NR 809.31(2m)(c)2.
2. The water supplier shall have in place or adopt one or more additional enhancements to the water system barriers to contamination in subds.
2. a. to
2. e. NR 809.31(2m)(c)2.c.
c. Continuous disinfection entering the distribution system and a residual in the distribution system in accordance with criteria specified by the department.
NR 809.31(2m)(c)2.e.
e. Other equivalent enhancements to public water system barriers to contamination as approved by the department.
NR 809.31(2m)(d)
(d)
Allowance for transient non-community water systems to monitor annually. The department may allow water suppliers at transient non-community water systems to monitor annually for total coliform and
E. coli following conditions that would require increased monitoring under par.
(a), provided the water supplier meets the requirements of subd.
1. or
2. NR 809.31(2m)(d)1.
1. For water systems that began operation and conducted coliform monitoring prior to April 1, 2016, the water supplier shall have done all of the following:
NR 809.31(2m)(d)1.a.
a. Completed all required total coliform monitoring in the previous calendar year.
NR 809.31(2m)(d)1.c.
c. Corrected all significant deficiencies or is following a department agreed upon schedule for correcting all significant deficiencies.
NR 809.31(2m)(d)1.d.
d. Received a level 2 assessment within 30 days of any level 1 assessment trigger identified after April 1, 2016, and corrected all sanitary defects or is following a department agreed upon schedule for correcting all sanitary defects.
NR 809.31(2m)(d)1.e.
e. Completed all repeat sampling requirements associated with any total coliform positive identified after April 1, 2016.
NR 809.31(2m)(d)2.
2. For public water systems that began operation or began coliform monitoring on or after April 1, 2016, the water supplier shall meet all of the requirements of subd. 1 and shall have completed at least one year of coliform monitoring at a frequency of no less than quarterly.
NR 809.31(2m)(e)
(e)
Allowance for non-transient non-community water systems to monitor quarterly. The department may allow a water supplier of a non-transient non-community water system to monitor quarterly for total coliform and
E. coli following conditions that would require increased monitoring under par.
(a), provided the water supplier meets the same requirements specified for transient non-community water systems in par.
(d) 1. a. to
f. NR 809.31(3)(a)
(a) A total coliform-positive sample invalidated under this subsection does not count towards meeting the minimum monitoring requirements of this section.
NR 809.31(3)(b)
(b) The department may invalidate a total coliform-positive sample only if the conditions of subd.
1.,
2. or
3. are met.
NR 809.31(3)(b)1.
1. A certified laboratory establishes that improper sample analysis caused the total coliform-positive result.
NR 809.31(3)(b)2.
2. The department, on the basis of the results of repeat samples collected as required by sub.
(2) (a) to
(e), determines that the total coliform-positive sample resulted from a domestic or other non-distribution system plumbing problem. A sample may not be invalidated by the department on the basis of repeat sample results alone, unless all repeat samples collected at the same tap as the original total coliform-positive sample are also total coliform-positive, and all repeat samples collected at a location other than the original tap are total coliform-negative. The department will not invalidate a total coliform-positive sample on the basis of repeat samples if all the repeat samples are total coliform-negative, or if the public water system has only one service connection.
NR 809.31(3)(b)3.
3. The department has substantial grounds to believe that a total coliform-positive result is due to a circumstance or condition which does not reflect water quality in the distribution system. In this case, the water supplier shall still collect all repeat samples required, and shall use them to determine whether a coliform treatment technique trigger in s.
NR 809.313 has been exceeded. To invalidate a total coliform-positive sample under this paragraph, the decision with the rationale for the decision shall be documented in writing, approved by a qualified department official and available to the public for inspection. The document shall state the specific cause of the total coliform-positive sample, and what action the water supplier has taken or will take, to correct this problem. The department may not invalidate a total coliform-positive sample solely on the grounds that all repeat samples are total coliform-negative.
NR 809.31(3)(c)
(c) A laboratory shall invalidate a total coliform sample if the sample produces a turbid culture in the absence of gas production using an analytical method where gas formation is examined for, example, the Multiple Tube Fermentation Technique, produces a turbid culture in the absence of an acid reaction in the Presence-Absence Coliform Test, or exhibits confluent growth or produces colonies too numerous to count with an analytical method using a membrane filter, for example, Membrane Filter Technique, except that a laboratory shall not invalidate a total coliform sample if total coliforms are detected. If a laboratory invalidates a sample because of such interference, the water supplier shall collect another sample from the same location as the original sample within 24 hours of being notified of the interference problem, and have it analyzed for the presence of total coliforms. The water supplier shall continue to re-sample every 24 hours and have the samples analyzed until a valid result is obtained. The department may waive the 24 hour time limit on a case-by-case basis. Alternatively, the department may implement criteria for waiving the 24-hour sampling time limit to use in lieu of case-by-case extensions.
NR 809.31(4)(a)
(a) If any routine or repeat sample is total coliform-positive, the water supplier shall analyze that total coliform-positive culture medium to determine if
E. coli are present. If
E. coli are present, the water supplier shall notify the department by the end of the day when the water supplier is notified of the test result, unless the water supplier is notified of the result after normal department business hours, in which case the water supplier shall notify the department before the end of the next business day.
NR 809.31(4)(b)
(b) The department may allow a water supplier for a public water system, on a case-by-case basis, to forgo
E. coli testing on a total coliform-positive sample if that water supplier assumes that the total coliform-positive sample is
E. coli positive. Accordingly, the water supplier shall notify the department as specified in par.
(a) and the provisions of s.
NR 809.30 (2) apply.
NR 809.31(5)
(5)
Groundwater system raw water sampling. In addition to sampling from the distribution system, each water supplier for a public water system providing disinfection shall obtain at least one sample every 3 months from each well prior to the point of treatment. For public water systems which have more than one well in the same location and utilizing the same aquifer, the supplier of water may sample only one of the wells each time on an alternating basis. If a well has a high potential for contamination, the department may, in individual cases, require more frequent sampling.
NR 809.31(6)
(6)
Surface water system raw water sampling. At surface water facilities, the microbiological quality of the source water shall be monitored sufficiently to maintain quality control of the treatment process. Water suppliers shall establish a schedule for each plant, subject to review and modification by the department.
NR 809.31 Note
Note: Generally, enumeration methods such as membrane filter, numeric enzyme substrate, or 5 tube fermentation tests and heterotrophic plate counts of the raw, settled and finished water on an established schedule will be necessary to meet this requirement.
NR 809.31(7)
(7)
Heterotrophic plate counts. At all waterworks which have a potential for high total bacteria levels because of the water quality, the method of treatment, chemical addition or other cause, the department may require heterotrophic plate counts pursuant to an established schedule. Analyses shall be conducted in accordance with the analytical requirements in s.
NR 809.311 (1), Table F.
NR 809.31(9)(a)(a) Failure to take every required routine or additional routine sample in a compliance period is a monitoring violation.
NR 809.31(9)(b)
(b) Failure to analyze for
E. coli following a total coliform-positive routine sample is a monitoring violation.
NR 809.31(10)(a)(a) Failure to submit a monitoring report or completed assessment form after a water supplier properly conducts monitoring or assessment in a timely manner is a reporting violation.
NR 809.31(10)(b)
(b) Failure to notify the department following an
E. coli-positive sample as required by sub.
(4) in a timely manner is a reporting violation.
NR 809.31(10)(c)
(c) Failure to submit certification of completion of department-approved start-up procedure by a seasonal system is a reporting violation.
NR 809.31 History
History: CR 09-073: cr.
Register November 2010 No. 659, eff. 12-1-10;
CR 15-049: am. (1) (title), (a), cr. (1) (ag), (ar), renum. (1) (b) 1. to (b) and am., r. (1) (b) 2., renum. (1) (c) to (d) 4. and am., renum. (1) (d) to (c) and am., cr. (1) (de), (dg), (dr), am. (1) (e), cr. (1) (eg), (er), am. (1) (f), (g), (2) (a), renum. (2) (b) to (b) (intro.) and am., cr. (2) (b) 1. to 3., am. (2) (c) to (e), r. and recr. (2) (f) (intro.), am. (2) (f) 1., 2., cr. (2) (f) 3., am. (2) (h), cr. (2m), am. (3) (b) 2., 3., (c), (4) to (6), cr. (9), (10)
Register March 2016 No. 723, eff. 4-1-16; corrections in (1) (d) 2. (intro.), (2) (a) (intro.), (b) (intro.), (f) (intro.), (2m) (d) (intro.), (e), (3) (b) 2. made under s.
35.17, Stats.,
Register March 2016 No. 723; correction in (1) (ag), (ar) made under s.
13.92 (4) (b) 7., Stats.,
Register July 2022 No. 799.
NR 809.311
NR 809.311 Analytical requirements for microbiological contaminants. NR 809.311(1)(1)
Analytical methods. Analyses conducted to determine compliance with s.
NR 809.31 shall be made in accordance with methods listed in Table F.
NR 809.311(2)
(2)
Sample volume. The standard sample volume required for total coliform analysis, regardless of analytical method used, is 100 ml.
NR 809.311(3)
(3)
Sample collection preservation and holding time. NR 809.311(3)(a)
(a) Sample collection for microbiological contaminants under s.
NR 809.30 shall be conducted using the sample preservation, containers and maximum holding time procedures specified in par.
(b).
NR 809.311(3)(b)
(b) Sample preservation requirements and holding times for microbiological samples
are specified in subds.
