discussed in detail in section II.C.
Additionally, EPA had to rely on CDC outbreak data to characterize the
causes of endemic ground water disease. As discussed in section II. B.,
the U.S. National Research Council suggests that CDC numbers only
represent a small percentage of actual waterborne disease outbreaks.
The Agency also assumes that the occurrence of fecal contamination will
remain constant throughout the implementation of the rule. However,
this might not be the case if increased development results in fecal
contamination of a larger number of aquifers in areas served by ground
water systems or if other rules, such as the TMDL, CAFO, and Class V
UIC Well Rules result in decreased fecal contamination.
EPA did not have dose-response data for all viruses and bacteria
associated with previous ground water disease outbreaks. For viral
illness, the Agency used echo and rota viruses as surrogates for all
pathogenic viruses from fecal contamination that can be found in ground
water. By using these two viruses, the Agency is capturing the effects
of both low-to-medium infectivity viruses that cause severe illness and
high infectivity viruses that cause more mild illness. Further, there
is considerable uncertainty in the dose-response functions used, even
for these two viruses. Dose-response was modeled in two steps. First,
infectivity, or the percentage of people in the different age groups
who become infected after exposure to a given quantity of water with a
given concentration of viruses, was estimated. Then morbidity, or the
percentage of infected people who actually become ill was estimated.
There is likely to be variability in both of these parameters across
populations and based on case specific circumstances, and only limited
data are available. Another uncertainty
[[Page 30250]]
concerns the number of baseline bacterial illness caused by ground
water contamination. The bacterial risk could not be modeled because of
lack of occurrence and dose-response data. Estimates of bacterial
illness were made based on a ratio of bacterial to viral outbreak as
documented by CDC and applied to the viral risk estimate discussed
previously. There is also considerable uncertainty in quantifying the
effectiveness of various regulatory options in reducing risk. There is
little data currently on which to base quantitative estimates of the
effectiveness of sanitary surveys or routine monitoring in reducing
microbial risk, though there is some qualitative research suggesting
that these can be effective strategies. To model risk reduction
quantitatively, EPA relied primarily on best professional judgment. The
quantitative estimates of risk reduction used in the analysis are
summarized in Table V-4a.
There is also uncertainty in the valuation of risk reduction
benefits. For this analysis EPA used a COI approach based on the direct
medical care costs as well as the indirect costs of becoming ill.
However, there is uncertainty in these estimates and variability in the
COI across populations and geographic regions. In general, however, COI
estimates understate benefits because they do not account for the value
people place on reduced pain and suffering.
Some costs of today's proposed rule are also uncertain because of
the diverse nature of possible significant deficiencies systems would
need to address. Also, the rule's flexibility leads to some uncertainty
in estimates of who will be affected by each rule component and how
States and systems will respond to significant deficiencies. These
uncertainties could either under or overestimate the costs of the rule.
EPA is in the process of proposing regulations for radon and
arsenic in drinking water, which can impact some ground water systems.
EPA also intends to finalize the Stage II Disinfection Byproducts Rule
by the statutory deadline of May 2002. It is extremely difficult to
estimate the combined effects of these future regulations on ground
water systems because of various combinations of contaminants that some
systems may need to address. However, it is possible for a system to
choose treatment technologies that would deal with multiple problems.
Therefore, the total cost impact of these drinking water rules is
uncertain; however, it may be less than the estimated total cost of all
individual rules combined. Conversely, the impacts on households and
individual systems of multiple rules is cumulative, and in some cases
maybe greater than the impacts estimated in the RIA of each rule
separately.
I. Benefit Cost Determination
The Agency has determined that the benefits of the proposed GWR
justify the costs. The mean quantified benefits exceed the mean
quantified costs by $22 million using a three percent discount rate and
$6 million using a seven percent discount rate. EPA made this
determination based on provisions of the multi-barrier option that
include improved sanitary surveys, hydrogeologic sensitivity
assessments triggered and routine monitoring provisions corrective
actions, and compliance monitoring. Overall, these elements will reduce
the risk of microbial contamination reaching the consumer. The
quantified cost of these provisions were compared to the monetized
benefits that result from the reduction in viral and bacterial illness
and death. In addition, other non-monetized benefits further justify
the costs of this rule.
J. Request for Comment
The Agency requests comment on all aspects of the GWR RIA.
Specifically, EPA seeks input into the following two issues.
1. NTNC and TNC Flow Estimates
In the GWR RIA, EPA estimates the cost of the GWR on NTNC and TNC
water systems by using flow models. However, these flow models were
developed to estimate flows only for CWS and they may not accurately
represent the much smaller flows generally found in NTNC and TNC
systems. The effect of the overestimate in flow would be to inflate the
cost of the rule for these systems. The Agency requests comment on an
alternative flow analysis for NTNC and TNC water systems described
next.
Instead of using the population served data to determine the
average flow for use in the rule's cost calculations, this alternative
approach would re-categorize NTNC and TNC water systems based on
service type (e.g., restaurants or parks). Service type would be
obtained from SDWIS data. However, service type data is not always
available because it is a voluntary SDWIS data field. Where
unavailable, the service type would be assigned based on statistical
analysis. Estimates of service type design flows would be obtained from
engineering design manuals and best professional judgment if no design
manual specifications exist.
In addition, each service type category would also have
corresponding rates for average population served and average water
consumption. These would be used to determine contaminant exposure
which is used in the benefit determination. Note that the current
approach of assuming that the entire population served drinks an
average of 1.2 liters per day for 250 days (from NTNCWSs) and 15 days
(from TNCWs) may lead to an overestimation of benefits. For example,
schools and churches would be two separate service type categories.
They each would have their own corresponding average design flow,
average population served (rather than the population as reported in
SDWIS), and average water consumption rates. These elements could be
used to estimate a rule's benefits and costs for the average church and
the average school.
2. Mixed Systems
Current regulations require that all systems that use any amount of
surface water as a source be categorized as surface water systems. This
classification applies even if the majority of water in a system is
from a ground water source. Therefore, SDWIS does not provide the
Agency with information to identify how many mixed systems exist. This
information would help the Agency to better understand regulatory
impacts. Further, to the extent that mixed systems are classified as
surface water, the costs and benefits of this proposed rule are
underestimated.
EPA is investigating ways to identify how many mixed systems exist
and how many mix their ground and surface water sources at the same
entry point or at separate entry points within the same distribution
systems. For example, a system may have several plants/entry points
that feed the same distribution system. One of these entry points may
mix and treat surface water with ground water prior to its entry into
the distribution system. Another entry point might use ground water
exclusively for its source while a different entry point would
exclusively use surface water. However, all three entry points would
supply the same system classified in SDWIS as surface water.
One method EPA could use to address this issue would be to analyze
CWSS data then extrapolate this information to SDWIS to obtain a
national estimate of mixed systems. CWSS data, from approximately 1,900
systems, details sources of supply at the level of the entry point to
the distribution system and further subdivides flow by source type. The
Agency is considering this
[[Page 30251]]
national estimate of mixed systems to regroup surface water systems for
certain impact analyses when regulations only impact one type of
source. For example, surface water systems that get more than 50
percent of their flow from ground water would be counted as a ground
water system in the regulatory impact analysis for this rule. The
Agency requests comment on this methodology and its applicability for
use in regulatory impact analysis.
VI. Other Requirements
A. Regulatory Flexibility Act (RFA), as Amended by the Small Business
Regulatory Enforcement Fairness Act of 1996 (SBREFA), 5 U.S.C. 601 et
seq.
1. Background
The RFA generally requires an agency to prepare a regulatory
flexibility analysis of any rule subject to notice and comment
rulemaking requirements under the Administrative Procedure Act or any
other statute unless the agency certifies that the rule will not have a
significant economic impact on a substantial number of small entities.
Small entities include small businesses, small organizations, and small
governmental jurisdictions.
2. Use of Alternative Definition
The RFA provides default definitions for each type of small entity.
It also authorizes an agency to use alternative definitions for each
category of small entity, ``which are appropriate to the activities of
the agency'' after proposing the alternative definition(s) in the
Federal Register and taking comment (5 U.S.C. secs. 601(3)--(5)). In
addition, agencies must consult with SBA's Chief Counsel for Advocacy
to establish an alternative small business definition.
EPA is proposing the GWR which contains provisions which apply to
small PWSs serving fewer than 10,000 persons. This is the cut-off level
specified by Congress in the 1996 Amendments to the Safe Drinking Water
Act for small system flexibility provisions. Because this definition
does not correspond to the definitions of ``small'' for small
businesses, governments, and non-profit organizations, EPA requested
comment on an alternative definition of ``small entity'' in the
preamble to the proposed Consumer Confidence Report (CCR) regulation
(63 FR 7620, February 13, 1998). Comments showed that stakeholders
support the proposed alternative definition. EPA also consulted with
the SBA Office of Advocacy on the definition as it relates to small
business analysis. In the preamble to the final CCR regulation (63 FR
4511, August 19, 1998). EPA stated its intent to establish this
alternative definition for regulatory flexibility assessments under the
RFA for all drinking water regulations and has thus used it in this
proposed rulemaking. The SBA Office of Advocacy agrees with the use of
this definition in this rulemaking.
3. Initial Regulatory Flexibility Analysis
In accordance with section 603 of the RFA, EPA prepared an initial
regulatory flexibility analysis (IRFA) that examined the impact of the
proposed rule on small entities along with regulatory alternatives that
could reduce that impact. The IRFA addresses the following issues:
The reasons the Agency is considering this action;
The objectives of, and legal basis for the proposed rule;
The number and types of small entities to which the rule
will apply;
Projected reporting, recordkeeping, and other compliance
requirements of the proposed rule, including the classes of small
entities which will be subject to the requirements and the type of
professional skills necessary for preparation of the reports and
records;
The other relevant Federal rules which may duplicate,
overlap, or conflict with the proposed rule; and,
Any significant alternatives to the components under
consideration which accomplish the stated objectives of applicable
statutes and which may minimize any significant economic impact of the
proposed rule on small entities.
a. The Reasons the Agency Is Considering This Action
EPA believes that there is a substantial likelihood that fecal
contamination of ground water supplies is occurring at frequencies and
levels which present public health concern. Fecal contamination refers
to the contaminants, particularly the microorganisms, contained in
human or animal feces. These microorganisms may include bacterial and
viral pathogens which can cause illnesses in the individuals which
consume them.
Fecal contamination is introduced to ground water from a number of
sources including, septic systems, leaking sewer pipes, landfills,
sewage lagoons, cesspools, and storm water runoff. Microorganisms can
be transported with the ground water as it moves through an aquifer. In
addition, the transport of microorganisms to wells or other ground
water system sources can also be affected by poor well construction
(e.g., improper well seals) which can result in large, open conduits
for fecal contamination to pass unimpeded into the water supply.
Waterborne pathogens contained in fecally contaminated water can
result in a variety of illnesses which range in the severity of their
outcomes from mild diarrhea to kidney failure or heart disease. The
populations which are particularly sensitive to waterborne and other
pathogens include, infants, young children, pregnant and lactating
women, the elderly and the chronically ill. These individuals may be
more likely to become ill as a result of exposure to the pathogens, and
are likely to have a more severe illness. A complete discussion of the
public health concerns addressed by the GWR can be found in section II
of the preamble.
b. The Objectives of, and the Legal Basis for, the Proposed Rule
EPA is proposing the GWR pursuant to section 1412(b)(8) of the
SDWA, as amended in 1996, which directs EPA to ``promulgate national
primary drinking water regulations requiring disinfection as a
treatment technique for all public water systems, including surface
water systems and, as necessary, ground water systems.''
The 1996 amendments establish a statutory deadline of May 2002.
EPA, however, intends to finalize the GWR in the year 2000 to coincide
with implementation of other drinking water regulations and programs,
such as the Disinfection Byproducts Rule, the Arsenic Rule, the Radon
Rule and the Source Water Assessment and Protection Program (SWAPP).
EPA believes systems and States will better plan for changes in
operation and capital improvements if they presented them with future
regulatory requirements at one time.
c. Number of Small Entities Affected
According to the December 1997 data from EPA's Safe Drinking Water
Information System (SDWIS), there are 156,846 community water systems
and non-community water supplies providing potable ground water to the
public, of which 155,254 (99 percent) are classified by EPA as small
entities. EPA estimates that these small ground water systems serve a
population of more than 48 million. Roughly one-quarter of these
systems are estimated to be community water systems serving fixed
populations on a year-round basis.
Under the proposed option, all community and non-community water
systems are affected by at least one requirement; the sanitary survey
provision. The other GWR components are estimated to affect different
numbers
[[Page 30252]]
of small systems. For example, over 4,300 small systems are expected to
have to fix significant deficiencies each year.
d. Small Entity Impacts
Reporting and Recordkeeping for the Proposed GWR
Under the proposed Multi-Barrier option, there are a number of
recordkeeping and reporting requirements for all ground water system
(including small systems). To minimize the burden with these
provisions, the EPA is proposing a targeted risk-based regulatory
strategy whereby the monitoring requirements are based on system
characteristics and not directly related to system size. In this
manner, the multi-barrier option takes a system-specific approach to
regulation, although a sanitary survey is required of all community and
non-transient non-community water systems. However, the implementation
schedule for this requirement is staggered (e.g., every three to five
years for CWSs and every five years for NCWSs), which should provide
some relief for small systems because there are proportionately more
NCWSs.
To address concerns over the potential cost of additional
monitoring for small systems, the proposed GWR leverages the existing
TCR monitoring framework to the extent possible (e.g., by using the
results of the routine TCR monitoring to determine if source water
monitoring is required). In this proposal, only systems that do not
reliably treat to 4-log inactivation or removal of viruses are required
to test for the presence of E. coli, coliphage, or enterococci in the
source water within 24 hours of a total coliform positive sample in the
distribution system.
Only systems determined to be hydrogeologically sensitive and do
not already treat to 4-log inactivation or removal of viruses are
required to conduct the additional routine monitoring. If no fecal
indicators are found after 12 months of monitoring, the State may
reduce the monitoring frequency for that system. Similarly, if a non-
sensitive system does not have a distribution system, any sample taken
for TCR compliance is effectively a source water sample, so an
additional triggered source water sample would not be required. In both
cases, however, if the system has a positive sample for E. coli,
coliphage, or fecal coliform, the system is required to conduct the
necessary follow-up actions.
Small Entity Compliance Costs for the Proposed GWR
Estimates of the cost of complying with each component of the
multi-barrier approach are presented next. The estimated impacts for
this proposed option are based on the national mean compliance cost
across the four compliance scenarios. System-level impacts are
investigated using various corrective action and significant defects
scenarios. The high correction action/low significant defect scenario
is considered a typical cost estimate. For more information on these
scenarios and cost assumptions, consult the Regulatory Impact Analysis
for the Proposed Ground Water Rule (USEPA, 1999a) which is available
for review in the water docket.
