NR 809.60(7)(a)(a) Water suppliers for public water systems required to be monitored quarterly shall calculate LRAAs for TTHM and HAA5 to determine that each monitoring location LRAA does not exceed the MCL.

NR 809.60(7)(a)1.1. If four consecutive quarters of monitoring are not completed, compliance with the MCL shall be based on the average of the available data from the most recent four quarters.

NR 809.60(7)(a)2.2. If more than one sample per quarter is collected at a monitoring location, all samples taken in the quarter at that location shall be averaged to determine a quarterly average to be used in the LRAA calculation.

NR 809.60(7)(b)(b) Water suppliers for public water systems required to be monitored yearly or less frequently shall establish compliance for TTHM and HAA5 by using each sample collected to determine if it is less than the MCL.

NR 809.60(7)(c)(c) A public water system is in violation of the monitoring requirements for each quarter that a LRAA is calculated using a quarter in which the water supplier failed to monitor.

NR 809.61(1)(a)(a) A water supplier that submitted an IDSE report to EPA under Subpart U of 40 CFR part 141 shall begin monitoring at the locations and months recommended in the IDSE report submitted to EPA under Subpart U of 40 CFR part 141.605 following the schedule in s. NR 809.60 (3), unless the department requires other locations or additional locations after its review.

NR 809.61(1)(b)(b) A water supplier that submitted a 40/30 certification from EPA under Subpart U of 40 CFR part 141.603 or the department under s. NR 809.974 or for a public water system that qualified for a very small system waiver from EPA under Subpart U of 40 CFR 141.604 or the department under s. NR 809.975 or for a public water system that is a nontransient noncommunity water system serving <10,000, shall monitor at the location or locations and dates identified in the public water system’s monitoring plan in s. NR 809.565 (6), updated as required by s. NR 809.62.

NR 809.61(1)(c)(c) Monitoring shall be conducted at no fewer than the number of locations identified in Table Y.

NR 809.61(1)(d)(d) All public water systems shall be monitored during the month of highest DBP concentrations.

NR 809.61(1)(e)(e) Water suppliers for public water systems on quarterly monitoring shall take dual sample sets every 90 days at each monitoring location, except for water supplier for surface water systems or groundwater under the direct influence of surface water systems serving 500–3,300. Water suppliers for groundwater systems serving 500–9,999 on annual monitoring shall take dual sample sets at each monitoring location. All other public water systems on annual monitoring and surface water systems or groundwater under the direct influence of surface water systems serving 500–3,300 shall take individual TTHM and HAA5 samples, instead of a dual sample set, at the locations with the highest TTHM and HAA5 concentrations, respectively. For public water systems serving fewer than 500 people, only one location with a dual sample set per monitoring period is required if the highest TTHM and HAA5 concentrations occur at the same location and month.

NR 809.61(1)(f)(f) Water suppliers for undisinfected systems that begin using a disinfectant other than UV light after the dates for complying with the Initial Distribution System Evaluation requirements shall consult with the department to identify compliance monitoring locations for s. NR 809.60 and develop a monitoring plan under s. NR 809.62 that includes those monitoring locations.

NR 809.61(2)(a)(a) Samples shall be analyzed using an approved method listed in s. NR 809.563 (3) Table S for TTHM and HAA5.

NR 809.61(2)(b)(b) The analysis under par. (a) shall be conducted by laboratories that are certified by EPA or the department under ch. NR 149.

NR 809.62(1)(1) General monitoring plan requirements. Monitoring plans shall be developed, implemented and kept up to date by water suppliers for all public water systems that are required to be monitored for TTHMs and HAA5s and shall be kept on file for department and public review.

NR 809.62(1)(a)(a) Monitoring plans under this section shall be completed no later than the date the public water system is required to begin initial compliance monitoring under s. NR 809.60 (3).