R 325.10602 Maximum contaminant levels (MCLs) for microbiological contaminants.

Rule 602. (1) Beginning April 1, 2016, a community or noncommunity water supply is in compliance with the MCL for E. coli for samples taken under R 325.10704a to R 325.10704k unless 1 or more of the following conditions occur: (a) The supply has an E. coli-positive repeat sample following a total coliform-positive routine sample. (b) The supply has a total coliform-positive repeat sample following an E. coli-positive routine sample. (c) The supply fails to take all required repeat samples following an E. coli-positive routine sample. (d) The supply fails to test for E. coli when a repeat sample tests positive for total coliform. Note to this subrule: For purposes of the public notification requirements in R 325.10401a to R 325.10409, violation of the MCL may pose an acute risk to health. (2) Beginning April 1, 2016, a supply shall determine compliance with the MCL for E. coli in subrule (1) of this rule for each month in which it is required to monitor for total coliforms. (3) The best technology, treatment techniques, or other means available for achieving compliance with the maximum contaminant level for total coliforms in subrule (5) of this rule until March 31, 2016 and for achieving compliance with the maximum contaminant level for E. coli in subrule (1) of this rule beginning April 1, 2016 are all of the following: (a) Protection of wells from fecal contamination by appropriate placement and construction. (b) Maintenance of a disinfectant residual throughout the distribution system. (c) Proper maintenance of the distribution system including appropriate pipe replacement and repair procedures, main flushing programs, proper operation and maintenance of storage tanks and reservoirs, cross connection control, and continual maintenance of positive water pressure in all parts of the distribution system. (d) Filtration and disinfection of surface water, as described in the surface water treatment provisions of R 325.10611 to R 325.10611n, R 325.10720 to R 325.720e, and R 325.10722, or disinfection of groundwater, as described in the groundwater provisions of R 325.10612 to R 325.10612b and R 325.10739 to R 325.10739b, using strong oxidants such as chlorine, chlorine dioxide, or ozone. (e) For supplies using ground water, compliance with the requirements of an EPA- approved state Wellhead Protection Program developed and implemented under section 1428 of the federal act. (4) The technology, treatment techniques, or other means available identified in subrule (3) of this rule are considered affordable technology, treatment techniques, or other means available to supplies serving 10,000 or fewer people for achieving compliance with the maximum contaminant level for total coliforms in subrule (5) of this rule until March 31, 2016 and for achieving compliance with the maximum contaminant level for E. coli in subrule (1) of this rule beginning April 1, 2016. (5) Until March 31, 2016 all of the following apply: (a) The total coliform MCL is based on the presence or absence of total coliforms in a sample, rather than coliform density. Either of the following applies to the total coliform MCL: (i) For a supply that collects at least 40 samples per month, if no more than 5.0 percent of the samples collected during a month are total coliform-positive, the supply is in compliance with the MCL for total coliforms. (ii) For a supply that collects fewer than 40 samples per month, if no more than one sample collected during a month is total coliform-positive, the supply is in compliance with the MCL for total coliforms. (b) A fecal coliform-positive repeat sample or E. coli-positive repeat sample, or a total coliform-positive repeat sample following a fecal coliform-positive or E. coli-positive routine sample, constitutes a violation of the MCL for total coliforms. For purposes of the public notification requirements in R 325.10401a to R 325.10409, this is a violation that may pose an acute risk to health. (c) A supply shall determine compliance with the MCL for total coliforms in this subrule for each month in which it is required to monitor for total coliforms.