In determining the costs and benefits of this proposed rule, EPA
considered the full range of both potential costs and benefits for the
rule. The flexibility of the risk-based targeted approach of the rule
aims to reduce the cost of compliance with the rule. Small systems will
benefit from the flexibility provided in this design. For example, a
small system with fecal contamination will, in consultation with the
State, be able to select the least costly corrective action. Also,
small systems serving less than 3,300 people which disinfect will only
be required to monitor their treatment effectiveness one time per day
as opposed to the continuous monitoring required for larger systems
which disinfect. Estimates of annual CWS compliance costs for the
multi-barrier approach are presented in Table VI-1.
Table VI-1.--Annual Compliance Costs for the Proposed GWR by CWS System Size and Type
----------------------------------------------------------------------------------------------------------------
System size/population served
CWS system type -------------------------------------------------------------------------------
100 101-500 501-1,000 1,001-3,300 3,301-10K
----------------------------------------------------------------------------------------------------------------
Publicly-Owned.................. $825 $934 $1,238$ $1,950 $4,480
Privately-Owned................. 799 933 1,449 1,730 5,358
All Systems..................... 805 933 1,328 1,893 4,652
----------------------------------------------------------------------------------------------------------------
e. Coordination With Other Federal Rules
To avoid duplication of effort, the proposed GWR encourages States
to use their source water assessments when the assessment provides data
relevant to the sensitivity assessment of a system. Although not a
regulatory program, source water assessments are currently being
performed by States. The schedule for the sensitivity assessment
(within six years for CWS and eight years for NCWS) should allow States
to complete the assessment and the first round of sanitary surveys
concurrently if they choose to do so.
EPA has structured this GWR proposal as a targeted, risk-based
approach to reducing fecal contamination. The only regulatory
requirement that applies to all ground water systems is the sanitary
survey. The Agency has also considered other drinking water
contaminants that may be of concern when a system install disinfection.
Specifically, adding disinfection may result in an increase in other
contaminants of concern, depending on the characteristics of the source
water and the distribution system. These contaminants include
disinfection byproducts, lead, copper, and arsenic. EPA believes that
these issues, when they occur will be very localized and may be
addressed through selection of the appropriate corrective action. EPA
has provided States and systems with the flexibility to select among a
variety of corrective actions. These include options such as UV
disinfection, or purchasing water from another source, which would
avoid these types of problems.
f. Minimization of Economic Burden
Description of Regulatory Options
As a result of the input received from stakeholders, the EPA
workgroup, and other interested parties, EPA constructed four
regulatory options:
The sanitary survey option, the sanitary survey and triggered
monitoring option, the multi-barrier option, and the across-the-board
disinfection option. These options are described in more detail in
section III of this preamble.
On an annual basis, the cost of the proposed alternative ranges
from $182.7 million to $198.6 million, using a three and seven percent
discount rate. System costs make up 89 percent of the total
[[Page 30253]]
rule costs. In developing this proposal, however, EPA considered the
recommendations to minimize the cost impact to small systems. The
proposed multi-barrier, risk-based approach was designed to achieve
maximum public health protection while avoiding excessive compliance
costs associated with Across-the-Board Disinfection regulatory
compliance requirements.
To mitigate the associated compliance cost increases across water
systems, the proposed GWR also provides States with considerable
flexibility when implementing the rule. This flexibility will allow
States to work within their existing program. Similarly, the rule
allows States to consider the characteristics of individual systems
when determining an appropriate corrective action. For example, States
have the flexibility to allow systems to obtain a new source, or use
any disinfection treatment technology, provided it achieves 4-log
inactivation or removal of pathogens.
4. Small Entity Outreach and Small Business Advocacy Review Panel
As required by section 609(b) of the RFA, as amended by SBREFA, EPA
also conducted outreach to small entities and convened a Small Business
Advocacy Review Panel to obtain advice and recommendations of
representatives of the small entities that potentially would be subject
to the rule's requirements. The SBAR Panel members for the GWR were the
Small Business Advocacy Chair of the Environmental Protection Agency,
the Director of the Standards and Risk Management Division in the
Office of Ground Water and Drinking Water (OGWDW) within EPA's Office
of Water, the Administrator for the Office of Information and
Regulatory Affairs of the Office of Management and Budget (OMB), and
the Chief Counsel for Advocacy of the Small Business Administration
(SBA). The Panel convened on April 10, 1998, and met seven times before
the end of the 60-day Panel period on June 8, 1998. The SBAR Panel's
report Final Report of the SBREFA Small Business Advocacy Review Panel
on EPA's Planned Proposed Rule for National Primary Drinking Water
Regulations: Ground Water, the small entity representatives (SERs)
comments on components of the GWR, and the background information
provided to the SBAR Panel and the SERs are available for review in the
Office of Water docket. This information and the Panel's
recommendations are summarized in section VI.A.4.a.
Prior to convening the SBAR Panel, EPA consulted with a group of 22
SERs likely to be impacted by a GWR. The SERs included small system
operators, local government officials (including elected officials),
small business owners (e.g., a bed and breakfast with its own water
supply), and small nonprofit organizations (e.g., a church with its own
water supply for the congregation). The SERs were provided with
background information on the GWR, on the need for the rule and the
potential requirements. The SERs were asked to provide input on the
potential impacts of the rule from their perspective. All 22 SERs
commented on the information provided. These comments were provided to
the SBAR Panel when the Panel convened. After a teleconference between
the SERs and the Panel, the SERs were invited to provide additional
comments on the information provided. Three SERs provided additional
comments on the rule components after the teleconference. In general,
the SERs consulted on the GWR were concerned about the impact of the
rule on small water systems (because of their small staff and limited
budgets), the additional monitoring that might be required, and the
data and resources necessary to conduct a hydrogeologic sensitivity
assessment or sanitary survey. There was also considerable discussion
about how nationally representative the source data was. SER suggested
providing flexibility to the States implementing these provisions and
opposed mandatory disinfection across-the-board. SERs expressed support
for existing monitoring requirements as a means of determining
compliance, and some supported increased requirements for total
coliform monitoring.
Consistent with the RFA/SBREFA requirements, the Panel evaluated
the assembled materials and small-entity comments related to the
elements of the IRFA. A copy of the Panel report is in the Office of
Water docket for this proposed rule.
a. Number of Small Entities to Which the Rule Will Apply
When the IRFA was prepared, EPA estimated that there were over
157,000 small ground water systems that could be affected by the GWR,
serving a population of more than 48 million. Roughly one-third of
these systems are community water systems (CWS). The remainder are non-
community water systems (NCWS) (i.e. non-transient non-community such
as schools and transient non-community such as restaurants). A more
detailed and current discussion of the impact of the proposed rule on
small entities can be found in section V of this preamble.
The SBAR Panel recommended that, given the number of systems that
could be affected by the rule, EPA should consider focusing compliance
requirements on those systems most at risk of fecal contamination. The
GWR addresses this issue and is designed to target the systems at
highest risk. Risk characterization is based on system characteristics,
i.e., significant deficiencies in operation or maintenance and
hydrogeologic sensitivity to contamination. A system is not required to
perform an action such as source water microbial monitoring until the
State has cause to believe the system is at risk.
The Panel also recommended that the rule requirements be based on
system size. Because the GWR is a targeted risk-based rule, the
regulatory strategy is based on system-specific risk indicators that
are not directly related to system size. However, the monitoring
required for treatment effectiveness (compliance monitoring) varies
based on system size. Ninety-seven percent of all ground water systems
serve less than 3,300 people. Under the proposed GWR, disinfecting
ground water systems serving less than 3,300 people must monitor
treatment by taking daily grab samples. Disinfecting ground water
systems serving 3,300 or more people must monitor treatment
continuously.
The SBAR Panel advocated that States be provided with flexibility
when implementing the rule. The GWR also addresses this issue. As
discussed earlier in sections III.A.1. and 2. of this proposal, States
have considerable flexibility in addressing potential problems in small
systems. In particular, States have the flexibility to define and
identify significant system deficiencies and to describe their
approaches to identifying the presence of hydrogeologic barriers to
contamination. States also have the flexibility to require correction
of fecal contamination or use any disinfection treatment technology,
provided it achieves 4-log (99.99%) inactivation or removal of viruses.
Similarly, the rule allows States to consider the characteristics of
individual systems when determining an appropriate corrective action.
b. Record Keeping and Reporting and Other Compliance Requirements
Because small systems frequently have minimal staff and resources,
including data on the underlying hydrogeology of the system, the SBAR
Panel recommended that EPA focus the record keeping, reporting, and
compliance requirements on those systems at greatest risk of fecal
[[Page 30254]]
contamination. The Panel also recommended that EPA consider tailoring
the requirements based on system size (e.g., the smaller systems would
not have to monitor as frequently or perform sanitary surveys on the
same schedule.)
The GWR proposed today is a targeted risk-based regulatory
strategy. The regulatory strategy is based on system characteristics
(i.e., hydrogeologic sensitivity; TCR positive in the distribution
system) and is not directly related to system size. However, the
monitoring required for treatment effectiveness (compliance monitoring)
varies based on system size. Ninety-seven percent of all ground water
systems serve less than 3,300 people. Under the proposed GWR,
disinfecting ground water systems serving less than 3,300 people must
monitor treatment by taking daily grab samples. Disinfecting ground
water systems serving 3,300 or more people must monitor treatment
continuously. In addition, the only across-the-board requirement is for
sanitary surveys, but the implementation schedule is staggered (e.g.,
every 3 years for CWS and every 5 years for NCWS) which should provide
some relief for small systems because there are proportionately more
that are NCWS. EPA is also requesting comment on several options that
would reduce the required frequency of sanitary surveys. Because many
small systems may not have easy access to the records that would
ideally be available for a hydrogeologic sensitivity assessment or a
sanitary survey, EPA, after consulting with stakeholders and the SBAR
Panel, has determined that it will not use the lack of adequate well
records, the lack of a cross connection program, or intermittent
pressure fluctuations as automatic triggers to indicate risk of
potential contamination. These factors may be considered along with
others that more definitively demonstrate risk. This strategy will
enable States to focus their resources on the systems which need the
most surveillance or follow-up action and will avoid penalizing systems
with limited resources.
With respect to the potential cost of additional monitoring for
small systems, particularly if the rule required viral monitoring, the
SBAR Panel offered several recommendations. First, the Panel suggested
that, to the extent possible, the GWR should build on the existing
monitoring framework in the TCR. Given the low cost of the Total
Coliform test, the Panel noted that an increase in the frequency and
the locations for TCR monitoring or additional samples in the source
water if the system has a Total Coliform positive sample would be
preferable to other fecal indicator tests, given the current cost of a
viral test. However, the Panel also recommended that the EPA continue
to develop a lower cost, more accurate test to identify viral and
bacterial contamination in drinking water.
Today's proposal does build on the existing TCR monitoring
framework by using the results of the TCR monitoring to determine if
source water monitoring is required. In the proposal, a system is
required to test for the presence of E. coli, coliphage, or enterococci
in the source water within 24 hours of a total coliform positive sample
in the distribution system. Only systems determined to be
hydrogeologically sensitive that do not already treat their water to 4-
log inactivation or removal are required to conduct the additional
routine monitoring. These systems must test their source water monthly.
If no fecal indicators are found after 12 consecutive months of
monitoring, the State may reduce the monitoring frequency for that
system. Similarly, if a non-sensitive system does not have a
distribution system, any sample taken for TCR compliance is effectively
a source water sample so an additional triggered source water sample
would not be required. In both cases, however, if the system has an E.
coli, coliphage, or fecal coliform positive sample, the system is
required to conduct the necessary follow-up actions.
The GWR also has incorporated low-cost fecal contamination
indicator tests. EPA-approved methods for detecting bacterial
indicators of fecal contamination, including E. coli and enterococci,
are already widely used and are low cost (approximately $25 per
sample). In addition, EPA is currently developing viral monitoring
methods which will cost approximately the same as existing bacterial
methods.
The SBAR Panel recommended that States be provided with flexibility
when implementing the rule. For example, while States must have the
authority to require the correction of significant deficiencies, States
should also have the flexibility to determine which deficiencies are
``significant'' from a public health perspective. When a State
determines that corrective action is necessary, it should have the
flexibility to determine what actions a system should take, including
but not limited to disinfection. Similarly, States should also have the
flexibility to require disinfection across-the-board for all or a
subset of the public water supply systems in their State. States should
also be given the flexibility to choose from the full range of
disinfection technologies that will meet the public health goals of the
rule.
As discussed earlier in sections III.A.1. and 2. of this proposal,
States have considerable flexibility in addressing potential problems
in small systems particularly with respect to sanitary survey, where
States define and identify significant deficiencies, and in conducting
hydrogeologic sensitivity assessments. The GWR allows States
flexibility to work within their existing programs and define and
identify significant deficiencies. States also have the flexibility to
require correction of fecal contamination or use any disinfection
treatment technology, provided it achieves 4-log (99.99%) inactivation
or removal of viruses. Similarly, the rule allows States to consider
the characteristics of individual systems when determining an
appropriate corrective action.
The Panel was also concerned about the potential cost of
disinfection and recommended that EPA include a full range of variables
when determining both the potential cost burden and benefits of the
rule.
In determining the costs and benefits of today's proposed rule, EPA
considered the full range of both potential costs and benefits for the
rule. The flexibility in the rule is designed to reduce the cost of
compliance with the rule, particularly for small systems. While
determining the costs of the various technologies, EPA has estimated
the percentage of systems in consultation with the States that will
choose between the different technologies, in part based on system
size. When determining the benefits of today's proposal, EPA considered
a range of benefits from reduction in illness and mortality to outbreak
cost avoided and possibly reduced uncertainty and averting behaviors.
However, only reductions in acute viral and bacterial illness and
decreases in mortality from virus are monetized. More detailed cost and
benefit information is included in the GWR RIA (US EPA, 1999a) for
today's proposal. Because systems are highly variable, the SBAR Panel
recommended that States be given the flexibility to determine
appropriate maintenance or cross connection control measures for each
system and to the extent practicable maintenance measures should be
performance-based.
EPA recognizes that systems' characteristics are highly variable.
States have considerable flexibility when working with systems to
address significant deficiencies, conduct hydrogeological sensitivity
assessments,
[[Page 30255]]
and take corrective action. Cross connection control will be considered
under a future rulemaking (i.e., the Long Term 2 Enhanced Surface Water
Treatment Rule).
c. Other Federal Rules
To avoid duplication of effort, the SBAR Panel recommended using
the State Source Water Assessment and Protection Program (SWAPP) plans
and susceptibility assessments as a component of the hydrogeologic
sensitivity assessment process. To further streamline the process,
especially for small systems, the Panel also recommended combining the
hydrogeologic sensitivity assessment with the sanitary surveys.
