NR 809.565(3)(b)2.2. ‘Reduced monitoring.’ Water suppliers for public water systems may reduce monitoring for bromate from monthly to once per quarter, if the water supplier demonstrates that the public water system’s running annual average concentration for bromate is =0.0025 mg/L based on monthly bromate measurements under par. (b) for the most recent four quarters. Samples shall be analyzed using Method 317.0 Revision 2.0, 326.0 or 321.8. If the running annual average bromate concentration is >0.0025 mg/L, the system must resume routine monitoring required by par. (b).

NR 809.565(4)(a)(a) Chlorine and chloramines. Water suppliers for public water systems shall perform routine monitoring by measuring the residual disinfectant level at the same points in the distribution system and at the same time as total coliforms are sampled, as specified in s. NR 809.31. The department may allow suppliers for surface water systems to take disinfectant residual samples at points other than the total coliform sampling points if the department determines that such points are more representative of disinfected water quality within the distribution system. Water suppliers for surface water systems may use the results of residual disinfectant concentration sampling conducted under s. NR 810.38 (1) (h) for unfiltered systems or s. NR 810.38 (2) (d) for public water systems that filter, in lieu of taking separate samples. Monitoring may not be reduced.

NR 809.565(4)(b)1.1. ‘Routine monitoring.’ Water suppliers for community, nontransient noncommunity, and transient noncommunity water systems that use chlorine dioxide for disinfection or oxidation shall take daily samples at the entrance to the distribution system. For any daily sample that exceeds the MRDL, the water supplier shall take samples in the distribution system the following day at the locations required by subd. 2., in addition to the sample required at the entrance to the distribution system.

NR 809.565(4)(b)2.2. ‘Additional monitoring.’ On each day following a routine sample monitoring result that exceeds the MRDL, the water supplier shall take 3 chlorine dioxide distribution system samples. If chlorine dioxide or chloramines are used to maintain a disinfectant residual in the distribution system, or if chlorine is used to maintain a disinfectant residual in the distribution system and there are no disinfection addition points after the entrance to the distribution system, i.e., no booster chlorination, the water supplier shall take 3 samples as close to the first customer as possible, at intervals of at least 6 hours. If chlorine is used to maintain a disinfectant residual in the distribution system and there are one or more disinfection addition points after the entrance to the distribution system, i.e., booster chlorination, the water supplier shall take one sample at each of the following locations: as close to the first customer as possible, in a location representative of average residence time, and as close to the end of the distribution system as possible, reflecting maximum residence time in the distribution system.

NR 809.565(4)(b)3.3. ‘Reduced monitoring.’ Chlorine dioxide monitoring may not be reduced.

NR 809.565(5)(5) Monitoring frequency and location for disinfectant byproduct precursors. Water suppliers for public water systems shall monitor at the following frequency and locations for disinfection byproduct precursors (DBPP):

NR 809.565(5)(a)1.1. Water suppliers for public water systems which use conventional filtration treatment and are supplied by a surface water source or by a groundwater source under the direct influence of surface water shall monitor each treatment plant monthly for TOC no later than the point of combined filter effluent turbidity monitoring and representative of the treated water.

NR 809.565(5)(a)2.2. All water suppliers for public water systems required to monitor under subd. 1. shall also monitor for TOC in the source water prior to any treatment at the same time as monitoring for TOC in the treated water.

NR 809.565(5)(a)3.3. At the same time as the source water sample is taken, all water suppliers shall monitor for alkalinity in the source water prior to any treatment. Water suppliers shall take one paired sample and one source water alkalinity sample per month per plant at a time representative of normal operating conditions and influent water quality.

NR 809.565(5)(b)(b) Reduced monitoring. Water suppliers for public water systems which use conventional filtration treatment and are supplied by a surface water source or by a groundwater source under the direct influence of surface water and which have an average treated water TOC of less than 2.0 mg/L for 2 consecutive years, or less than 1.0 mg/L for one year, may reduce monitoring for both TOC and alkalinity to one paired sample and one source water alkalinity sample per plant per quarter. The water supplier shall revert to routine monitoring in the month following the quarter when the annual average treated water TOC >2.0 mg/L for the public water system.

NR 809.565(6)(6) Monitoring plans. Each water supplier for a public water system required to monitor under this subchapter shall develop and implement a monitoring plan, and shall maintain the plan and make it available for inspection by the department and the general public no later than 30 days following the applicable compliance dates in s. NR 809.562 (2).

NR 809.565(6)(a)(a) Water suppliers for public water systems which are supplied by a surface water source or by a groundwater source under the direct influence of surface water and which serve more than 3,300 people shall submit a copy of the monitoring plan to the department no later than the date of the first report required under s. NR 809.567. The department may also require water suppliers for any other public water system to submit a monitoring plan. After review, the department may require changes in any plan elements.

NR 809.565(6)(b)1.1. Specific locations and schedules for collecting samples for any parameters included in this subchapter.

NR 809.565(6)(b)2.2. How the water supplier will calculate compliance with MCLs, MRDLs and treatment techniques.

NR 809.565(6)(b)3.3. If approved for monitoring as a consecutive system, or if providing water to a consecutive system, under s. NR 809.77, the sampling plan shall reflect the entire distribution system.

NR 809.566(1)(a)(a) If compliance is based on a running annual average of monthly or quarterly samples or an annual average and the water supplier for a public water system fails to monitor for TTHM, HAA5 or bromate, this failure to monitor shall be treated as a monitoring violation for the entire period covered by the annual average.

NR 809.566(1)(b)(b) If compliance is based on a running annual average of monthly or quarterly samples or averages and the water supplier’s failure to monitor the public water system makes it impossible to determine compliance with MRDLs for chlorine and chloramines, failure to monitor shall be treated as a monitoring violation for the entire period covered by the annual average.

NR 809.566(1)(d)(d) If, during the first year of monitoring under s. NR 809.565, any individual quarter’s average will cause the running annual average of that public water system to exceed the MCL, the public water system is out of compliance at the end of that quarter.