1. and
2. In all cases, samples shall be analyzed as soon after collection as possible.
NR 809.311(3)(b)1.
1. Total Coliform and
E. coli samples are not required to be preserved by cooling to 10
° C, however it is encouraged during transit. Sodium thiosulfate shall be added to the sample container prior to adding water containing chlorine and the holding time shall be 30 hours.
NR 809.311(3)(b)2.
2. Heterotrophs may be either held at room temperature with a holding time of 6 hours or preserved by cooling to 4
° C with a holding time of 24 hours.
NR 809.311(4)
(4)
Laboratory certification. Analyses under this section shall only be conducted by laboratories that have received certification under ch.
ATCP 77 or approval by EPA.
NR 809.311(5)
(5)
Presence or absence. Water suppliers need only determine the presence or absence of total coliforms; a determination of total coliform density is not required.
NR 809.311 Note
Note: The coliform density may, however, be helpful in selecting a remedial option.
NR 809.311(6)
(6)
Required methods. Samples collected to determine compliance with s.
NR 809.30 (1) shall be analyzed by enzyme substrate test methods.
NR 809.311(7)
(7)
Other methods. The department may approve, on a case-by-case basis, other methods for use in determining compliance with s.
NR 809.30 (1) if they have been approved by EPA.
NR 809.311(8)
(8)
Sample integrity. If chlorine odor is present in a drinking water sample the laboratory shall test the sample for the presence of chlorine. If chlorine is detected in the sample, the laboratory shall reject the sample for analysis, based on the improper preservation. The water supplier shall submit a new sample for analysis to replace the rejected sample.
-
See PDF for table 
1 Standard Methods for the Examination of Water and Wastewater, 20th edition (1998). Available from American Public Health Association, 800 I Street, NW., Washington, DC 20001-3710.
2 Standard Methods for the Examination of Water and Wastewater, 21st edition (2005). Available from American Public Health Association, 800 I Street, NW., Washington, DC 20001-3710.
3 Standard Methods for the Examination of Water and Wastewater, 22nd edition (2012). Available from American Public Health Association, 800 I Street NW., Washington, DC 20001-3710.
4
Standard Methods Online are available at http://www.standardmethods.org. The year in which each method was approved by the Standard Methods Committee is designated by the last two digits in the method number. The methods listed are the only online versions that may be used.
5 Lactose broth, as commercially available, may be used in lieu of lauryl tryptose broth, if the system conducts at least 25 parallel tests between lactose broth and lauryl tryptose broth using the water normally tested, and if the findings from this comparison demonstrate that the false-positive rate and false-negative rate for total coliforms, using lactose broth, is less than 10 percent.
6 A multiple tube enumerative format, as described in Standard Methods for the Examination of Water and Wastewater 9221, is approved for this method for use in presence-absence determination under this regulation.
7 EPA Method 1604, EPA 821-R-02-024—“EPA Method 1604: Total Coliforms and
Escherichia coli in Water by Membrane Filtration Using a Simultaneous Detection Technique (MI Medium)," September 2002,
http://www.epa.gov/nerlcwww/1604sp02.pdf.
8 Multiple-tube and multi-well enumerative formats for this method are approved for use in presence-absence determination under this regulation.
9 Colisure® results may be read after an incubation time of 24 hours.
10 E*Colite®—“Charm E*ColiteTM Presence/Absence Test for Detection and Identification of Coliform Bacteria and Escherichia coli in Drinking Water," January 9, 1998.
11 Readycult®—“Readycult® Coliforms 100 Presence/Absence Test for Detection and Identification of Coliform Bacteria and Escherichia coli in Finished Waters," January 2007, Version 1.1. Available from EMD Millipore (division of Merck KGaA, Darmstadt, Germany), 290 Concord Road, Billerica, MA 01821.
12 modified Colitag
®, ATP D05-0035—“Modified Colitag
TM Test Method for the Simultaneous Detection of
E. coli and other Total Coliforms in Water," August 28, 2009. Available at
http://www.nemi.gov or from CPI, International, 580 Skylane Boulevard, Santa Rosa, CA 95403.
NR 809.311 History
History: CR 09-073: cr.
Register November 2010 No. 659, eff. 12-1-10;
CR 15-049: am. (3) (b) 1., (6), (7), r. and recr. Table F
Register March 2016 No. 723, eff. 4-1-16.
NR 809.312
NR 809.312 Compliance reporting for microbiological contaminants. NR 809.312(1)(1)
MCL violation reporting. When a sample collected under s.
NR 809.31 (1),
(2),
(2m),
(4), or
(5) exceeds maximum contaminant level in s.
NR 809.30 (1), the water supplier shall report the violation to the department no later than the end of the next business day after it learns of the violation, and shall provide public notice of the violation in accordance with s.
