Methyl-t-butyl ether (MTBE)
Analysis under this section shall be conducted by a laboratory certified under ch. NR 149
using EPA methods 502.2, 524.2, 524.3, 551.1 for contaminants listed in par. (e)
and EPA methods listed in s. NR 809.203
, Table CM for contaminants listed in par. (f)
(2) Sulfate monitoring.
Monitoring for sulfate shall be conducted as required by the department.
(3) Reporting requirements.
Reporting requirements under this section shall be as required under s. NR 809.80
(4) Treatment techniques for acrylamide and epichlorohydrin.
In lieu of MCLs and monitoring for acrylamide and epichlorohydrin, the following treatment techniques and reporting are required. Each water supplier for public water system shall certify annually in writing to the department using third party or manufacturer's certification, that when acrylamide and epichlorohydrin are used in the treatment of drinking water, the combination, or product, of dose and monomer level does not exceed the levels specified as follows:
A water supplier may rely on certification from manufacturers or third parties, as approved by the department.
NR 809.25 History
History: CR 09-073
: cr. Register November 2010 No. 659
, eff. 12-1-10; CR 15-049
: am. (1) (g) Register March 2016 No. 723
, eff. 4-1-16.
Distribution system microbiological contaminant maximum contaminant levels.
The following are the maximum contaminant levels for coliform bacteria applicable to public water systems.
The MCL for E. coli
is exceeded if any of the following occurs:
The public water system has an E. coli
-positive repeat sample following a total coliform-positive routine sample.
The public water system has a total coliform-positive repeat sample following an E. coli
-positive routine sample.
The public water system fails to take all required repeat samples following an E. coli
-positive routine sample.
The public water system fails to test for E. coli
when any repeat sample tests positive for total coliform.
For purposes of public notification requirements in subch. VI
, this is a violation that may pose an acute risk to health.
(2) Determining compliance.
The water supplier for a public water system shall determine compliance with the MCL for E. coli
in sub. (1)
for each monitoring period in which the public water system is required to monitor for total coliforms.
(3) Corrective action.
The water supplier shall initiate action to identify the cause of the positive bacteriological sample results and to eliminate potential health hazards which may exist in the public water system when monitoring pursuant to sub. (1)
shows the presence of any coliform organisms.
(4) heterotrophic bacteria limits.
If heterotrophic bacterial plate counts on water distributed to the consumer exceed 500 organisms per milliliter, the department shall determine if the bacterial count is of public health or nuisance significance and may require appropriate action.
(5) best available treatment techniques.
Any of the following are best technology, treatment techniques, or other means available for achieving compliance with the maximum contaminant level for E. coli
in sub. (1)
Protection of wells from fecal contamination by appropriate placement and construction.
Maintenance of a disinfectant residual throughout the distribution system.
Proper maintenance of the distribution system including appropriate pipe replacement and repair procedures, main flushing programs, proper operation and maintenance of storage tanks and reservoirs, cross connection control, and continual maintenance of positive water pressure in all parts of the distribution system.
Filtration and disinfection of surface water, or disinfection of groundwater using strong oxidants such as chlorine, chlorine dioxide or ozone.
The development and implementation of a department-approved wellhead protection program.
NR 809.30 Note
Note: The basic purpose of a wellhead protection program is to restrict potentially polluting activities near wells and well fields and within recharge areas of aquifers supplying water to these wells. In general, activities are more restricted close to the well and less so farther away.
(6) Affordability determination.
The EPA identifies the technology, treatment techniques, or other means available identified in sub. (5)
as affordable technology, treatment techniques, or other means available to systems serving 10,000 or fewer people for achieving compliance with the maximum contaminant level for E. coli
in sub. (1)
NR 809.30 History
History: CR 09-073
: cr. Register November 2010 No. 659
, eff. 12-1-10; correction in (4) made under s. 13.92 (4) (b) 7.
, Stats., Register November 2010 No. 659
; CR 15-049
: r. and recr. (1), r. (2), renum. (3) and (4) to (2) and (3) and am., renum. (5) to (4), renum. (6) to (5) and am. (intro.), (a), (c), cr. (6) Register March 2016 No. 723
, eff. 4-1-16; correction in (1) (b) made under s. 13.92 (4) (b) 7., Stats., Register December 2018 No. 756
Distribution system microbiological contaminant monitoring requirements. NR 809.31(1)(a)
Monitoring site plans.
