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

Current through June 24, 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					 809.975 were repealed by CR 15-049.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.
(c) Monitoring shall be conducted at no fewer
				  than the number of locations identified in Table Y.
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.