Wisconsin Administrative Code
Department of Natural Resources
NR 800 - Environmental Protection - Water Supply
Chapter NR 809 - Safe Drinking Water
Subchapter I - Maximum Contaminant Levels, Monitoring and Analytical Requirements for Primary Drinking Water Contaminants
Section NR 809.205 - Monitoring requirements for synthetic organic contaminants

Universal Citation: WI Admin Code § NR 809.205

Current through August 26, 2024

(1) GENERAL. Water suppliers for community and non-transient non-community water systems shall monitor for the synthetic organic contaminants listed in s. NR 809.20 for the purposes of determining compliance with the maximum contaminant levels as follows:

(a) Groundwater sources shall be sampled under normal operating conditions at every entry point to the distribution system which is representative of each well after treatment. Each sample shall be taken at the same location unless, if approved by the department, conditions make another sampling location more representative of each source or treatment plant.

(b) Surface water sources or combined surface water and groundwater sources shall be sampled at each entry point to the distribution system after treatment, or at locations in the distribution system that are representative of each source after treatment. Each sample shall be taken at the same sampling location unless, if approved by the department, conditions make another sampling location more representative of each source or treatment plant.

(c) If the public water system draws water from more than one source and the sources are combined before distribution, the public water system shall be sampled at an entry point to the distribution system during periods of normal operating conditions when water representative of all sources is being used.

(d) The water supplier for all new public water systems or for public water systems that use a new source of water that begin operation after January 22, 2004 shall demonstrate compliance with the MCLs specified in s. NR 809.20 in accordance with the requirements in this section. The water supplier shall also comply with the initial sampling frequencies specified by the department to ensure the public water system can demonstrate compliance with the MCLs. Routine and increased monitoring frequencies shall be conducted in accordance with the requirements of this section.

(1g) SCHEDULE FOR PERFLUOROOCTANE SULFONIC ACID AND PERFLUOROOCTANOIC ACID MONITORING.

(a) Community and non-transient non-community public water systems serving a population of 50,000 or more shall comply with initial monitoring requirements under sub. (1r) (a) for perfluorooctane sulfonic acid and perfluorooctanoic acid beginning on November 1, 2022.

(b) Community and non-transient non-community public water systems serving a population of 10,000 to 49,999 shall comply with initial monitoring requirements under sub. (1r) (a) for perfluorooctane sulfonic acid and perfluorooctanoic acid beginning on February 1, 2023.

(c) Community and non-transient non-community public water systems serving a population of less than 10,000 shall comply with initial monitoring requirements under sub. (1r) (a) for perfluorooctane sulfonic acid and perfluorooctanoic acid beginning on May 1, 2023.

(1r) MONITORING FREQUENCY FOR PERFLUOROOCTANE SULFONIC ACID AND PERFLUOROOCTANOIC ACID. Water suppliers shall monitor to determine compliance with the maximum contaminant level for perfluorooctane sulfonic acid and perfluorooctanoic acid at the following frequencies:

(a) Initial monitoring. Water suppliers for new community public water systems or for community public water systems with new sources shall demonstrate compliance with the MCLs prior to initiating water service. Water suppliers for each community and non-transient, non-community water system shall take 4 consecutive quarterly samples for perfluorooctane sulfonic acid and perfluorooctanoic acid beginning on the dates specified under sub. (1g) or beginning with the year the public water system initiates water service, or a new source is put into service, and every compliance period thereafter unless the requirements of pars. (b) and (c) are met.

(b) Initial waiver evaluation. For perfluorooctane sulfonic acid and perfluorooctanoic acid the department may waive the final 2 quarters of initial monitoring for a sampling point if the results of the samples from the previous 2 quarters are below the detection limit.

1. 'Public water systems serving greater than 3,300.' Public water systems serving more than 3,300 persons that do not detect a contaminant in the initial compliance period or during 3 consecutive years of annual monitoring may reduce the sampling frequency to a minimum of 2 quarterly samples in one year during each repeat compliance period.

2. 'Public water systems serving 3,300 or less.' Public water systems serving 3,300 persons or less that do not detect a contaminant in the initial compliance period or during 3 consecutive years of annual monitoring may reduce the sampling frequency to a minimum of one sample during each repeat compliance period.

(d) Waiver request. Water suppliers for community and non-transient non-community systems may apply to the department for a waiver from the requirements under pars.

(a) and

(c) for perfluorooctane sulfonic acid and perfluorooctanoic acid. A water supplier shall reapply for a waiver for each compliance period. The waiver period shall not exceed 2 compliance periods.

(e) Waiver evaluation. The department may grant a waiver from the requirements under pars. (a) and (c) after evaluating all of the following factors:

1. 'Waiver evaluation when the department determines a contaminant has not been used.' The department may grant a waiver when the department determines a contaminant has not been used based on a system's previous use information, including transport, storage, or disposal of the contaminant within the watershed or zone of influence of the public water system, or the results of analysis of a system's water source.

2. 'Waiver evaluation when a contaminant has been used or its use is unknown.' If previous use of the contaminant is unknown or it has been used previously, all of the following factors shall be used to determine whether a waiver is granted:

a. Previous analytical results.

b. The proximity of the public water system to a potential point source of contamination. Point sources include spills and leaks of chemicals at or near a water treatment facility or at manufacturing, distribution, or storage facilities, or from hazardous and municipal waste landfills and other waste handling or treatment facilities; or at airports, military bases, and fire training facilities.

(f) Waiver conditions and monitoring assessments. As a condition of the waiver under par. (e), the water supplier for a groundwater system shall update the monitoring assessment considering the factors listed under par. (e). Based on this updated monitoring assessment, the department shall reconfirm that the public water system is non-vulnerable. If the department does not make this reconfirmation within 3 years of the initial determination or each subsequent determination, then the waiver is invalidated, and the public water system is required to sample during each compliance period as specified under par. (c).

(2) MONITORING FREQUENCY FOR SYNTHETIC ORGANIC CONTAMINANTS OTHER THAN PERFLUOROOCTANE SULFONIC ACID AND PERFLUOROOCTANOIC ACID. Water suppliers shall monitor to determine compliance with the maximum contaminant level for synthetic organic contaminants other than perfluorooctane sulfonic acid and perfluorooctanoic acid listed under s. NR 809.20 at the following frequencies:

(a) Initial monitoring. Water suppliers for new community public water systems or for community public water systems with new sources shall demonstrate compliance with the MCLs listed under s. NR 809.20 for synthetic organic contaminants other than perfluorooctane sulfonic acid and perfluorooctanoic acid prior to initiating water service. Water suppliers for each community and non-transient, non-community water system shall take 4 consecutive quarterly samples for each contaminant listed under s. NR 809.20, other than perfluorooctane sulfonic acid and perfluorooctanoic acid, beginning with the year the public water system initiates water service, or a new source is put into service, and every compliance period after that unless they meet the requirements under par. (b).

(b) Routine monitoring. Initial quarterly sampling under sub. (2) (a) may be reduced to routine monitoring after the initial monitoring period as follows:

1. 'