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. (2m) are triggered on or after April 1, 2016, or unless otherwise directed by the department.

NR 809.31(1)(ar)2.2. 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.

NR 809.31(1)(b)(b) 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:

NR 809.31(1)(c)1.1. 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.

NR 809.31(1)(c)2.2. 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.

NR 809.31(1)(c)3.3. 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.

NR 809.31(1)(c)4.4. 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.

NR 809.31(1)(de)(de) 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.

NR 809.31(1)(dg)(dg) 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. to 4., 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.

NR 809.31(1)(dg)1.1. The transient non-community system has a clean compliance history for a minimum of 12 months.

NR 809.31(1)(dg)2.2. 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.

NR 809.31(1)(dg)3.3. 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.

NR 809.31(1)(dg)4.4. The public water system is not a school.

NR 809.31(1)(dr)1.1. 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.

NR 809.31(1)(dr)2.2. Seasonal systems shall be monitored every month that they are in operation unless they meet the criteria in subd. 2. a. to c. to be eligible for monitoring less frequently than monthly beginning April 1, 2016, except as provided under par. (ar).

NR 809.31(1)(dr)2.a.a. 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.

NR 809.31(1)(dr)3.3. 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.

NR 809.31(1)(e)(e) 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.

NR 809.31(1)(eg)(eg) 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.

NR 809.31(1)(er)(er) 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.

NR 809.31(1)(f)(f) 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.

NR 809.31(1)(g)(g) 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.

NR 809.31(2)(a)(a) If a routine sample is total coliform-positive, the water supplier for a public water system shall collect a set of repeat samples within 24 hours of being notified of the positive result. The water supplier shall collect no fewer than 3 repeat samples for each total coliform-positive sample found. The department may extend the 24-hour limit on a case-by-case basis if the water supplier has a logistical problem that is beyond its control in collecting the repeat samples within 24 hours. In the case of an extension, the department shall specify how much time the water supplier has to collect repeat samples. The department may not waive the requirement for a water supplier to collect repeat samples in this paragraph or pars. (b) to (c).