NR 809.951.
NR 809.312(1m)
(1m)
treatment technique violation reporting. The water supplier for a public water system that has violated the treatment technique for coliforms in s.
NR 809.313 shall report the violation to the department by no later than the end of the next business day after it learns of the violation, and shall provide public notice of the violation in accordance with s.
NR 809.952.
NR 809.312(2)
(2)
Monitoring violation reporting. A water supplier who has failed to comply with a coliform monitoring requirement shall report the monitoring violation to the department within 10 days after discovering the violation, and shall notify the public as specified in s.
NR 809.953.
NR 809.312 History
History: CR 09-073: cr.
Register November 2010 No. 659, eff. 12-1-10;
CR 15-049: am. (1), cr. (1m)
Register March 2016 No. 723, eff. 4-1-16; correction in (2) made under s.
13.92 (4) (b) 7.,
Register July 2022 No. 799.
NR 809.313
NR 809.313 Coliform treatment technique triggers and assessment requirements for protection against potential fecal contamination. NR 809.313(1)(1)
Treatment technique triggers. Water suppliers of public water systems shall conduct assessments in accordance with sub.
(2) after public water systems exceed treatment technique triggers in par.
(a) or
(b).
NR 809.313(1)(a)1.
1. For public water systems taking 40 or more samples per month, the public water system exceeds 5.0% total coliform-positive samples for the month.
NR 809.313(1)(a)2.
2. For public water systems taking fewer than 40 samples per month, the public water system has two or more total coliform-positive samples in the same month.
NR 809.313(1)(a)3.
3. The water supplier fails to take every required repeat sample after any single total coliform-positive sample.
NR 809.313(1)(b)2.
2. A second Level 1 trigger as defined in par.
(a) within a rolling 12-month period, unless the department has determined a likely reason that the samples that caused the first Level 1 treatment technique trigger were total coliform-positive and has established that the water supplier has corrected the problem.
NR 809.313(1)(b)3.
3. For public water systems with approved annual monitoring, a Level 1 trigger in two consecutive years.
NR 809.313(2)(a)1.1. Water suppliers shall ensure that Level 1 and 2 assessments are conducted in order to identify the possible presence of sanitary defects, and defects in distribution system coliform monitoring practices. Level 2 assessments shall be conducted by parties approved by the department.
NR 809.313(2)(a)2.
2. When conducting assessments, water suppliers shall ensure that the assessor evaluates minimum elements that include review and identification of inadequacies in sample sites; sampling protocol; sample processing; atypical events that could affect distributed water quality or indicate that distributed water quality was impaired; changes in distribution system maintenance and operation that could affect distributed water quality, including water storage; source and treatment considerations that bear on distributed water quality, where appropriate, as for example, small ground water systems; and existing water quality monitoring data. The water supplier shall conduct the assessment consistent with any department directives that tailor specific assessment elements with respect to the size and type of the public water system and the size, type, and characteristics of the distribution system.
NR 809.313(2)(b)
(b)
Level 1 assessments. A water supplier shall conduct a Level 1 assessment consistent with department requirements if the public water system exceeds one of the treatment technique triggers in sub.
(1) (a).
The department may conduct a Level 2 assessment in response to a Level 1 treatment technique trigger at a non-community water system, which may include the collection of a large-volume sample.
NR 809.313(2)(b)1.
1. The water supplier shall complete a Level 1 assessment as soon as practical after any trigger in sub.
(1) (a). In the completed assessment form, the water supplier shall describe sanitary defects detected, corrective actions completed, and a proposed timetable for any corrective actions not already completed. The assessment form may also note that no sanitary defects were identified. The water supplier shall submit the completed Level 1 assessment form to the department within 30 days after the water supplier learns that the public water system has exceeded a trigger.
NR 809.313(2)(b)2.
2. If the department reviews the completed Level 1 assessment and determines that the assessment is not sufficient, including any proposed timetable for any corrective actions not already completed, the department shall consult with the water supplier. If the department requires revisions after consultation, the water supplier shall submit a revised assessment form to the department on an agreed-upon schedule not to exceed 30 days from the date of the consultation.
NR 809.313(2)(b)3.
3. Upon completion and submission of the assessment form by the water supplier, the department shall determine if the water supplier has identified a likely cause for the Level 1 trigger and, if so, establish that the water supplier has corrected the problem, or has included a schedule acceptable to the department for correcting the problem.
NR 809.313(2)(c)
(c)
Level 2 assessments. A water supplier shall ensure that a Level 2 assessment consistent with department requirements is conducted if the public water system exceeds one of the treatment technique triggers in sub.
(1) (b). The water supplier shall comply with any expedited actions or additional actions required by the department in the case of an
E. coli MCL violation.