In today's GWR proposal, States are encouraged to use their SWAPP
assessments when the assessment provides data relevant to the
hydrogeologic sensitivity assessment of a system. The schedule for
sensitivity assessments (six years after the GWR is promulgated in the
Federal Register for CWS and eight years after the GWR is promulgated
in the Federal Register for NCWS) should allow States to complete the
assessment and the first round of sanitary surveys concurrently if they
choose to do so.
d. Significant Alternatives
Because the SBREFA consultation was conducted early in the
regulatory development process before there was a draft proposal, few
comments were received on specific regulatory alternatives. In general,
the SERs supported the approach described in the outreach materials
while at the same time commenting on particular aspects of the approach
that might be burdensome or otherwise problematic. Their concerns echo
the comments received on other parts of the IRFA.
The SBAR Panel reiterated their suggestion that compliance
requirements be tailored to the system size. In particular, if the
minimum monitoring frequency and the frequency for sanitary surveys for
the smallest systems (e.g., those serving less than 500 people) could
be reduced, it would reduce both the resources necessary to comply with
the rule and record keeping required by the system.
EPA has structured today's proposal as a targeted risk-based
approach to reducing fecal contamination. The only requirement that
affects all GWSs is the sanitary survey. The required frequency for
sanitary surveys for community systems is once every three years which
may be changed by the State to once every five years if the system
either treats to 4-log inactivation or removal of virus or has an
outstanding performance record documented in previous inspections and
has no history of total coliform MCL or monitoring violations since the
last sanitary survey under current ownership. The required frequency
for sanitary surveys is once every five years for noncommunity systems.
The majority of the small systems are noncommunity systems so the
majority of systems will only have a sanitary survey once every five
years. At this frequency, EPA believes that the requirements will not
be burdensome for even the smallest systems, however EPA is also
requesting comment on less frequent sanitary survey requirements.
Similarly, the only additional monitoring requirements in today's
proposal are for undisinfected systems that are either located in
sensitive hydrogeologic settings or have a total coliform positive
sample in the distribution system. The monitoring required for a total
coliform positive sample under the TCR would be a one-time event while
the monitoring for sensitive systems would be on a routine monthly
basis for at least 12 samples.
Finally, the SBAR Panel noted that disinfection of public water
supplies may result in an increase in other contaminants of concern,
depending on the characteristics of the source water and the
distribution system. Of particular concern were disinfection
byproducts, lead, copper, and arsenic.
EPA has discussed these issues previously in section V.G. of the
GWR preamble. EPA believes that these issues, when they occur, will
typically be localized and transitory. These risk/risk tradeoffs are
considered qualitatively in the RIA and EPA will provide guidance on
how to address these issues when the rule is finalized.
e. Other Comments
The panel members could not reach consensus regarding the use of
occurrence data to support the rule. Some panel members expressed the
concern that the occurrence estimates discussed by EPA with the SERs
overestimated the actual occurrence of fecal contamination and the
studies used did not provide a true picture of national occurrence. EPA
recognizes and understands the concerns about the available data
expressed by these panel members. However, the Agency believes, after
consulting with experts in the field, that the available data may
underestimate the extent of ground water contamination because of
limitations with sampling methods and frequency. EPA believes that a
central issue for all participants and stakeholders in this rulemaking
is how to interpret the available data. EPA agrees that the GWR must be
based on the best available data, good science and sound analysis. The
studies described in the materials presented to the SERs and SBAR Panel
during the SBREFA process were conducted at different times and for
different reasons; each requires careful analysis to ensure its proper
use and to avoid misuse. A more detailed discussion of the occurrence
studies and request for comment on their interpretation is provided in
section II.C. of today's proposal.
EPA invites comments on all aspects of the proposal and its impacts
on small entities.
B. Paperwork Reduction Act
The information collection requirements in this proposed rule have
been submitted for approval to the Office of Management and Budget
(OMB) under the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. An
Information Collection Request (ICR) document has been prepared by EPA
(ICR No. 1934.01) and a copy may be obtained from Sandy Farmer by mail
at Collection Strategies Division; U.S. Environmental Protection Agency
(2822); 1200 Pennsylvania Ave., NW, Washington, DC 20460, by email at
[email protected], or by calling (202) 260-2740. A copy may
also be downloaded from the Internet at http://www.epa.gov/icr. For
technical information about the collection contact Jini Mohanty by
calling (202) 260-6415.
The information collected as a result of this rule will allow the
States and EPA to make decisions and evaluate compliance with the rule.
For the first three years after the promulgation of the GWR, the major
information requirements are for States and PWSs to prepare for
implementation of the rule. The information collection requirements in
Part 141, for systems, and Part 142, for States are mandatory. The
information collected is not confidential.
EPA estimates that the annual burden on PWSs and States for
reporting and record keeping will be 326,215 hours. This is based on an
estimate that 56 States and territories will each need to provide 3
responses each year with an average of 524 hours per response, and that
52,331 systems will each provide 2.3 responses each year with an
average of less than 2 hours per response. The labor burden is
estimated for the following activities: Reading and understanding the
rule, planning, training, and meeting primacy requirements. The
recordkeeping and reporting burden also includes capital costs of
$1,376,302 for capital
[[Page 30256]]
improvements by PWSs (installation of disinfection monitoring
equipment).
Burden means the total time, effort, or financial resources
expended by persons to generate, maintain, retain, or disclose or
provide information to or for a Federal agency. This includes the time
needed to review instructions; develop, acquire, install, and utilize
technology and systems for the purposes of collecting, validating, and
verifying information, processing and maintaining information, and
disclosing and providing information; adjust the existing ways to
comply with any previously applicable instructions and requirements;
train personnel to be able to respond to a collection of information;
search data sources; complete and review the collection of information;
and transmit or otherwise disclose the information.
An Agency may not conduct or sponsor, and a person is not required
to respond to a collection of information unless it displays a
currently valid OMB control number. The OMB control numbers for EPA's
regulations are listed in 40 CFR Part 9 and 48 CFR Chapter 15.
Comments are requested on the Agency's need for this information,
the accuracy of the provided burden estimates, and any suggested
methods for minimizing respondent burden, including the use of
automated collection techniques. Send comments on the ICR to the
Director, Collection Strategies Division; U.S. Environmental Protection
Agency (2822); 1200 Pennsylvania Ave, N.W.; Washington, DC 20460; and
to the Office of Information and Regulatory Affairs, Office of
Management and Budget, 725 17th St., N.W., Washington, DC 20503, marked
``Attention: Desk Officer for EPA.'' Include the ICR number in any
correspondence. Since OMB is required to make a decision concerning the
ICR between 30 and 60 days after May 10, 2000, a comment to OMB is best
assured of having its full effect if OMB receives it by June 9, 2000.
The final rule will respond to any OMB or public comments on the
information collection requirements contained in this proposal.
C. Unfunded Mandates Reform Act
1. Summary of UMRA Requirements
Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Public
Law 104-4, establishes requirements for Federal agencies to assess the
effects of their regulatory actions on State, local, and tribal
governments and the private sector. Under UMRA section 202, EPA
generally must prepare a written statement, including a cost-benefit
analysis, for proposed and final rules with ``Federal mandates'' that
may result in State, local and tribal government expenditures, in the
aggregate, or private sector expenditures, of $100 million or more in
any one year. Before promulgating an EPA rule, for which a written
statement is needed, section 205 of the UMRA generally requires EPA to
identify and consider a reasonable number of regulatory alternatives
and adopt the least costly, most cost-effective or least burdensome
alternative that achieves the objectives of the rule. The provisions of
section 205 do not apply when they are inconsistent with applicable
law. Moreover, section 205 allows EPA to adopt an alternative other
than the least costly, most cost effective or least burdensome
alternative if the Administrator publishes with the final rule an
explanation why that alternative was not adopted.
Before EPA establishes any regulatory requirements that may
significantly or uniquely affect small governments, including tribal
governments, it must have developed, under section 203 of the UMRA, a
small government agency plan. The plan must provide for notification to
potentially affected small governments, enabling officials of affected
small governments to have meaningful and timely input in the
development of EPA regulatory proposals with significant Federal
intergovernmental mandates; and informing, educating, and advising
small governments on compliance with the regulatory requirements.
2. Written Statement for Rules With Federal Mandates of $100 Million or
More
EPA has determined that this rule contains a Federal mandate that
may result in expenditures of $100 million or more for the private
sector in any one year.
Table VI-2 presents a breakdown of the estimated $182.7 to$198.6
million annual cost for today's proposed rule (the proposed Multi-
Barrier Option). Public ground water systems owned by State, local and
tribal governments will incur $51.2 to $56.5 million of these costs and
States will incur an additional $20.1 to $22.1 million for a total
public sector cost of $71.3 to $78.7 million dollars per year. Public
ground water systems which are owned by private entities will incur a
total cost of $111.5 to $ 119.9 million per year, $5.5 to $7 million of
which is incurred by entities that operate a public water system as a
means of supporting their primary business (e.g., a mobile home park
operator).
Table VI-2.--Public and Private Costs for of the Proposed GWR
------------------------------------------------------------------------
Percent
Annual mean cost range* of
System type (millions $) total
cost
------------------------------------------------------------------------
Public PWS Cost...................... $51.2 to $56.5.......... 28
State Cost........................... 20.1 to 22.1............ 11
----------------------------------
Total Public Cost.................... 71.3 to 78.7............ 40
==================================
Private PWS Cost..................... 106.0 to 113.0.......... 57
Ancillary PWS Cost................... 5.5 to 7.0.............. 4
----------------------------------
Total Private Cost............... 111.5 to 119.9.......... 60
==================================
Total Cost....................... 182.7 to 198.6.......... 100
------------------------------------------------------------------------
Note: Cost range based upon a 3% and 7% discount rate.
Thus, today's rule is subject to the requirements of sections 202
and 205 of the UMRA, and EPA has prepared a written statement which is
summarized next. A more detailed description of this analysis is
presented in EPA's Regulatory Impact Analysis of the GWR (US EPA,
1999a) which is included in the Office of Water docket for this rule.
a. Authorizing Legislation
Today's proposed rule is promulgated pursuant to section 1412(b)(8)
of the SDWA, as amended in 1996, which directs EPA to ``promulgate
national primary drinking water regulations requiring disinfection as a
treatment technique for all public water systems, including surface
water systems and, as necessary, ground water systems.''
Section 1412 (b)(8) also establishes a statutory deadline for
promulgation of the GWR of no later than the date on which the
Administrator promulgates a Stage II rulemaking for disinfectants and
disinfection byproducts. EPA intends to finalize the GWR in the year
2000 to allow systems to consider the combined impact of this rule, the
radon rule, the arsenic rule and the Stage 1 DBP rule on their design
and treatment modification as well as their capital investment
decisions. EPA believes States and systems will better plan for changes
in operation and capital improvements, if they are presented with
future requirements at one time.
b. Cost Benefit Analysis
Section V of this preamble discusses the cost and benefits
associated with the GWR . Also, EPA's Regulatory Impact Analysis of the
GWR (US EPA, 1999a) contains a detailed cost benefit analysis. The
analysis quantifies cost and benefits for four scenarios: the proposed
regulatory option, the sanitary survey
[[Page 30257]]
option, the sanitary survey and triggered monitoring option, and the
across-the-board disinfection option. Table VI-3 summarizes the range
of annual costs and benefits for each rule option.
Table VI-3.--Annual Benefits and Costs of Rule Options ($Million)
----------------------------------------------------------------------------------------------------------------
Annual benefits Annual costs (3%) Annual costs \2\
Option \1\ mean [range] mean [range] (7%) mean
$million $million [range] $million
----------------------------------------------------------------------------------------------------------------
Sanitary Survey..................................... $33 $73 $76
[$9 to $58] [$71 to $74] [$74 to $78]
Sanitary Survey and Triggered Monitoring............ $178 $158 $169
[$147 to $209] [$152 to $19] [$163 to $174]
Multi-barrier (Proposed ) Option.................... $205 $183 $199
[$169 to $242] [$177 to $188] [$192 to $206]
Across-the-Board Disinfection....................... $283 $777 $866
[$255 to $311] [$744 to $810] [$823 to $909]
----------------------------------------------------------------------------------------------------------------
\1\ does not include benefits from reduction in chronic illness, reduced pain and suffering, or non-health
benefits.
\2\ does not include non-quantified costs such as land acquisition or increases in other contaminants (e.g.,
DBPs).
Costs varied with each option and were driven by the number of
systems that would need to fix a significant deficiency, take
corrective action in response to fecal contamination, or install
treatment. The annual mean cost of the four rule options ranges from
$73 million to $866 million using a three percent and seven percent
discount rate. For the first three options, the costs increase as more
components are added for identifying fecally contaminated wells and
wells sensitive to fecal contamination. However, the cost of these
components (e.g., hydrogeologic sensitivity assessment, routine and
triggered monitoring) are minor compared to the costs of correcting
fecal contamination. The fourth option of across-the-board disinfection
is the most costly because it would require all systems to have
treatment regardless of actual or potential fecal contamination. Costs
for the States to implement this rule are also included in the four
cost estimates. Some costs, such as land acquisition where necessary to
install treatment, were not included because of the difficulty of
estimating them.
These total annual monetized costs can be compared to the annual
monetized benefits of the GWR. The annual monetized mean benefits of
today's rule range from $33 million to $283 million as shown in Table
VI-2. This result is based on the quantification of the number of acute
viral illnesses and deaths avoided attributable to each option as well
as the reduction in acute bacterial illness attributable to each
option. For illness, EPA used a cost-of-illness number to estimate the
benefits from the reduction in viral illness that result from this
rule. This is considered a lower-bound estimate of actual benefits
because it does not include the pain and discomfort associated with the
illness. Mortalities were valued using a value of statistical life
estimate consistent with EPA policy.
This rule will also decrease bacterial illness associated with
fecal contamination of ground water. EPA did not directly calculate the
actual numbers of illness associated with bacterially contaminated
ground water because the Agency lacked the necessary pathogen
occurrence data to include it in the risk model. However, in order to
get an estimate of the number of bacterial illness from fecally
contaminated ground water, the Agency used the ratio of viral and
unknown etiology outbreak illness to bacterial outbreak illnesses
reported to CDC's for waterborne outbreaks in ground water. It was
further assumed that the cost of these bacterial illnesses would be
comparable to viral illness estimates. This rule also considered but
did not monetize the health benefit from the reduction in chronic
illness associated with some viral and bacterial infections (see
section II.D.).
Various Federal programs exist to provide financial assistance to
State, local, and tribal governments in complying with this rule. The
Federal government provides funding to States that have primary
enforcement responsibility for their drinking water programs through
the Public Water Systems Supervision Grants Program. Additional funding
is available from other programs administered either by EPA or other
Federal agencies. These include EPA's Drinking Water State Revolving
Fund (DWSRF), U.S. Department of Agriculture's Rural Utilities' Loan
and Grant Program, and Housing and Urban Development's Community
Development Block Grant Program.
For example, SDWA authorizes the Administrator of the EPA to award
capitalization grants to States, which in turn can provide low cost
loans and other types of assistance to eligible public water systems.
The DWSRF assists public water systems with financing the costs of
infrastructure needed to achieve or maintain compliance with SDWA
requirements. Each State has considerable flexibility in determining
the design of its DWSRF Program and to direct funding toward its most
pressing compliance and public health protection needs. States may
also, on a matching basis, use up to 10 percent of their DWSRF
allotments for each fiscal year to assist in running the State drinking
water program. In addition, States have the flexibility to transfer a
portion of funds to the Drinking Water State Revolving Fund from the
Clean Water State Revolving Fund.
Furthermore, a State can use the financial resources of the DWSRF
to assist small systems, the majority of which are ground water
systems. In fact, a minimum of 15% of a State's DWSRF grant must be
used to provide infrastructure loans to small systems. Two percent of
the State's grant may be used to provide technical assistance to small
systems. For small systems that are disadvantaged, up to 30% of a
State's DWSRF may be used for increased loan subsidies. Under the
DWSRF, Tribes have a separate set-aside which they can use.
In addition to the DWSRF, money is available from the Department of
Agriculture's Rural Utility Service (RUS) and Housing and Urban
Development's Community
[[Page 30258]]
Development Block Grant (CDBG) program. RUS provides loans, guaranteed
loans, and grants to improve, repair, or construct water supply and
distribution systems in rural areas and towns up to 10,000 people. In
Fiscal Year 1997, the RUS had over $1.3 billion in available funds.
Also, three sources of funding exist under the CDBG program to finance
building and improvements of public facilities such as water systems.
The three sources of funding include: (1) direct grants to communities
with populations over 200,000; (2) direct grants to States, which they
in turn award to smaller communities, rural areas, and colonias in
Arizona, California, New Mexico, and Texas; and (3) direct grants to
US. Territories and Trusts. The CDBG budget for Fiscal Year 1997
totaled over $4 billion dollars.
c. Estimates of Future Compliance Costs and Disproportionate Budgetary
Effects
To meet the UMRA requirement in section 202, EPA analyzed future
compliance costs and possible disproportionate budgetary effects. The
Agency believes that the cost estimates, indicated earlier and
discussed in more detail in section V of this rule, accurately
characterize future compliance costs of the proposed rule.
In analyzing disproportionate impacts, the Agency considered three
measures: reviewing the impacts on small systems versus large systems;
reviewing the costs to public versus private water systems; and
reviewing the household costs for each proposed rule option. It is also
possible that some States or EPA Regions may face greater challenges
from the GWR because they have comparatively more ground water systems.
However, States that have a larger percentage of systems also receive a
greater share of the Public Water Systems Supervision Grants Program
and the DWSRF. A detailed analysis of these impacts is presented in the
Regulatory Impact Analysis of the GWR (US EPA, 1999a).
The first measure of disproportionate impact considers the cost
incurred by small and large systems. As a group, small systems will
experience a greater impact than large systems under the GWR. The
higher cost to the small ground water systems is mostly attributable to
the large number of these types of systems (i.e., 99% of ground water
systems serve 10,000). Other reasons for the disparity include: (1)
Large systems are more likely to already disinfect their ground water
(disinfection exempts a system from triggered and routine monitoring),
(2) large systems typically have greater technical and operational
expertise, and (3) they are more likely to engage in source water
protection programs. The potential economic impact among the small
systems will be the greatest for systems serving less than 100 persons,
as shown in Table VI-4.
Table VI-4.--Average Annual Household Costs for GWR Options for CWS Taking Corrective Action or Fixing
Significant Defects
----------------------------------------------------------------------------------------------------------------
Sanitary survey Across-the-board
Size categories Sanitary survey and triggered Multi-barrier disinfection
option monitoring option option (proposed) option
----------------------------------------------------------------------------------------------------------------
100................................. 29.86 67.19 62.48 191.87
101-500............................. 11.23 15.02 18.95 81.38
501-1,000........................... 5.72 6.29 6.25 38.79
1,001-3,300......................... 2.99 2.91 3.39 23.45
3,301-10,000........................ 1.39 1.46 2.74 16.78
10,001-50,000....................... 0.62 0.59 0.62 4.87
50,001-100,000...................... 0.30 0.70 1.01 10.37
100,001-1,000,000................... 0.32 0.20 0.27 1.66
Average............................. 2.45 3.34 3.86 19.37
----------------------------------------------------------------------------------------------------------------
The second measure of impact is the relative total cost to
privately owned water systems compared to that incurred by publicly
owned water systems. The majority of the small systems are privately-
owned (61% of the total). As a result, privately-owned systems as a
group will have a slightly larger share of the total costs of the rule.
However, EPA has no basis for expecting cost per-system to differ
systematically with ownership.
The third measure, household costs, can also be used to gauge the
impact of a regulation and to determine whether there are
disproportionately high impacts in particular segments of the
population. Table VI-4 shows household costs by system size for each
rule component. On average, annual household costs increases
attributable to the first three rule options range from $2.45 to $3.86
(Table VI-4). For these three options, 90 percent of households will
face less than a $5 increase in annual household costs. The most
expensive option, Across-the-Board Disinfection, results in the highest
average annual household costs of $19.37. However, household costs
increase across all options for those households served by the smallest
sized systems. This occurs because they serve fewer households, and as
a result, there are fewer households to share the system's compliance
costs.
d. Macro-economic Effects
Under UMRA section 202, EPA is required to estimate the potential
macro-economic effects of the regulation. These types of effects
include those on productivity, economic growth, full employment,
creation of productive jobs, and international competitiveness. Macro-
economic effects tend to be measurable in nationwide econometric models
only if the economic impact of the regulation reaches 0.25 percent to
0.5 percent of Gross Domestic Product (GDP). In 1998, real GDP was
$7,552 billion, so a rule would have to cost at least $18 billion to
have a measurable effect. A regulation with a smaller aggregate effect
is unlikely to have any measurable impact unless it is highly focused
on a particular geographic region or economic sector. The macro-
economic effects on the national economy from the GWR should not have a
measurable effect because the total annual costs for the proposed
option range from $183 million to $199 million per year using a three
and seven percent discount rate. Even the most expensive option,
Across-the-Board Disinfection falls below the measurable threshold. The
costs are not expected to be highly focused on a particular geographic
region or sector.
[[Page 30259]]
e. Summary of EPA's Consultation With State, Local, and Tribal
Governments and Their Concerns
Consistent with the intergovernmental consultation provisions of
section 204 of UMRA, EPA has initiated consultations with the
governmental entities affected by this rule. EPA held four public
meetings for all stakeholders and three Association of State Drinking
Water Administrators early involvement meetings. Because of the GWR's
impact on small entities, the Agency convened a Small Business Advocacy
Review (SBAR) Panel in accordance with the Regulatory Flexibility Act
(RFA) as amended by the Small Business Regulatory Enforcement Fairness
Act (SBREFA) to address small entity concerns, including small local
governments specifically. EPA consulted with small entity
representatives prior to convening the Panel to get their input on the
GWR. Of the 22 small entity participants, five represented small
governments. A more detailed description of the SBREFA process can be
found in section VI.A. of this preamble. EPA also made presentations on
the GWR to the national and some local chapters of the American Water
Works Association, the Ground Water Foundation, the National Ground
Water Association, the National Rural Water Association, and the
National League of Cities. Twelve State drinking water representatives
also participated in the Agency's GWR workgroup.
In addition to these consultations, EPA circulated a draft of this
proposed rule and requested comment from the public through an informal
process. Specifically, on February 3, 1999, EPA posted on the EPA's
Internet web page and mailed out over 300 copies of the draft to people
who had attended the 1997 and 1998 public stakeholder meetings as well
as people on the EPA workgroup. EPA received 80 letters or electronic
responses to this draft: 34 from State government (representing 30
different States), 26 from local governments, ten from trade
associations, six from Federal government agencies, and four from other
people/organizations. No comments were received from tribal
governments. EPA reviewed the comments carefully and considered their
merit. Today's proposal reflects many of the commenters' points and
suggestions. For example, numerous commenters felt that proposing a
requirement to monitor source water using coliphage at this time was
premature based on currently available data. EPA has recently completed
round robin testing of coliphage methods and is requesting comment on
the use of these methods.
To inform and involve tribal governments in the rulemaking process,
EPA presented the GWR at the 16th Annual Consumer Conference of the
National Indian Health Board, at the annual conference of the National
Tribal Environmental Council, and at an EPA Office of Ground Water and
Drinking Water (OGWDW)/Inter Tribal Council of Arizona, Inc. tribal
consultation meeting. Over 900 attendees representing Tribes from
across the country attended the National Indian Health Board's Consumer
Conference and over 100 Tribes were represented at the annual
conference of the National Tribal Environmental Council. At both
conferences, an EPA representative conducted two workshops on EPA's
drinking water program and upcoming regulations, including the GWR.
Comments received from tribal governments regarding the GWR focused
on concerns and some opposition to mandatory disinfection for ground
water systems. They also suggested that any waiver process be
adequately characterized by guidance and simple to implement. EPA
agrees with concerns of Tribes and has designed the proposed GWR so
that disinfection is not mandatory. Systems will have the opportunity
to correct significant deficiencies, eliminate the source of
contamination, obtain a new source of water, or install disinfection to
achieve 4-log inactivation or removal of virus. However, some systems
in coordination with the primacy agent or State, might choose
disinfection over these other options because it may be the least
costly alternative.
At the OGWDW/Inter Tribal Council of Arizona meeting,
representatives from 15 Tribes participated. In addition, over 500
Tribes and tribal organizations were sent the presentation materials
and meeting summary. Because many Tribes have ground water systems,
participants expressed concerns over some elements of the rule.
Specifically, they had concerns about how the primacy agent would
determine significant deficiencies identified in a sanitary survey and
how the sensitivity assessment would be conducted. Because no Tribes
currently have primacy, EPA is the primacy agent and will identify
significant deficiencies as part of sanitary surveys and conduct the
hydrogeologic sensitivity assessment as outlined in section III. A. and
III.B. of this preamble.
The Agency believes the proposed option in the GWR will provide
public health benefits to individuals by reducing their exposure to
fecal contamination through targeted expenditures to address
significant deficiencies or fecal contamination. As discussed earlier
in paragraph IV.C.1.c, over 90 percent of households will incur
additional costs of less than $3.00 per month based on EPA's proposed
regulatory approach. EPA will consider other options for the final rule
as outlined in this proposal and discussed next.
f. Regulatory Alternatives Considered
As required under section 205 of the UMRA, EPA considered several
regulatory alternatives and numerous methods to identify ground water
systems most at risk to microbial contamination. A detailed discussion
of these alternatives can be found in section V of the preamble and
also in the RIA for the GWR(US EPA, 1999a). Today's proposal also seeks
comment on many regulatory options that EPA will consider for the final
rule.
g. Selection of the Least Costly, Most Cost-Effective or Least
Burdensome Alternative That Achieves the Objectives of the Rule
As discussed earlier, EPA has considered various regulatory options
that would reduce microbial contamination in ground water systems. EPA
believes that the proposed option as described in today's rule, is the
most cost effective option that achieves the rule's objective to reduce
the risk of illness and death from microbial contamination in PWS
relying on ground water. This option is a targeted approach where costs
are driven by the number of systems having to fix fecal contamination
problems and correct significant deficiencies that could lead to fecal
contamination. EPA requests comment on how possible modifications to
the proposed option, as outlined in section III of the preamble, may
affect not only the cost but also the objectives of this rule.
3. Impacts on Small Governments
In developing this rule, EPA consulted with small governments to
address impacts of regulatory requirements in the rule that might
significantly or uniquely affect small governments. In preparation for
the proposed GWR, EPA conducted an analysis on small government impacts
and included small government officials or their designated
representatives in the rulemaking process. As discussed previously, a
variety of stakeholders, including small governments, had the
opportunity for timely and meaningful participation in the regulatory
[[Page 30260]]
development process through the SBREFA process, public stakeholder
meetings, and tribal meetings. Representatives of small governments
took part in the SBREFA process for this rulemaking and they also
attended public stakeholder meetings. Through such participation and
exchange, EPA notified some potentially affected small governments of
requirements under consideration and provided officials of affected
small governments with an opportunity to have meaningful and timely
input into the development of regulatory proposals. A more detailed
discussion of the SBREFA process and stakeholder meetings can be found
in section VI.A. and section VI.C.2.e, respectively.
In addition, EPA will educate, inform, and advise small systems
including those operated by small government about GWR requirements.
One of the most important components of this process will be the Small
Entity Compliance Guide which is required by the SBREFA of 1996. This
plain-English guide will explain what actions a small entity must take
to comply with the rule. Also, the Agency is developing fact sheets
that concisely describe various aspects and requirements of the GWR.
D. National Technology Transfer and Advancement Act
Section 12(d) of the National Technology Transfer and Advancement
Act of 1995 (``NTTAA''), Pub L. No. 104-113, Sec. 12(d) (15 U.S.C. 272
note) directs EPA to use voluntary consensus standards in its
regulatory activities unless to do so would be inconsistent with
applicable law or otherwise impractical. Voluntary consensus standards
are technical standards (e.g., materials specifications, test methods,
sampling procedures, and business practices) that are developed or
adopted by voluntary consensus standards bodies. The NTTAA directs EPA
to provide Congress, through the Office of Management and Budget (OMB),
explanations when the Agency decides not to use available and
applicable voluntary consensus standards.
EPA also notes that the Agency plans to implement in the future a
performance-based measurement system (PBMS) that would allow the option
of using either performance criteria or reference methods in its
drinking water regulatory programs. The Agency is determining the
specific steps necessary to implement PBMS in its programs. Final
decisions have not yet been made concerning the implementation of PBMS
in water programs. However, EPA is evaluating what relevant performance
characteristics should be specified for monitoring methods used in the
water programs under a PBMS approach to ensure adequate data quality.
EPA would then specify performance requirements in its regulations to
ensure that any method used for determination of a regulated analyte is
at least equivalent to the performance achieved by other currently
approved methods.
Once EPA has made its final determinations regarding implementation
of PBMS in programs under the Safe Drinking Water Act, EPA would
incorporate specific provisions of PBMS into its regulations, which may
include specification of the performance characteristics for
measurement of regulated contaminants in the drinking water program
regulations.
1. Microbial Monitoring Methods
The proposed rulemaking involves technical standards. Ground water
systems that are identified by the State as having hydrogeologically
sensitive wells as described in Secs. 142.16(k)(3) and 141.403(a), and
ground water systems that have a TCR positive sample as described in
Sec. 141.403(b) of today's proposed rule must sample and test their
source water. GWSs must test for at least one of the following fecal
indicators: E. coli, enterococci and coliphage using one of the methods
in Sec. 141.403(d) and discussed in greater detail in III.D.4. Table
VI-5 lists the microbial methods which must be used for source water
monitoring.
EPA proposes to use several approved methods. For testing E. coli
and enterococci, the methods in Sec. 141.403(d) are either consensus
methods or new methods that EPA has recently approved for drinking
water monitoring with the exception of Enterolert (a method for
enterococci) for which EPA is proposing approval through this
rulemaking. EPA is also proposing testing source waters for the
presence for coliphage. EPA proposes to use EPA Method 1601: Two-Step
Enrichment Presence-Absence Procedure and EPA Method 1602: Single Agar
layer Procedure.
While the Agency identified Standards Methods, Method 9211D
Coliphage Detection (20th edition of Standard Methods for the
Examination of Water and Wastewater) as being potentially applicable,
EPA does not propose to use it in this rulemaking. The use of this
voluntary consensus standard would not meet the Agency's needs because
the method does not detect male specific coliphage, the sample volume
is inappropriately small (20 ml versus the GWR's proposed 100 ml sample
requirement), and according to the method, the sensitivity may not be
high enough to detect one coliphage in a 100 ml sample. EPA welcomes
comments on this aspect of the proposed rulemaking and, specifically,
invites the public to identify potentially-applicable voluntary
consensus standards and to explain why such standards should be used in
this regulation.
Table VI-5.--Microbial Methods
------------------------------------------------------------------------
Analytical methods for source water monitoring
-------------------------------------------------------------------------
Indicator Method\1\
------------------------------------------------------------------------
E. coli................................ Colilert Test (Method 9223B)
\2\ \3\
Colisure Test (Method 9223B)
\2\ \3\
Membrane Filter Method with MI
Agar \4\ \5\
m-ColiBlue24 Test \4\ \6\
E*Colite Test \4\ \7\
May also use the EC-MUG (Method
9212F) \2\ and NA-MUG (Method
9222G) \2\ E. coli
confirmation step Sec.
141.21(f)(6) after the EPA
approved Total Coliform
methods in Sec. 141.21(f)(3)
enterococci............................ Multiple-Tube Tech. (Method
9230B) \1\
Membrane Filter Tech. (Method
9230C) \1\ \8\
Enterolert \3\
Coliphage.............................. EPA Method 1601: Two-Step
Enrichment Presence-Absence
Procedure \9\
EPA Method 1602: Single Agar
layer Procedure \9\
------------------------------------------------------------------------
\1\ The time from sample collection to initiation of analysis may not
exceed 30 hours. Systems are encouraged but not required to hold
samples below 10 deg.C during transit.
\2\ Methods are approved and described in Standard Methods for the
Examination of Water and Wastewater (20th edition).
\3\ Medium available through IDEXX Laboratories, Inc., One IDEXX Drive,
Westbrook, Maine 04092.
\4\ EPA approved drinking water methods.
\5\ Brenner, K.P., C.C. Rankin, Y.R. Roybal, G.N. Stelma, P.V. Scarpino,
and A.P. Dufour. 1993. New medium for the simultaneous detection of
total coliforms and Escherichia coli in water. Appl. Environ.
Microbiol. 59:3534-3544.
\6\ Hach Company, 100 Dayton Ave., Ames, IA 50010.
\7\ Charm Sciences, Inc., 36 Franklin St., Malden, MA 02148-4120.
\8\ Proposed for EPA approval, EPA Method 1600: MF Test Method for
enterococci in Water (EPA-821-R-97-004 (May 1997)) is an approved
variation of Standard Method 9230C.
\9\ Proposed for EPA approval are EPA Methods 1601 and 1602, which are
available from the EPA's Water Resources Center, Mail code: RC-4100,
1200 Pennsylvania Ave. NW, Washington, DC 20460.
[[Page 30261]]
E. Executive Order 12866: Regulatory Planning and Review
Under Executive Order 12866, (58 FR 51,735,October 4,1993) the
Agency must determine whether the regulatory action is ``significant''
and therefore subject to OMB review and the requirements of the
Executive Order. The Order defines ``significant regulatory action'' as
one that is likely to result in a rule that may: (1) Have an annual
effect on the economy of $100 million or more or adversely affect in a
material way the economy, a sector of the economy, productivity,
competition, jobs, the environment, public health or safety, or State,
local, or tribal governments or communities; (2) create a serious
inconsistency or otherwise interfere with an action taken or planned by
another agency; (3) materially alter the budgetary impact of
entitlement, grants, user fees, or loan programs or the rights and
obligations of recipients thereof; or (4) raise novel legal or policy
issues arising out of legal mandates, the President's priorities, or
the principles set forth in the Executive Order.
Pursuant to the terms of Executive Order 12866, EPA has determined
that this rule is a ``significant regulatory action''. As such, this
action was submitted to OMB for review. Changes made in response to OMB
suggestions or recommendations are documented in the public record.
F. Executive Order 12898: Environmental Justice
Executive Order 12898 establishes a Federal policy for
incorporating environmental justice into Federal agency missions by
directing agencies to identify and address disproportionately high and
adverse human health or environmental effects of its programs,
policies, and activities on minority and low-income populations. The
Agency has considered environmental justice issues concerning the
potential impacts of this action and has consulted with minority and
low-income stakeholders.
The Environmental Justice Executive Order requires the Agency to
consider environmental justice issues in the rulemaking and to consult
with minority and low-income stakeholders. There are two aspects of
today's proposed rule that relate specifically to this policy: the
overall nature of the rule, and the convening of a stakeholder meeting
specifically to address environmental justice issues. The GWR applies
to all public water systems: community water systems, nontransient
noncommunity water systems, and transient noncommunity water systems
that use ground water as their source water. Consequently, the health
protection benefits provided by this proposal are equal across all
income and minority groups served by these systems. Existing
regulations such as the SWTR and IESWTR provide similar health benefit
protection to communities that use surface water or ground water under
the direct influence of surface water.
As part of EPA's responsibilities to comply with Executive Order
12898, the Agency held a stakeholder meeting on March 12, 1998 to
address various components of pending drinking water regulations; and
how they may impact sensitive sub-populations, minority populations,
and low-income populations. Topics discussed included treatment
techniques, costs and benefits, data quality, health effects, and the
regulatory process. Participants included national, State, tribal,
municipal, and individual stakeholders. EPA conducted the meetings by
video conference call with participants in eleven cities. This meeting
was a continuation of stakeholder meetings that started in 1995 to
obtain input on the Agency's drinking water programs. The major
objectives for the March 12, 1998 meeting were: solicit ideas from
environmental justice (EJ) stakeholders on known issues concerning
current drinking water regulatory efforts; identify key issues of
concern to EJ stakeholders; and receive suggestions from EJ
stakeholders concerning ways to increase representation of EJ
communities in EPA's Office of Water regulatory efforts. In addition,
EPA developed a plain-English guide specifically for this meeting to
assist stakeholders in understanding the multiple and sometimes complex
drinking water issues.
G. Executive Order 13045: Protection of Children from Environmental
Health Risks and Safety Risks
Executive Order 13045: ``Protection of Children from Environmental
Health Risks and Safety Risks'' (62 FR 19885, April 23, 1997) applies
to any rule that: (1) Is determined ``economically significant'' as
defined under Executive Order 12866, and (2) concerns an environmental
health or safety risk that EPA has reason to believe may have a
disproportionate effect on children. If the regulatory action meets
both criteria, the Agency must evaluate the environmental health or
safety effects of the planned rule on children, and explain why the
planned regulation is preferable to other potentially effective and
reasonably feasible alternatives considered by the Agency.
This proposed rule is subject to this Executive Order because it is
an economically significant regulatory action as defined by Executive
Order 12866, and EPA believes that the environmental health or safety
risk addressed by this action may have a disproportionate effect on
children. Accordingly, EPA has evaluated the environmental health or
safety effects of viruses on children. The results of this evaluation
are contained in section II.E. of the preamble and in the RIA for
today's rule (US EPA, 1999a). A copy of RIA and its supporting
documents have been placed in the Office of Water docket for this
proposal.
1. Risk of Viral Illness to Children and Pregnant Women
The risk of illness and death due to viral contamination of
drinking water depends on several factors, including the age and the
immune status of the exposed individual. Two groups that are at
increased risk of illness and mortality due to waterborne pathogens are
children and pregnant women (Gerba et al., 1996). For example,
rotavirus infections can occur in people of all ages, however they
primarily affect young children (US EPA, 1999b). Infants and young
children have higher rates of infection and disease from enteroviruses
than other age groups (US EPA, 1999b). Several viruses that can be
transmitted through water can have serious health consequences in
children. Enteroviruses (which include poliovirus, coxsackievirus and
echovirus) have been implicated in cases of paralytic polio, heart
disease, encephalitis, hemorrhagic conjunctivitis, hand-foot-and-mouth
disease and diabetes mellitis (CDC, 1997; Modlin, 1997; Melnick, 1996;
Cherry, 1995; Berlin and Rorabaugh, 1993; Smith, 1970; Dalldorf and
Melnick, 1965). Women may be at increased risk from enteric viruses
during pregnancy (Gerba et al., 1996). Enterovirus infections in
pregnant women can also be transmitted to the unborn child late in
pregnancy, sometimes resulting in severe illness in the newborn (US
EPA, 1999c). Coxsackievirus and echovirus may be transmitted from the
mother to the child in utero (Gerba et al., 1996).
To comply with Executive Order 13045, EPA calculated the baseline
risk (e.g., risk without this rule) and with-rule reduction of risk
from waterborne illness and mortality for children. To address the
disproportionate risk of waterborne illness and mortality to children
under this rulemaking, EPA applied age-specific parameters regarding
morbidity to the risk assessment. The risk assessment first
[[Page 30262]]
extracted the proportion of the population that falls into several age
categories that may be more or less susceptible to waterborne viral
illness than the general population. The extraction was done separately
for two model viruses. Bacterial illnesses are not addressed in this
analysis, however, EPA estimates that bacterial illnesses account for
an additional 20% of viral illnesses.
When assessing the risk of illness due to viruses of low-to-medium
infectivity (using echovirus as a surrogate), the age categories used
were less than one month of age, one month to five years of age, five
to sixteen years of age and greater than sixteen years of age. It was
assumed that 50% of children less than five years old would become ill
once infected with low-to-medium infectivity viruses; while 57% of
children five years to sixteen years of age and 33% of people over
sixteen would become ill once infected. This estimate was based on a
community-wide echovirus type 30 epidemic (Hall, 1970). See Appendix A
of the RIA.
When assessing the risk of illness due to viruses of high
infectivity (using rotavirus as a surrogate) the age categories used
were less than two years of age, two to five years of age, five to
sixteen years old and greater than sixteen years old. It was assumed
that 88% of children less than two years old would become ill once
infected with high infectivity viruses; while 40% was assumed for
everyone else. The morbidity rates for high infectivity viruses were
based on data from Kapikian and Chanock (1996) for children less than
two. For other age categories, EPA has conservatively estimated a
morbidity of 10 based upon studies of rotavirus illness in households
with newborn children (Wenman et al., 1979) and of an outbreak in an
isolated community (Foster et. al., 1980). See Appendix A of the RIA.
In addition to illness, EPA also considered child mortality
attributable to waterborne microbial illness. For low-to-medium
infectivity viruses, 0.92% of children less than one month of age who
become ill were assumed to die based on information from Jenista et
al., (1984) and Modlin (1986), while .041% of people greater than one
month old who become ill were assumed to die. For viruses of high
infectivity, 0.00073% of infected children less than four years old
were assumed to die (Tucker et al., 1998). The low-to-medium
infectivity viruses result in a higher mortality rate than the high
infectivity viruses because the low-to-medium infectivity viruses cause
more serious health effects.
The proposed GWR specifically targets systems with existing or
potential fecal contamination, including viral contamination. To
estimate the benefits to children from today's proposed rule, the
Agency calculated the number of illnesses and deaths avoided by the
rule for the children less than 5 years old and for children between
the ages of 5 and 16. Table VI-6 presents a summary of these estimates.
Overall, the proposed rule would result in 26,566 less illnesses caused
by viruses per year occurring in children 16 years of age and less. The
proposed rule is also expected to result in 2 less deaths per year due
to viral illness among children aged 16 or less.
Table VI-6.--Reductions of Viral Illness and Death in Children Resulting from Various Regulatory Approaches
----------------------------------------------------------------------------------------------------------------
Illness reduction Death reduction Illness reduction Death reduction
Options (ages 0-5) (ages 0-5) (5-16 years old) (5-16 years old)
----------------------------------------------------------------------------------------------------------------
Sanitary Survey Only............ 2,292 0 1,773 0
Sanitary Survey and Triggered 13,044 1 9,974 1
Monitoring.....................
Multi-barrier (Proposed)........ 15,058 1 11,508 1
Across-the-board Disinfection... 21,125 1 16,059 2
----------------------------------------------------------------------------------------------------------------
The Agency believes the proposed multi-barrier approach will
provide the most cost-effective method of reducing viral and bacterial
illness in children that results from contaminated ground water. The
proposed option will reduce 3,500 more cases of viral illness in
children each year than the sanitary survey and triggered monitoring
option. This additional reduction is obtained with only a slightly
larger increase in total annual costs. Conversely, the additional
reductions in illness gained with the across-the-board option comes at
a much higher cost. It is estimated that the across-the-board option
will cost approximately $12,000 more per case of illness avoided than
the multi-barrier approach.
2. Full Analysis of the Microbial Risk Assessment
A full analysis of the microbial risk assessment is provided in the
Appendix to the RIA for the proposed GWR, and a summary is provided in
this preamble (see section II.E.).
The public is invited to submit or identify peer-reviewed studies
and data, of which EPA may not be aware, that assessed results of early
life exposure to viruses and bacteria.
H. Consultations with the Science Advisory Board, National Drinking
Water Advisory Council, and the Secretary of Health and Human Services
In accordance with section 1412 (d) and (e) of the SDWA, the Agency
did consult with the Science Advisory Board and will request comment
from the National Drinking Water Advisory Council (NDWAC) and the
Secretary of Health and Human Services on the proposed rule.
I. Executive Order on Federalism
Executive Order 13132, entitled ``Federalism'' (64 FR 43255, August
10, 1999), requires EPA to develop an accountable process to ensure
``meaningful and timely input by State and local officials in the
development of regulatory policies that have Federalism implications''.
``Policies that have Federalism implications'' is defined in the
Executive Order to include regulations that have ``substantial direct
effects on the States, on the relationship between the national
government and the States, or on the distribution of power and
responsibilities among the various levels of government''. Under
section 6 of Executive Order 13132, EPA may not issue a regulation that
has Federalism implications, that imposes substantial direct compliance
costs, and that is not required by statute, unless the Federal
government provides the funds necessary to pay the direct compliance
costs incurred by State and local governments, or EPA consults with
State and local officials early in the process of developing the
proposed regulation. EPA also may not issue a regulation that has
Federalism implications and that preempts State
[[Page 30263]]
law, unless the Agency consults with State and local officials early in
the process of developing the proposed regulation.
If EPA complies by consulting, Executive Order 13132 requires EPA
to provide to the Office of Management and Budget (OMB), in a
separately identified section of the preamble to the final rule, a
Federalism summary impact statement (FSIS). The FSIS must include a
description of the extent of EPA's prior consultation with State and
local officials, a summary of the nature of their concerns and the
Agency's position supporting the need to issue the regulation, and a
statement of the extent to which the concerns of State and local
officials have been met. Also, when EPA transmits a draft final rule
with Federalism implications to OMB for review pursuant to Executive
Order 12866, EPA must include a certification from the Agency's
Federalism Official stating that EPA has met the requirements of
Executive Order 13132 in a meaningful and timely manner.
EPA has concluded that this proposed rule may have Federalism
implications since it may impose substantial direct compliance costs on
local governments, and the Federal government will not provide the
funds necessary to pay those cost. Accordingly, EPA provides the
following FSIS as required by section 6(b) of Executive Order 13132.
As discussed in section I.A., EPA met with a variety of State and
local representatives including several local elected officials, who
provided meaningful and timely input in the development of the proposed
rule. Summaries of the meetings have been included in the public record
for this proposed rulemaking. EPA consulted extensively with State,
local, and tribal governments. For example, four public stakeholder
meetings were held in Washington, DC, Portland, Oregon, Madison
Wisconsin and Dallas, Texas. EPA also held three early involvement
meetings with the Association of State Drinking Water Administrators.
Several key issues were raised by stakeholders regarding the GWR
provisions, many of which were related to reducing burden and
maintaining flexibility. The Office of Water was able to reduce burden
and increase flexibility by creating a targeted risk based approach
which builds upon existing State programs. It should be noted that this
rule is important because it will reduce the incidence of fecally
contaminated drinking water supplies by requiring corrective actions
for fecally contaminated systems or systems with a significant risk of
fecal contamination resulting in a reduced waterborne illness. Because
consultation on this proposed rule occurred before the November 2,
1999, effective date of Executive Order 13132, EPA will initiate
discussions with State and local elected officials regarding the
implications of this rule during the public comment period.
J. Executive Order 13084: Consultation and Coordination With Indian
Tribal Governments
Under Executive Order 13084, EPA may not issue a regulation that is
not required by statute, that significantly or uniquely affects the
communities of Indian tribal governments, and that imposes substantial
direct compliance costs on those communities, unless the Federal
government provides the funds necessary to pay the direct compliance
costs incurred by the tribal governments, or EPA consults with those
governments. If EPA complies by consulting, Executive Order 13084
requires EPA to provide to the OMB, in a separately identified section
of the preamble to the rule, a description of the extent of EPA's prior
consultation with representatives of affected tribal governments, a
summary of the nature of their concerns, and a statement supporting the
need to issue the regulation. In addition, Executive Order 13084
requires EPA to develop an effective process permitting elected
officials and other representatives of Indian tribal governments ``to
provide meaningful and timely input in the development of regulatory
policies on matters that significantly or uniquely affect their
communities.''
EPA has concluded that this rule will significantly affect
communities of Indian tribal governments because 92 percent of PWSs in
Indian Country are ground water systems. It will also impose
substantial direct compliance costs on such communities, and the
Federal government will not provide the funds necessary to pay the
direct costs incurred by the tribal governments in complying with the
rule. In developing this rule, EPA consulted with representatives of
tribal governments pursuant to Executive Order 13084. EPA's
consultation, the nature of the tribal governments' concerns, and EPA's
position supporting the need for this rule are discussed in section
VI.C. which addresses compliance with UMRA.
As described in section VI.C.2.e. of the UMRA discussion, EPA held
extensive public meetings that provided the opportunity for meaningful
and timely input in the development of the proposed rule. Summaries of
the meetings have been included in the Office of Water public docket
for this rulemaking. In addition, the Agency presented the rule and
asked for comment at three tribal conferences. Two consultations took
place at national conferences; one for the National Indian Health Board
and the other for the National Tribal Environmental Council. The third
consultation was conducted in conjunction with the Inter-Tribal Council
of Arizona, Inc. A more detailed discussion of these consultations can
be found in the UMRA consultation section (section VI.C.2.c.).
K. Plain Language
Executive Order 12866 and the President's memorandum of June 1,
1998, require each agency to write its rules in plain language. EPA
invites comments on how to make this proposed rule easier to
understand. For example: Has EPA organized the material to suit
commenters' needs? Are the requirements in the rule clearly stated?
Does the rule contain technical language or jargon that is not clear?
Would a different format (grouping and order of sections, use of
headings, paragraphs) make the rule easier to understand? Would shorter
sections make this rule easier to understand? Could EPA improve clarity
by adding tables, lists, or diagrams? What else could EPA do to make
the rule easier to understand?
VII. Public Comment Procedures
EPA invites you to provide your views on this proposal, approaches
we have not considered, the potential impacts of the various options
(including possible unintended consequences), and any data or
information that you would like the Agency to consider. Many of the
sections within today's proposed rule contain ``Request for Comment''
portions which the Agency is also interested in receiving comment on.
A. Deadlines for Comment
Send your comments on or before July 10, 2000. Comments received
after this date may not be considered in decision making on the
proposed rule.
B. Where To Send Comment
Send an original and 3 copies of your comments and enclosures
(including references) to W-98-23 Comment Clerk, Water Docket (MC4101),
USEPA, 1200 Pennsylvania Ave., NW, Washington DC 20460. Hand deliveries
should be delivered to the Comment Clerk, Water Docket (MC4101), USEPA
401 M , Washington, D.C. 20460. Comments may also be submitted
electronically to [email protected]. Electronic comments must
be submitted as an
[[Page 30264]]
ASCII, WP5.1, WP6.1 or WP8 file avoiding the use of special characters
and form of encryption. Electronic comments must be identified by the
docket number W-98-23. Comments and data will also be accepted on disks
in WP 5.1, 6.1, 8 or ASCII file format. Electronic comments on this
notice may be filed online at many Federal Depository Libraries. Those
who comment and want EPA to acknowledge receipt of their comments must
enclose a self-addressed stamped envelope. No facsimiles (faxes) will
be accepted. Comments may also be submitted electronically to [email protected].
C. Guidelines for Commenting
To ensure that EPA can read, understand and therefore properly
respond to comments, the Agency would prefer that commenters cite,
where possible, the paragraph(s) or sections in the notice or
supporting documents to which each comment refers. Commenters should
use a separate paragraph for each issue discussed. Note that the Agency
is not soliciting comment on, nor will it respond to, comments on
previously published regulatory language that is included in this
notice to ease the reader's understanding of proposed language. You may
find the following suggestions helpful for preparing your comments:
1. Explain your views as clearly as possible.
2. Describe any assumptions that you used.
3. Provide technical information and/or data to support your views.
4. If you estimate potential burden or costs, explain how you
arrived at the estimate.
5. Indicate what you support, as well as what you disagree with.
6. Provide specific examples to illustrate your concerns.
7. Make sure to submit your comments by the deadline in this
proposed rule.
8. At the beginning of your comments (e.g., as part of the
``Subject'' heading), be sure to properly identify the document you are
commenting on. You can do this by providing the docket control number
assigned to the proposed rule, along with the name, date, and Federal
Register citation.
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populations: who is at the greatest risk? Int. J. Food Micro.
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Haas, C.N. and J.B. Rose. 1995. Developing an action level for
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List of Subjects in 40 CFR Parts 141 and 142
Environmental protection, Indians-lands, Intergovernmental
relations, Radiation protection, Reporting and recordkeeping
requirements, Water.
Dated: April 17, 2000.
Carol M. Browner,
Administrator.
For the reasons set forth in the preamble, title 40 chapter I of
the Code of Federal Regulations is proposed to be amended as follows:
PART 141--NATIONAL PRIMARY DRINKING WATER REGULATIONS
1. The authority citation for part 141 continues to read as
follows:
Authority: 42 U.S.C. 300f, 300g-1, 300g-2, 300g-3, 300g-4, 300g-
5, 300g-6, 300j-4, 300j-9, and 300j-11.
2. Section 141.21 is amended by adding paragraph (d)(3) to read as
follows:
Sec. 141.21 Coliform sampling.
* * * * *
(d) * * *
(3) Sanitary surveys conducted by the State under Sec. 142.16(k)(2)
of this chapter, at the frequencies specified, may be used to meet the
sanitary surveys requirements of this section.
* * * * *
3. Section 141.154 is amended by adding paragraph (f) to read as
follows:
Sec. 141.154 Required additional health information.
* * * * *
(f) Ground water systems that detect E. coli, enterococci or
coliphage in the source water as required by Sec. 141.403 must include
the health effects language prescribed by Appendix B of subpart Q of
this part.
* * * * *
4. Section 141.202 as added by the final rule published on May 4,
2000 is amended by adding entry (9) in numerical order to the table in
paragraph (a) to read as follows:
Sec. 141.202 Tier 1 Public Notice--Form, manner, and frequency of
notice.
(a) * * *
------------------------------------------------------------------------
Table 1 to Sec. 141.202--violation categories and other situations
requiring a tier 1 public notice
-------------------------------------------------------------------------
* * * * *
(9) Violation of the treatment technique for the Ground Water Rule (as
specified in Sec. 141.405(a) through (c) or when E. coli,
enterococci, or coliphage are present as specified in Sec. 141.403)
or when the water system fails to test for E. coli, enterococci,
coliphage (as specified in Sec. 141.403).
* * * * *
------------------------------------------------------------------------
5. Appendix A of subpart Q as added by the final rule published on
May 4, 2000 is amended by adding entry 8. under I.A. ``Microbiological
Contaminants'' and by adding entry G. under IV. ``Other Situations
Requiring Public Notification'' to read as follows:
[[Page 30268]]
Appendix A to Subpart Q of Part 141.--NPDWR Violations and Other Situations Requiring Public Notice \1\
(Including D/DBP and IESWTR Violations)
----------------------------------------------------------------------------------------------------------------
MCL/MRDL/TT violations Monitoring and testing
\2\ procedure violations
---------------------------------------------------
Contaminant Tier of Tier of
public public
notice Citation notice Citation
required required
----------------------------------------------------------------------------------------------------------------
* * * * * *
*
A. Microbiological Contaminants
----------------------------------------------------------------------------------------------------------------
* * * * * *
*
8. GWR TT violations........................................ 1 141.405 N/A N/A
* * * * * *
*
IV. Other Situations Requiring Public Notification
----------------------------------------------------------------------------------------------------------------
* * * * * *
*
----------------------------------------------------------------------------------------------------------------
G. Fecal indicators for GWR: E. coli, enterococci, coliphage 1 141.403 1 141.403
----------------------------------------------------------------------------------------------------------------
Appendix A Endnotes
\1\ Violations and other situations not listed in this table (e.g., reporting violations and failure to prepare
Consumer Confidence Reports), do not require notice, unless otherwise determined by the primacy agency.
Primacy agencies may, at their option, also require a more stringent public notice tier (e.g., Tier 1 instead
of Tier 2 or Tier 2 instead of Tier 3) for specific violations and situations listed in this Appendix, as
authorized under Sec. &141.202(a) and Sec. 141.203(a).
\2\ MCL--Maximum contaminant level, MRDL-Maximum residual disinfectant level, TT--Treatment technique.
* * * * *
6. Appendix B to subpart Q as added by the final rule published on
May 4, 2000 is amended by adding a new entry 1c in numerical order un
A. ``Microbiological Contaminants'' and by redisinating entries C.
through H. as D. through I. and adding a new C. in alphabetical order
to read as follows:
Appendix B of Subpart Q of Part 141.--Standard Health Effects Language for Public Notification
--------------------------------------------------------------------------------------------------------------------------------------------------------
Standard
health
effects
Contaminant MCLG \1\ mg/L MCL \2\ mg/L language for
public
notification
-------------------------------------------------------------------------------------------------------------------------------------------- --------------
* * * * * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------
A. Microbiological Contaminants
--------------------------------------------------------------------------------------------------------------------------------------------------------
* * * * * * *
1c. Fecal indicators (GWR):
i. E. coli....................... Zero..................... None.................... Fecal indicators are bacteria or viruses whose
ii. enterococci.................. None..................... presence indicates that the water may be
iii. coliphage................... None..................... contaminated with human or animal wastes.
Microbes in these wastes can cause short-term
effects, such as diarrhea, cramps, nausea,
headaches, or other symptoms. They may pose a
special health risk for infants, young
children, some of the elderly, and people with
severely compromised immune systems
* * * * * * *
C. Ground Water Rule (GWR) TT None..................... TT...................... Inadequately treated or inadequately protected
violations. water may contain disease-causing organisms.
These organisms include bacteria and viruses
which can cause symptoms such as diarrhea,
nausea, cramps, and associated headaches.
* * * * * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------
Appendix B Endnotes
1. MCLG--Maximum contaminant level goal.
2. MCL--Maximum contaminant level.
[[Page 30269]]
* * * * *
7. Appendix C to subpart Q as added in the final rule published on
May 4, 2000 amended by adding the following abbreviation in
alphabetical order to read as follow:
Appendix C to Subpart Q of Part 141--List of Acronyms Used in Public
Notification Regulation
* * * * *
GWR Ground Water Rule
* * * * *
9. A new subpart S is proposed to be added to read as follows:
Subpart S--Ground Water Rule
Sec.
141.400 General requirements and applicability.
141.401 Sanitary survey information request.
141.402 Hydrogeologic sensitivity assessment information request.
141.403 Microbial monitoring of source water and analytical
methods.
141.404 Treatment technique requirements.
141.405 Treatment technique violations.
141.406 Reporting and record keeping.
Subpart S--Ground Water Rule
Sec. 141.400 General requirements and applicability.
(a) Scope of this subpart. The requirements of this subpart S
constitute national primary drinking water regulations.
(b) Applicability. All public water systems that are served solely
by ground water. The requirements in this subpart also apply to subpart
H systems that distribute ground water that is not treated to 4-log
inactivation or removal of viruses before entry into the distribution
system. Systems supplied by ground water under the direct influence of
surface water are regulated under subparts H and P of this part, not
under this subpart. For the purposes of this subpart, ``ground water
system'' is defined as any public water system meeting this
applicability statement.
(c) General requirements. These regulations in this subpart
establish requirements related to sanitary surveys, hydrogeologic
sensitivity assessments, and source water microbial monitoring
performed at ground water systems as defined by paragraph (b) of this
section. The regulations in this subpart also establish treatment
technique requirements for these ground water systems which have
fecally contaminated source waters, as demonstrated under Sec. 141.403,
or significant deficiencies as identified in a sanitary survey
conducted by a State under either Sec. 142.16(k)(2) of this chapter or
by EPA under SDWA section 1445. Ground water systems with fecally
contaminated source water or significant deficiencies must meet one or
more of the following treatment technique requirements: eliminate the
source of contamination, correct the significant deficiency, provide an
alternate source water, or provide a treatment which reliably achieves
at least 99.99 percent (4-log) inactivation or removal of viruses
before or at the first customer. Ground water systems which provide 4-
log inactivation or removal of viruses will be required to conduct
compliance monitoring to demonstrate treatment effectiveness.
(d) Compliance dates. Ground water systems must comply with the
requirements of this subpart beginning [DATE 3 YEARS AFTER PUBLICATION
OF THE FINAL RULE IN THE FEDERAL REGISTER.
Sec. 141.401 Sanitary survey information request.
Ground water systems must provide the State at its request, any
pertinent existing information that would allow the State to perform a
sanitary survey as described in Sec. 142.16(k)(2) of this chapter. For
the purposes of this subpart, ``sanitary survey,'' as conducted by the
State, includes but is not limited to an onsite review of the water
source (identifying sources of contamination by using results of source
water assessments or other relevant information where available),
facilities, equipment, operation, maintenance, and monitoring
compliance of a public water system to evaluate the adequacy of the
system, its sources and operations and the distribution of safe
drinking water.
Sec. 141.402 Hydrogeologic sensitivity assessment information request.
Ground water systems must provide the State at its request, any
pertinent existing information that would allow the State to perform a
hydrogeologic sensitivity assessment as described in Sec. 142.16(k)(3)
of this chapter.
Sec. 141.403 Microbial monitoring of source water and analytical
methods.
(a) Routine monitoring. Any ground water system that draws water
from a hydrogeologically sensitive drinking water source, as determined
under Sec. 142.16(k)(3) of this chapter, and that does not provide 4-
log inactivation or removal of viruses, must collect a source water
sample each month that it provides water to the public and test the
sample for the fecal indicator specified by the State under paragraph
(d) of this section. Ground water systems must begin monitoring the
month after being notified of the hydrogeologic sensitivity assessment.
(b) Triggered monitoring. Any ground water system that does not
provide 4-log inactivation or removal of viruses, and is notified of a
total coliform-positive sample under Sec. 141.21, must collect, within
24 hours of notification, at least one source water sample and have the
sample tested for the fecal indicator specified by the State under
paragraph (d) of this section. This requirement is in addition to all
monitoring and testing requirements under Sec. 141.21.
(c) Systems with disinfection. Ground water systems currently
providing 4-log inactivation or removal of viruses must notify the
State of such and must conduct compliance monitoring in accordance with
Sec. 141.404(c). This notification must be made by the effective date
of the rule. All new systems must notify the State of the level of
virus inactivation they are achieving prior to serving their first
customer.
(d) Analytical methods. Source water samples must be tested for one
of the following fecal indicators: E. coli, coliphage, or enterococci,
as specified by the State. For whichever fecal indicator is specified
by the State, the ground water system must use one of the analytical
methods listed in the following table:
Analytical Methods for Source Water Monitoring
------------------------------------------------------------------------
Indicator Method\1\
------------------------------------------------------------------------
E. coli................................ Colilert Test (Method
9223B)\2,\ \3\
Colisure Test (Method
9223B)\2,\ \3\
Membrane Filter Method with MI
Agar\4,\ \5\
m-ColiBlue24 Test \4,\ \6\
E*Colite Test \4,\ \7\
May also use the EC-MUG (Method
9212F) \2\ and NA-MUG (Method
9222G) \2\ E. coli
confirmation step Sec.
141.21(f)(6) after the EPA
approved Total Coliform
methods in Sec. 141.21(f)(3)
enterococci............................ Multiple-Tube Tech. (Method
9230B) \1\
Membrane Filter Tech. (Method
9230C) \1,\ \8\
Enterolert \3\
Coliphage.............................. EPA Method 1601: Two-Step
Enrichment Presence-Absence
Procedure\9\
EPA Method 1602: Single Agar
layer Procedure\9\
------------------------------------------------------------------------
\1\ The time from sample collection to initiation of analysis may not
exceed 30 hours. Systems are encouraged but not required to hold
samples below 10 deg.C during transit.
\2\ Methods are approved and described in Standard Methods for the
Examination of Water and Wastewater (20th edition).
[[Page 30270]]
\3\ Medium available through IDEXX Laboratories, Inc., One IDEXX Drive,
Westbrook, Maine 04092.
\4\ EPA approved drinking water methods.
\5\ Brenner, K.P., C.C. Rankin, Y.R. Roybal, G.N. Stelma, P.V. Scarpino,
and A.P. Dufour. 1993. New medium for the simultaneous detection of
total coliforms and Escherichia coli in water. Appl. Environ.
Microbiol. 59:3534-3544.
\6\ Hach Company, 100 Dayton Ave., Ames, IA 50010.
\7\ Charm Sciences, Inc., 36 Franklin St., Malden, MA 02148-4120.
\8\ Proposed for EPA approval, EPA Method 1600: MF Test Method for
enterococci in Water (EPA-821-R-97-004 (May 1997)) is an approved
variation of Standard Method 9230C.
\9\ Proposed for EPA approval are EPA Methods 1601 and 1602, which are
available from the EPA's Water Resources Center, Mail code: RC-4100,
1200 Pennsylvania Ave. NW, Washington, DC 20460.
(e) Notification of State. If any source water sample is positive
for E. coli, coliphage, or enterococci, the ground water system shall
notify the State as soon as possible after the system is notified of
the test result, but in no case later than the end of the next business
day, and take corrective action in accordance with Sec. 141.404(b).
(f) Resampling after invalidation. Where the State invalidates a
positive source water sample under paragraph (i) of this section, the
ground water system must collect another source water sample and have
it analyzed for the same fecal indicator within 24 hours of being
notified of the invalidation.
(g) Triggered monitoring waiver. The State may waive triggered
source water monitoring as described in Sec. 141.403(b) due to a total
coliform-positive sample, on a case-by-case basis, if the State
determines that the total coliform positive sample is associated solely
with a demonstrated distribution system problem. In such a case, a
State official must document the decision, including the rationale for
the decision, in writing, and sign the document.
(h) Reduce frequency for routine monitoring. The State may reduce
routine source water monitoring to quarterly if a hydrogeologically
sensitive ground water system detects no fecal indicator-positive
samples in the most recent twelve monthly samples, during the months
the ground water system is in operation. Moreover, the State may, after
those twelve monthly samples, waive source water monitoring altogether
for a ground water system if the State determines, and documents the
determination in writing, that fecal contamination of the well(s) has
not been identified and is highly unlikely based on the sampling
history, land use pattern, disposal practices in the recharge area, and
proximity of septic tanks and other fecal contamination sources. If the
State determines that circumstances have changed, the State has the
discretion to reinstate routine monthly monitoring. In any case, a
State official must document the determination in writing, including
the rationale for the determination, addressing each factor noted in
this paragraph and sign the document.
(i) Invalidation of samples. A source water sample may be
determined by the State to be invalid only if the laboratory
establishes that improper sample analysis occurred or the State has
substantial grounds to believe that a sample result is due to
circumstances that do not reflect source water quality. In such a case,
a State official must document the decision, including the rationale
for the decision, in writing, and sign the document. The written
documentation must state the specific cause of the invalid sample and
what action the ground water system or laboratory has taken or will
take to correct this problem. A positive sample may not be invalidated
by the State solely on the grounds that repeat samples are negative.
(j) Repeat sampling. A ground water system may apply to the State,
and the State may consider, on a one-time basis, to waive compliance
with the treatment technique requirements in Sec. 141.404(b), after a
single fecal indicator-positive from a routine source water sample as
required in Sec. 141.403(a), if all the following conditions are met:
(1) The ground water system collects five repeat source water
samples within 24 hours after being notified of a source water fecal
indicator positive result;
(2) The ground water system has the samples analyzed for the same
fecal indicator as the original sample;
(3) All the repeat samples are fecal indicator negative; and
(4) All required source water samples (routine and triggered)
during the past five years were fecal indicator-negative.
Sec. 141.404 Treatment technique requirements.
(a) Ground water systems with significant deficiencies. As soon as
possible, but no later than 90 days after receiving written
notification from the State of a significant deficiency, a ground water
system must do one or more of the following: eliminate the source of
contamination, correct the significant deficiency, provide an alternate
source water, or provide a treatment which reliably achieves at least
99.99 percent (4-log) inactivation or removal of viruses before or at
the first customer. Ground water systems which provide 4-log
inactivation or removal of viruses will be required to conduct
compliance monitoring to demonstrate treatment effectiveness. The
ground water system must consult with the State to determine which of
the approaches, or combination of approaches, are appropriate for
meeting the treatment technique requirement. Ground water systems
unable to address the significant deficiencies in 90 days, must develop
a specific plan and schedule for meeting this treatment technique
requirement, submit them to the State, and receive State approval
before the end of the same 90-day period. For the purposes of this
paragraph, a ``significant deficiency'' includes: a defect in design,
operation, or maintenance, or a failure or malfunction of the sources,
treatment, storage, or distribution system that the State determines to
be causing, or has potential for causing the introduction of
contamination into the water delivered to consumers.
(b) Ground water systems with source water contamination. As soon
as possible, but no later than 90 days after the ground water system is
notified that a source water sample is positive for a fecal indicator,
the ground water system must do one or more of the following: eliminate
the source of contamination, correct the significant deficiency,
provide an alternate source water, or provide a treatment which
reliably achieves at least 99.99 percent (4-log) inactivation or
removal of viruses before or at the first customer. Ground water
systems which provide 4-log inactivation or removal of viruses will be
required to conduct compliance monitoring to demonstrate treatment
effectiveness. The ground water system must consult with the State to
determine which of the approaches, or combination of approaches, are
appropriate for meeting the treatment technique requirement. Ground
water systems unable to address the contamination problem in 90 days
must develop a specific plan and schedule for meeting this treatment
technique requirement, submit them to the State, and receive State
approval before the end of the same 90-day period specified previously.
This requirement also applies to ground water systems for which States
have waived source water monitoring under Sec. 141.403(h) and have a
fecal coliform-or E. coli-positive while testing under Sec. 141.21.
(c) Compliance monitoring. Ground water systems that provide 4-log
inactivation or removal of viruses, or begin treatment pursuant to
paragraph (a) or (b) of this section, must monitor the effectiveness
and reliability of treatment as follows:
[[Page 30271]]
(1) Chemical disinfection. (i) Ground water systems serving 3,300
or more people must continuously monitor and maintain the State-
determined residual disinfectant concentration every day the ground
water system serves water to the public.
(ii) Ground water systems serving fewer than 3,300 people must
monitor and maintain the State-determined residual disinfectant
concentration every day the ground water system serves water to the
public. The ground water system will monitor by taking a daily grab
sample during the hour of peak flow or another time specified by the
State. If any daily grab sample measurement falls below the State-
determined residual disinfectant concentration, the ground water system
must take follow-up samples every four hours until the residual
disinfectant concentration is restored to the State-determined level.
(2) UV disinfection. Ground water systems using UV disinfection
must continuously monitor for and maintain the State-prescribed UV
irradiance level every day the ground water system serves water to the
public.
(3) Membrane filtration. Ground water systems that use membrane
filtration as a treatment technology are assumed to be achieving at
least 4-log removal of viruses when the membrane process is operated in
accordance with State-specified compliance criteria developed under
Sec. 142.16(k)(5)(ii) of this chapter, or as provided by EPA, and the
integrity of the membrane is intact. Applicable membrane filtration
technologies are reverse osmosis (RO), nanofiltration (NF), and any
membrane filters developed in the future that have absolute MWCOs
(molecular weight cut-offs) that can achieve 4-log virus removal.
(d) Discontinuing treatment. Ground water systems may discontinue
4-log inactivation or removal of viruses if the State determines based
on an on-site investigation, and documents that determination in
writing, that the need for 4-log inactivation or removal of viruses no
longer exists. Ground water systems are subject to triggered monitoring
in accordance with Sec. 141.403(b).
Sec. 141.405 Treatment technique violations.
The following are treatment technique violations which require the
ground water system to give public notification pursuant to Appendix A
of subpart Q of this part, using the language specified in Appendix B
of subpart Q of this part.
(a) A ground water system with a significant deficiency identified
by a State (as defined in Sec. 141.401) which does not correct the
deficiency, provide an alternative source, or provide 4-log
inactivation or removal of viruses within 90 days, or does not obtain,
within the same 90 days, State approval of a plan and schedule for
meeting the treatment technique requirement in Sec. 141.404, is in
violation of the treatment technique.
(b) A ground water system that detects fecal contamination in the
source water and does not eliminate the source of contamination,
correct the significant deficiency, provide an alternate source water,
or provide a treatment which reliably achieves at least 99.99 percent
(4-log) inactivation or removal of viruses before or at the first
customer within 90 days, or does not obtain within the same 90 days,
State approval of a plan for meeting this treatment technique
requirement, is in violation of the treatment technique unless the
detected sample is invalidated under Sec. 141.403(i) or the treatment
technique is waived under Sec. 141.403(j). Ground water systems which
provide 4-log inactivation or removal of viruses will be required to
conduct compliance monitoring to demonstrate treatment effectiveness.
(c) A ground water system which fails to address either a
significant deficiency as provided in paragraph (a) of this section or
fecal contamination as provided in paragraph (b) of this section
according to the State-approved plan, or by the State-approved
deadline, is in violation of the treatment technique. In addition, a
ground water system which fails to maintain 4-log inactivation or
removal of viruses, is in violation of the treatment technique, if the
failure is not corrected within four hours.
Sec. 141.406 Reporting and record keeping.
(a) Reporting. In addition to the requirements of Sec. 141.31,
ground water systems regulated under this subpart must provide the
following information to the State:
(1) Ground water systems conducting continuous monitoring must
notify the State any time the residual disinfectant concentration
(irradiance in the case of UV) falls below the State-determined value
and is not restored within 4 hours. The ground water system must notify
the State as soon as possible, but in no case later than the end of the
next business day.
(2) Ground water systems taking daily grab samples must notify the
State any time the residual disinfectant concentration falls below the
State-determined value and is not restored within 4 hours, as
determined by follow-up samples. The ground water system must notify
the State as soon as possible, but in no case later than the end of the
next business day.
(3) Ground water systems using membrane filtration must notify the
State any time the membrane is not operated in accordance with standard
operation and maintenance procedures for more than 4 hours, or any
failure of the membrane integrity occurs and is not restored within 4
hours. The ground water system must notify the State as soon as
possible, but in no case later than the end of the next business day.
These operation and maintenance procedures will be provided by EPA or
developed by the State under Sec. 142.16(k)(5)(ii) of this chapter.
(4) If any source water sample is positive for E. coli, coliphage,
or enterococci, the ground water system shall notify the State as soon
as possible, but in no case later than the end of the next business
day, and take corrective action in accordance with Sec. 141.404(b).
(5) If any ground water system has reason to believe that a disease
outbreak is potentially attributable to their drinking water, it must
report the outbreak to the State as soon as possible, but in no case
later than the end of the next business day.
(6) After implementation of any required treatment techniques, a
ground water system must provide as soon as possible, but in no case
later than the end of the next business day, written confirmation to
the State that the corrective action required by Sec. 141.404(a) and
(b) were met.
(7) Notification that the ground water system is currently
providing 4-log inactivation or removal of viruses.
(b) Record keeping. In addition to the requirements of Sec. 141.33,
ground water systems regulated under this subpart must maintain the
following information in their records:
(1) Documentation showing the fecal indicator the State is
requiring the ground water system to use.
(2) Documentation showing consultation with the State on approaches
for addressing significant deficiencies including alternative plans and
schedules and State approval of such plans and schedules.
(3) Documentation showing consultation with the State on approaches
for addressing source water fecal contamination including alternative
plans and schedules and State approval of such plans and schedules.
[[Page 30272]]
PART 142--NATIONAL PRIMARY DRINKING WATER REGULATIONS
IMPLEMENTATION
1. The authority citation for part 142 continues to read as
follows:
Authority: 42 U.S.C. 300f, 300g-1, 300g-2, 300g-3, 300g-4, 300g-
5, 300g-6, 300j-4, 300j-9, and 300j-11.
2. Section 142.14 is amended by adding paragraph (d)(17) to read as
follows:
Sec. 142.14 Records kept by States.
* * * * *
(d) * * *
(17) Records of the currently applicable or most recent State
determinations, including all supporting information and an explanation
of the technical basis for each decision, made under the following
provisions of 40 CFR part 141, subpart S for the Ground Water Rule.
(i) Section 142.16(k)(3)--State determinations of source water
hydrogeologic sensitivity, and determinations of the presence of
hydrogeologic barriers.
(ii) Section 141.404(c) `` notification to individual ground water
systems of the proper residual disinfection concentrations (when using
chemical disinfection), irradiance level (when using UV), or EPA-
specified or State specified compliance criteria (when using membrane
filtration) needed to achieve 4-log inactivation of viruses.
(iii) Section 141.403(g)--waivers of triggered monitoring.
(iv) Section 141.403(h)--reductions of monitoring.
(v) Section 141.403(i)--invalidation of positive source water
samples.
(vi) Section 141.403(j)--waiver of compliance with treatment
technique requirements.
(vii) Section 141.404(a)--notifications of significant
deficiencies, consultation with the ground water systems, including
written confirmation of corrections of significant deficiencies by
ground water systems and written records of State site visits and
approved plans and schedules.
(ix) Section 141.404(d)--determinations of when a ground water
system can discontinue 4-log inactivation or removal of viruses.
* * * * *
3. Section 142.15 is amended by adding paragraphs (c)(6) through
(10) to read as follows:
Sec. 142.15 Reports by States.
* * * * *
(c) * * *
(6) Sanitary surveys. An annual list of ground water systems that
have had a sanitary survey completed during the previous year and an
annual evaluation of the State's program for conducting sanitary
surveys under Sec. 142.16(k)(2).
(7) Hydrogeologic sensitivity assessments. An annual list of ground
water systems that have had a sensitivity assessment completed during
the previous year, a list of those ground water systems which are
sensitive, a list of ground water systems which are sensitive, but for
which the State has determined that a hydrogeologic barrier exists at
the site sufficient for protecting public health, and an annual
evaluation of the State's program for conducting hydrogeologic
sensitivity assessments under Sec. 142.16 (k)(3).
(8) Source water microbial monitoring. An annual list of ground
water systems that have had to test the source water as described under
Sec. 141.403 of this chapter, a list of determinations of invalid
samples, and a list of waivers of source water monitoring provided by
the State.
(9) Treatment technique compliance. An annual list of ground water
systems that have had to meet treatment technique requirements for
significant deficiencies or contaminated source water under
Sec. 141.404 of this chapter, a list of determinations to discontinue
4-log inactivation or removal of viruses, and a list of ground water
systems that violated the treatment technique requirements.
(10) Ground water systems providing 4-log inactivation or removal
of viruses. An annual list of ground water systems that have notified
the State that they are currently providing 4-log inactivation or
removal of viruses.
* * * * *
4. Section 142.16 is amended by adding and reserving paragraphs (i)
and (j) and adding paragraph (k) to read as follows:
Sec. 142.16 Special primacy requirements.
* * * * *
(i) [Reserved]
(j) [Reserved]
(k) Requirements for States to adopt 40 CFR part 141, subpart S. In
addition to the general primacy requirements specified elsewhere in
this part, including the requirement that State regulations are no less
stringent than the Federal requirements, an application for approval of
a State program revision that adopts 40 CFR part 141, subpart S, must
contain a description of how the State will accomplish the following
program requirements:
(1) Enforceable requirements. (i) States must have the appropriate
rules or other authority to ensure that ground water systems take the
steps necessary to address, in accordance with Sec. 141.404(a) of this
chapter, any significant deficiencies identified in the written
notification provided by the State as required under paragraph (k)(2)
of this section.
(ii) States must have appropriate rules or other authority to
ensure that ground water systems respond in writing in regard to the
resolution of significant deficiencies identified in the written
notification provided by the State following identification of the
significant deficiencies.
(iii) States must have the appropriate rules or other authority to
ensure that ground water systems take the steps necessary to address,
in accordance with Sec. 141.404(b) of this chapter, any fecal
contamination identified during routine or triggered monitoring in
accordance with Sec. 141.403(a) and (b) of this chapter.
(2) Sanitary survey. In its primacy application the State must
describe how it, or an authorized agent, will implement a sanitary
survey program that meets the requirements of this section.
(i) For the purposes of this paragraph (k)(2), ``sanitary survey''
includes, but is not limited to, an onsite review of the water source
(identifying sources of contamination by using results of source water
assessments or other relevant information where available), facilities,
equipment, operation, maintenance, and monitoring compliance of a
public water system to evaluate the adequacy of the system, its sources
and operations and the distribution of safe drinking water.
(ii) The State, or an authorized agent, must conduct sanitary
surveys for all ground water systems. The sanitary survey must address
the eight sanitary survey components listed in paragraphs (k)(2)(ii)(A)
through (H) of this section no less frequently than every three years
for community systems and no less frequently than every five years for
noncommunity systems. The first sanitary survey for community water
systems must be completed by [DATE 6 YEARS AFTER DATE OF PUBLICATION OF
THE FINAL RULE IN THE FEDERAL REGISTER] and for noncommunity water
systems, must be completed by [DATE 8 YEARS AFTER DATE OF PUBLICATION
OF THE FINAL RULE IN THE FEDERAL REGISTER].
(A) Source.
(B) Treatment.
(C) Distribution system.
(D) Finished water storage.
(E) Pumps, pump facilities, and controls.
[[Page 30273]]
(F) Monitoring and reporting and data verification.
(G) System management and operation.
(H) Operator compliance with State requirements.
(iii) After the initial sanitary survey for ground water systems in
accordance with Sec. 142.16(k)(2)(ii), the State may reduce the
frequency of sanitary surveys for community water systems to no less
frequently than every five years, if the ground water system either
treats to 4-log inactivation or removal of viruses or has an
outstanding performance record documented in previous inspections and
has no history of total coliform MCL or monitoring violations under
Sec. 141.21 of this chapter as determined by the State, since the last
sanitary survey under the current ownership. In its primacy
application, the State must describe how it will decide whether a
community water system has outstanding performance and is thus eligible
for sanitary surveys at a reduced frequency.
(iv) States may complete components of a sanitary survey as part of
a staged or phased State review process within the established
frequency specified in paragraph (k)(2)(ii) or (iii) of this section.
In its primacy application, a State which plan to complete the sanitary
survey in a staged or phased State review process must indicate which
approach it will take and provide the rationale for the specified time
frames for sanitary surveys conducted on a staged or phased approach
basis.
(v) Sanitary surveys that meet the requirements of this subpart,
including the requisite eight components identified in paragraph
(k)(2)(ii) of this section and conducted at the specified frequency,
are considered to meet the requirements for sanitary surveys under the
Total Coliform Rule (TCR) as described in Sec. 141.21 of this chapter.
Note however, compliance only with the TCR sanitary survey requirements
may not be adequate to meet the revised scope and frequency sanitary
survey requirement of this subpart.
(vi) States must provide ground water systems with written
notification identifying and describing any significant deficiencies
identified at the ground water system no later than 30 days after
identifying the significant deficiencies. States will provide ground
water systems with written notification by certified mail or on-site
from the sanitary survey inspector. In its primacy application, the
State must indicate how it will define what constitutes a significant
deficiency for purposes of this subpart. For the purposes of this
paragraph, a ``significant deficiency'' includes: a defect in design,
operation, or maintenance, or a failure or malfunction of the sources,
treatment, storage, or distribution system that the State determines to
be causing, or has potential for causing the introduction of
contamination into the water delivered to consumers.
(vii) In its primacy application, the State must describe how it
will consult with the ground water system regarding the treatment
technique requirements specified in Sec. 141.404 and criteria for
determining when a ground water system has met the 4-log inactivation
or removal of viruses of this chapter.
(viii) States must confirm that the deficiency has been addressed,
either through written confirmation from ground water systems or a site
visit by the State, within 30 days after the ground water system has
met the treatment technique requirements under Sec. 141.404(a) of this
chapter.
(ix) In its primacy application, the State must specify if and how
it will integrate Source Water Assessment and Protection Program
(SWAPP) susceptibility determinations into the sanitary survey and the
definition of significant deficiency.
(3) Hydrogeologic sensitivity assessments. (i) For the purposes of
this paragraph (k)(3), ``hydrogeologic sensitivity assessment'' means
the methodology used by the State to identify whether ground water
systems are obtaining water from karst, gravel, or fractured bedrock
aquifers. A State may add additional hydrogeologic sensitive settings,
e.g., volcanic aquifers. A well obtaining water from a karst, gravel or
fractured bedrock aquifer is sensitive to fecal contamination unless
the well is protected by a hydrogeologic barrier. A ``hydrogeologic
barrier'' consists of physical, chemical and biological factors that,
singularly or in combination, prevent the movement of viable pathogens
from a contaminant source to a ground water system well.
(ii) The State, or an authorized agent, must conduct a one-time
hydrogeologic sensitivity assessment for all existing ground water
systems not providing 4-log inactivation or removal of viruses by [DATE
SIX YEARS AFTER DATE OF PUBLICATION OF THE FINAL RULE IN THE FEDERAL
REGISTER] for community water systems and by [DATE EIGHT YEARS AFTER
DATE OF PUBLICATION OF THE FINAL RULE IN THE FEDERAL REGISTER] for non-
community water systems. The State, or an authorized agent, must
conduct a hydrogeologic sensitivity assessment for new systems prior to
their serving water to the public.
(iii) In its primacy application, a State must identify its
approach to determine the adequacy of a hydrogeologic barrier, if
present, as part of its effort to determine the sensitivity of a ground
water system in a hydrogeologic sensitivity assessment.
(4) Source water microbial monitoring. (i) In its primacy
application, the State must identify its approach and rationale for
determining which of the fecal indicators (E. coli, coliphage, or
enterococci) ground water systems must use in accordance with
Sec. 141.403(d) of this chapter.
(ii) The State may waive triggered source water monitoring as
described in Sec. 141.403(b) of this chapter due to a total coliform-
positive sample, on a case-by-case basis, if the State determines that
the total coliform positive sample is associated solely with a
demonstrated distribution system problem. In such a case, a State
official must document the decision, including the rationale for the
decision, in writing, and sign the document.
(iii) The State may reduce routine source water monitoring to
quarterly if a hydrogeologically sensitive ground water system detects
no fecal indicator-positive samples in the most recent twelve
consecutive monthly samples during the months the ground water system
is in operation. Moreover, the State may, after those twelve
consecutive monthly samples, waive source water monitoring altogether
for a ground water system if the State determines, in writing, that
fecal contamination of the well(s) has not been identified and is
highly unlikely, based on the sampling history, land use pattern,
disposal practices in the recharge area, and proximity of septic tanks
and other fecal contamination sources. If the State determines that
circumstances have changed, the State has the discretion to reinstate
routine monthly monitoring. In any case, a State official must document
the determination in writing, including the rationale for the
determination, and sign the document.
(iv) The State may determine a source water sample to be invalid
only if the laboratory establishes that improper sample analysis
occurred or the State has substantial grounds to believe that a sample
result is due to circumstances that do not reflect source water
quality. In such a case, a State official must document the decision,
including the rationale for the decision, in writing, and sign the
document. The written documentation must state the specific cause of
the invalid sample and what action the ground water system or
laboratory has taken or must take to
[[Page 30274]]
correct this problem. A positive sample may not be invalidated by the
State solely on the grounds that repeat samples are negative, though
this could be considered along with other evidence that the original
sample result does not reflect source water quality.
(v) A ground water system may apply to the State, and the State may
consider, on a one-time basis, to waive compliance with the treatment
technique requirements in Sec. 141.404(a) of this chapter, after a
single fecal indicator-positive from a routine source water sample as
required in Sec. 141.403(a) of this chapter, if all the following
conditions are met:
(A) The ground water system collects five repeat source water
samples within 24 hours after being notified of a source water fecal
positive result;
(B) The ground water system has the samples analyzed for the same
fecal indicator as the original sample;
(C) All the repeat samples are fecal indicator negative; and
(D) All previous source water samples (routine and triggered)
during the past 5 years were fecal indicator-negative.
(5) Treatment technique requirements. (i) In its primacy
application, the State must describe how it must provide every ground
water system treating to 4-log inactivation or removal the disinfectant
concentration (or irradiance) and contact time to achieve 4-log virus
inactivation or removal. EPA recommends that the State use applicable
EPA-developed CT tables (IT (the product of irradiance, in mW/
cm2, multiplied by exposure time, in seconds) in the case of
UV disinfection) to determine the concentration (or irradiance) and
contact time that it will require ground water systems to achieve 4-log
virus inactivation.
(ii) If the State intends to approve membrane filtration for
treatment it must, in its primacy application, describe the monitoring
and compliance requirements, including membrane integrity testing, that
it will require of ground water systems to demonstrate proper operation
of membrane filtration technologies.
(iii) In its primacy application, a State must describe the
approach it must use to determine which specific treatment technique
option (correcting the deficiency, eliminating the source of
contamination, providing an alternative source, or providing 4-log
inactivation or removal of viruses) is appropriate for addressing
significant deficiencies or fecally contaminated source water and under
what circumstances. In addition, the State must describe the approach
it intends to use when consulting with ground water systems on
determining the treatment technique options.
(iv) States must confirm that the ground water system has addressed
the source water fecal contamination identified under routine or
triggered monitoring in accordance with Sec. 141.403(a) and (b) of this
chapter, either through written confirmation from ground water systems
or a site visit by the State, within 30 days after the ground water
system has met the treatment technique requirements under
Sec. 141.404(b) of this chapter.
[FR Doc. 00-10763 Filed 5-9-00; 8:45 am]
BILLING CODE 6560-50-P