(a) The requirements of this subpart H constitute national primary drinking water regulations. These regulations establish criteria under which filtration is required as a treatment technique for public water systems supplied by a surface water source and public water systems supplied by a ground water source under the direct influence of surface water. In addition, these regulations establish treatment technique requirements in lieu of maximum contaminant levels for the following contaminants:
(1) At least 99.9 percent (3-log) removal and/or inactivation of
(2) At least 99.99 percent (4-log) removal and/or inactivation of viruses between a point where the raw water is not subject to recontamination by surface water runoff and a point downstream before or at the first customer.
(b) A public water system using a surface water source or a ground water source under the direct influence of surface water is considered to be in compliance with the requirements of paragraph (a) of this section if:
(1) It meets the requirements for avoiding filtration in § 141.71 and the disinfection requirements in § 141.72(a); or
(2) It meets the filtration requirements in § 141.73 and the disinfection requirements in § 141.72(b).
(c) Each public water system using a surface water source or a ground water source under the direct influence of
(d)
(e)