Section 809.562. General requirements for disinfection byproducts and disinfection residuals Stage 1 DBP.

 

(1)   General. The following requirements establish criteria under which water supplier for community water systems, or CWSs, and nontransient, noncommunity water systems, or NTNCWSs, which add a chemical disinfectant to the water in any part of the drinking water treatment process shall modify their practices to meet MCLs and MRDLs in s. NR 809.561 (2) and (3) (a) , respectively, and shall meet the treatment technique requirements for disinfection byproduct precursors in s. NR 809.561 (4) . Water suppliers for transient noncommunity water systems, or TNCWSs, that use chlorine dioxide as a disinfectant or oxidant shall modify their practices to meet the MRDL for chlorine dioxide in s. NR 809.561 (3) (a) according to the criteria established in this section. MCLs have been established for TTHM and HAA5 and treatment technique requirements for disinfection byproduct precursors to limit the levels of known and unknown disinfection byproducts which may have adverse health effects. These disinfection byproducts may include chloroform, bromodichloromethane, dibromochloromethane, bromoform, dichloroacetic acid, and trichloroacetic acid.

(2)   Compliance timeframes . Unless otherwise noted, all public water systems shall comply with the requirements of this subchapter as follows:

(a) All public water systems serving 10,000 or more persons that are CWSs or NTNCWSs and that are supplied by a surface water source or by a groundwater source under the direct influence of surface water shall comply with this subchapter beginning January 1, 2002.

(b) Public water systems serving fewer than 10,000 persons that are CWSs or NTNCWSs and that are supplied by a surface water source or by a groundwater source under the direct influence of surface water and all public water systems using only groundwater not under the direct influence of surface water shall comply with this subchapter beginning January 1, 2004.

(c) Public water systems serving 10,000 or more persons that are transient NCWSs and use chlorine dioxide as a disinfectant or oxidant and are supplied by a surface water source or by a groundwater source under the direct influence of surface water shall comply with any requirements for chlorine dioxide and chlorite in this subchapter beginning January 1, 2002.

(d) Public water systems that are transient NCWSs and use chlorine dioxide as a disinfectant or oxidant and that serve fewer than 10,000 persons and are supplied by a surface water source or by a groundwater source under the direct influence of surface water or that are public water systems using only groundwater not under the direct influence of surface water shall comply with any requirements for chlorine dioxide in this subchapter beginning January 1, 2004.

(e) A consecutive system that does not add a disinfectant but delivers water that has been treated with a primary or residual disinfectant other than ultraviolet light, shall comply with analytical and monitoring requirements for chlorine and chloramines in s. NR 809.565 (6) (a) and the compliance requirements in s. NR 809.566 (3) (a) beginning April 1, 2009 and shall report monitoring results under s. NR 809.567 (3) .

(3)   Operator certification. Each CWS and NTNCWS regulated under s. NR 809.561 shall be operated by qualified personnel who meet the requirements specified in ch. NR 114 , subchs. I and III and are included in a department register of qualified operators.

(4)   Response to microbiological contamination. Notwithstanding the MRDLs in s. NR 809.561 (3) (a) , water suppliers for public water systems may increase in the distribution system residual disinfectant levels of chlorine or chloramines, but not chlorine dioxide, to a level and for a time necessary to protect public health, to address specific microbiological contamination problems caused by circumstances such as, but not limited to, distribution line breaks, storm run-off events, source water contamination events or cross-connection events.

(5)   Public notification of MCL or MRDL violations. The water supplier of a public water system shall provide public notification in compliance with subch. VII when the MCL or MRDL or disinfectant residual is exceeded.

(6)   Required additional health information. Water suppliers for CWSs that detect TTHM above 0.080 mg/l, but are not in violation of the MCL in s. NR 809.561 (2) , based on an annual average, monitored and calculated under the provisions of s. NR 809.565 , shall provide copies of health effects language prescribed in subch. VII and s. NR 809.835 to the users of the CWS in the CCR.

CR 09-073 : cr. Register November 2010 No. 659 , eff. 12-1-10; CR 15-049 : am. (3) Register March 2016 No. 723 , eff. 4-1-16; correction in (3) made under s. 35.17 , Stats., Register March 2016 No. 723 , eff. 4-1-16.