Wisconsin Administrative Code
Department of Natural Resources
NR 800 - Environmental Protection - Water Supply
Chapter NR 809 - Safe Drinking Water
Subchapter III - Maximum Contaminant Levels, Maximum Residual Disinfectant Levels, Monitoring, Analytical Requirements and Control of Disinfection Byproducts, Disinfection Residuals and Stage 1 and Stage 2 DBP
Section NR 809.61 - Routine monitoring for Stage 2 DBP

Universal Citation: WI Admin Code § NR 809.61

Current through August 26, 2024

(1) MONITORING.

(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.

(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.

Note: Sections NR 809.974 and 809.975 were repealed by CR 15-049. Corrections will be made in future rulemaking.

Table Y

Stage 2 DBP - Disinfection byproducts monitoring frequency, locations, and sample type

Source water type	Population size category	Monitoring frequency	Distribution system monitoring location total per monitoring period	Sample type
Surface water and GWUDI:
	<500	Annual	2	Individual; option of one dual sample at one location if highest DBP concentrations are at the same location and month
	500-3,300	quarterly	2	Individual
	3,301-9,999	quarterly	2	Dual
	10,000-49,999	quarterly	4	Dual
	50,000-249,999	quarterly	8	Dual
	250,000-999,999	quarterly	12	Dual
	1,000,000-4,999,999	quarterly	16	Dual
	>= 5,000,000	quarterly	20	Dual
Groundwater:
	<500	Annual	2	Individual; option of one dual sample at one location if highest DBP concentrations are at the same location and month
	500-9,999	Annual	2	Dual
	10,000-99,999	quarterly	4	Dual
	100,000-499,999	quarterly	6	Dual
	>= 500,000	quarterly	8	Dual

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

(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 5003,300. Water suppliers for groundwater systems serving 5009,999 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 5003,300 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.

(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.

(2) ANALYTICAL METHODS AND LABORATORIES.

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

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

Disclaimer: These regulations may not be the most recent version. Wisconsin may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.

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