Water suppliers for all public water systems shall collect total coliform samples at sites which are representative of water throughout the distribution system according to a written sample siting plan. These plans are subject to department review and revision. Monitoring required by this section and s. NR 809.32
may take place at a customer's premise, dedicated sampling station, or other designated compliance sampling location. Routine and repeat sample sites and any sampling points necessary to meet the requirements of s. NR 809.325
shall be identified in the sampling plan.
Action after total coliform positive sample.
Following any total coliform-positive sample taken under the provisions of this section, water suppliers shall comply with the repeat monitoring requirements and E. coli
analytical requirements in subs. (2)
Transition from total coliform rule to revised total coliform rule. NR 809.31(1)(ar)1.1.
Water suppliers of public water systems, including seasonal systems, shall continue to monitor according to the total coliform monitoring schedules that were in effect on March 31, 2016, unless any of the conditions for increased monitoring in sub. (3) (a)
are triggered on or after April 1, 2016, or unless otherwise directed by the department.
Beginning April 1, 2016, the department shall perform a special monitoring evaluation during each sanitary survey to review the status of each public water system, including the distribution system, to determine whether the public water system is on an appropriate monitoring schedule. After the department has performed the special monitoring evaluation during each sanitary survey, the department may modify the public water system's monitoring schedule, as necessary, or it may allow the public water system to stay on its existing monitoring schedule, consistent with the provisions of this section. The department may not allow public water systems to begin less frequent monitoring under the special monitoring evaluation unless the public water system has already met the applicable criteria for less frequent monitoring in this section. For seasonal systems on quarterly or annual monitoring, this evaluation shall include review of the approved sample siting plan, which shall designate the time period(s) for monitoring based on site-specific considerations (e.g., during periods of highest demand or highest vulnerability to contamination). The water supplier of the seasonal system shall collect compliance samples during these time periods.
Monitoring frequency at community water systems.
Water suppliers for community water systems shall take water samples for coliform determination at regular intervals, and in a number proportionate to the population served by the community water system. Water suppliers required to collect multiple samples each month shall sample at geographically representative locations and on dates evenly spaced during the month. The minimum sampling frequency shall be as set forth in the following table:
- See PDF for table
Monitoring frequency for coliforms at non-community water systems.
The monitoring frequency for total coliforms for non-community water systems, notwithstanding pars. (dg)
, is as follows:
A water supplier for a non-community water system using only groundwater and serving 1,000 persons per day or fewer shall monitor each calendar quarter that the non-community water system provides water to the public.
A water supplier for a non-community water system using only groundwater and serving on average more than 1,000 persons per day for any month shall monitor at the same frequency as a like-sized community water system, as specified in par. (b)
, except that the department may reduce the monitoring frequency, in writing, for any month the average daily population served is 1,000 persons or fewer per day.
A water supplier for a non-community water system using surface water, or groundwater under the direct influence of surface water as defined in s. NR 809.04 (40)
, in total or in part, shall monitor at the same frequency as a like-sized municipal community water system, as specified in par. (b)
. GWUDI public water systems shall begin monitoring at this frequency beginning 6 months after the department determines that the groundwater source is under the direct influence of surface water.
The water supplier for a transient non-community water system serving a school shall sample for coliform bacteria in each calendar quarter during which the public water system provides water to the public, unless the department, on the basis of sub. (2m)
, determines that more frequent monitoring is appropriate. Transient non-community systems serving schools are not eligible for reduced monitoring under par. (dg)
of this section.
Annual site visits.
Beginning no later than calendar year 2017, transient non-community systems on annual monitoring, including seasonal systems, shall have an initial and recurring annual site visit by the department that is equivalent to a Level 2 assessment or an annual voluntary Level 2 assessment that meets the criteria in s. NR 809.313 (2)
to remain on annual monitoring. The periodic required sanitary survey may be used to meet the requirement for an annual site visit for the year in which the sanitary survey was completed. Transient non-community systems with little-to-no distribution system may, at the discretion of the department, be exempt from the annual site visit requirements in this section, and still remain on annual monitoring.
Criteria for annual monitoring at transient non-community systems.
Beginning April 1, 2016, the department may reduce the monitoring frequency for a well-operated transient non-community ground water system serving 1,000 persons per day or fewer from quarterly routine monitoring to no less than annual monitoring, if the transient non-community system demonstrates that it meets the criteria for reduced monitoring in subds. 1.
, except for a transient non-community system that has been on increased monitoring under the provisions of sub. (2m)
. A transient non-community system on increased monitoring under sub. (2m)
shall meet the provisions of sub. (2m) (b)
to go to quarterly monitoring and shall meet the provisions of sub. (2m) (c)
to go to annual monitoring.
The transient non-community system has a clean compliance history for a minimum of 12 months.
The most recent sanitary survey shows that the transient non-community system is free of sanitary defects or has corrected all identified sanitary defects, has a protected water source, and meets approved construction standards.
The department has conducted an annual site visit within the last 12 months and the water supplier has corrected all identified sanitary defects. A Level 2 assessment that meets the criteria in s. NR 809.313 (2)
may be substituted for the department annual site visit.
Beginning April 1, 2016, all water suppliers of seasonal systems shall demonstrate completion of a department-approved start-up procedure, which may include a requirement for start-up sampling prior to serving water to the public.
Seasonal systems shall be monitored every month that they are in operation unless they meet the criteria in subd. 2. a.
to be eligible for monitoring less frequently than monthly beginning April 1, 2016, except as provided under par. (ar)
Seasonal systems that are monitored less frequently than monthly shall have an approved sample siting plan that designates the time period for monitoring based on site-specific considerations (e.g., during periods of highest demand or highest vulnerability to contamination). Water suppliers of seasonal systems shall collect compliance samples during this time period.
The department may exempt any seasonal system from some or all of the requirements for seasonal systems if the entire distribution system remains pressurized during the entire period that the seasonal system is not operating, except that seasonal systems that are monitored less frequently than monthly shall be monitored during the vulnerable period as designated by the department.
Sample collection time intervals.
Water suppliers for public water systems shall collect samples at regular time intervals throughout the month, except that for public water systems which use only groundwater and serve 4,900 persons or fewer, may collect all required samples on a single day if the samples are taken from different sites.
Minimum required number of samples after MCL violation or treatment technique trigger.
Water suppliers shall take at least the minimum number of required samples even if the public water system has had an E. coli
MCL violation or has exceeded the coliform treatment technique triggers in s. NR 809.313
Sampling in excess of requirements.
Water suppliers may conduct more compliance monitoring than is required by this section to investigate potential problems in the distribution system and use monitoring as a tool to assist in uncovering problems. Water suppliers may take more than the minimum number of required routine samples and shall include the results in calculating whether the coliform treatment technique trigger in s. NR 809.313
has been exceeded only if the samples are taken in accordance with the existing sample siting plan and are representative of water throughout the distribution system.
Special purpose samples.
Special purpose samples such as those taken to determine whether disinfection practices are sufficient following pipe placement, replacement or repair, may not be used to determine whether the coliform treatment technique trigger has been exceeded. Repeat samples taken pursuant to sub. (2)
are not considered special purpose samples, and shall be used to determine whether the coliform treatment technique trigger has been exceeded.
Analyses required after turbidity exceedances at selected systems.
A water supplier for a public water system that uses surface water or groundwater under the direct influence of surface water as defined in s. NR 809.04 (40)
, and does not provide filtration in compliance with s. NR 810.29
, shall collect at least one sample in the distribution system near the first service connection each day one or more turbidity measurements of the source water obtained as specified in s. NR 810.38 (1) (c)
, exceeds 1 NTU. This sample shall be analyzed for the presence of total coliforms. The water supplier shall collect this coliform sample within 24 hours of the first exceedance unless the department determines that the water supplier, for logistical reasons beyond their control, cannot have the sample analyzed within 30 hours of collection. Results from this coliform monitoring shall be used to determine whether the coliform treatment technique trigger has been exceeded in s. NR 809.313