NR 809.33(2)(b)(b) The requirements of this section for filtered public water systems apply to all public water systems required by s. NR 810.29 to provide filtration treatment, whether or not the public water system is currently operating a filtration system.

NR 809.33(2)(c)(c) The requirements of this section for unfiltered public water systems apply only to unfiltered public water systems that met and continue to meet the filtration avoidance criteria in s. NR 810.30 as applicable.

NR 809.33(3)(3) Requirements. Public water systems subject to this section shall comply with the following requirements:

NR 809.33(3)(a)1.1. Water suppliers shall have conducted and submitted to EPA an initial round of source water monitoring for treatment plants existing as of January 5, 2006 under 40 CFR part 141 National Primary Drinking Water Regulations Subpart W that determined the level of treatment for Cryptosporidium needed under s. NR 810.34.

NR 809.33(3)(a)2.2. Water suppliers shall conduct source water monitoring as part of the treatment approval process for plants constructed after January 5, 2006 under s. NR 811.21 (1) (f). This monitoring shall include Cryptosporidium, E. coli, and turbidity to determine what level of Cryptosporidium treatment shall be provided using the requirements of the bin classifications under s. NR 810.34.

NR 809.33(3)(a)3.3. A second round of source water monitoring for each plant that treats a surface water or GWUDI source shall be conducted by the water supplier and submitted to the department as required in s. NR 809.331 (2). This monitoring may include sampling for Cryptosporidium, E. coli, and turbidity as described in ss. NR 809.331 to 809.336, to determine what level, if any, of additional Cryptosporidium treatment the public water system shall provide.

NR 809.33(3)(b)(b) Water suppliers that plan to make a significant change to the disinfection practice at a public water system shall develop disinfection profiles and calculate disinfection benchmarks, as described in s. NR 810.32.

NR 809.33(3)(c)(c) Water suppliers for filtered public water systems shall determine their Cryptosporidium treatment bin classification as described in s. NR 810.34 and provide additional treatment for Cryptosporidium, if required, as described in s. NR 810.35. All unfiltered public water systems shall provide treatment for Cryptosporidium as described in s. NR 810.36. Filtered and unfiltered public water systems shall implement Cryptosporidium treatment according to the schedule in s. NR 810.37.

NR 809.33(3)(d)(d) Water suppliers for public water systems with an uncovered finished water storage facilities shall comply with the requirements to cover the facility or treat the discharge from the facility as described in s. NR 810.28.

NR 809.33(3)(e)(e) Water suppliers for public water systems required to provide additional treatment for Cryptosporidium shall implement microbial toolbox options that are designed and operated as described in ss. NR 810.41 to 810.46.

NR 809.33(3)(f)(f) Water supplier shall comply with the applicable recordkeeping and reporting requirements described in ss. NR 809.336 and 809.82.

NR 809.33(4)(4) Surface water treatment technique violations. Surface water and GWUDI public water systems are in violation of the treatment technique requirements for turbidity if any of the requirements of s. NR 810.29 (1) to (4) are not met.

NR 809.331(1)(1) Initial round of source water monitoring. Water suppliers shall have conducted the following monitoring according to the schedule in sub. (3) Table H, at treatment plants existing as of January 5, 2006 unless the public water system meets the monitoring exemption criteria in sub. (4). The initial source water monitoring requirements were conducted under 40 CFR part 141 National Primary Drinking Water Regulations Subpart W with EPA wholly responsible for implementation. For public water systems with treatment plants constructed after January 5, 2006 the department may require the following initial monitoring as part of the approval process under s. NR 811.21 (1) (f).

NR 809.331(1)(a)(a) Water suppliers for filtered public water systems serving at least 10,000 people shall sample their source water for Cryptosporidium, E. coli, and turbidity at least monthly for 24 months.

NR 809.331(1)(b)(b) Water suppliers for unfiltered public water systems serving at least 10,000 people shall sample their source water for Cryptosporidium at least monthly for 24 months.

NR 809.331(1)(c)(c) Water suppliers for filtered public water systems serving fewer than 10,000 people shall sample their source water for E. coli at least once every two weeks for 12 months. A filtered public water system serving fewer than 10,000 people may avoid E. coli monitoring if the water supplier notifies the department that Cryptosporidium will be monitored for as described in sub. (3). The water supplier shall notify the department no later than 3 months prior to the date the public water system is required to start E. coli monitoring under sub. (3).

NR 809.331(1)(d)(d) Water suppliers for filtered public water systems serving fewer than 10,000 people shall sample their source water for Cryptosporidium at least twice per month for 12 months or at least monthly for 24 months if based on monitoring conducted under par. (c), and if they meet one of the following:

NR 809.331(1)(d)1.1. For public water systems using lake or reservoir sources, the annual mean E. coli concentration is greater than 10 E. coli /100 mL.

NR 809.331(1)(d)2.2. For public water systems using flowing stream sources, the annual mean E. coli concentration is greater than 50 E. coli /100 mL.

NR 809.331(1)(d)4.4. Public water systems using groundwater under the direct influence of surface water (GWUDI) shall comply with the requirements of this paragraph based on the E. coli level that applies to the nearest surface water body. If no surface water body is nearby, the public water system shall comply based on the requirements that apply to public water systems using lake or reservoir sources.

NR 809.331(1)(e)(e) For filtered public water systems serving fewer than 10,000 people, the department may approve monitoring for an indicator other than E. coli under par. (c). The department also may approve an alternative to the E. coli concentration in par. (d) 1. to 3. to trigger Cryptosporidium monitoring. This approval by the department shall be provided to the public water system in writing and shall include the basis for the department’s determination that the alternative indicator or trigger level will provide a more accurate identification of whether a public water system will exceed the Bin 1 Cryptosporidium level in s. NR 810.34.

NR 809.331(1)(f)(f) Water suppliers for unfiltered public water systems serving fewer than 10,000 people shall sample their source water for Cryptosporidium at least twice per month for 12 months or at least monthly for 24 months.

NR 809.331(1)(g)(g) Water suppliers may sample more frequently than required under this section if the sampling frequency is evenly spaced throughout the monitoring period.

NR 809.331(2)(2) Second round of source water monitoring. Water supplier shall conduct a second round of source water monitoring that meets the requirements for monitoring parameters, frequency, and duration described in sub. (1), unless they meet the monitoring exemption criteria in sub. (4). Water suppliers shall conduct this monitoring on the schedule in sub. (3).

NR 809.331(3)(3) Monitoring schedule. According to EPA requirements, water supplier shall begin the monitoring required in subs. (1) and (2) no later than the month beginning with the date listed in Table H: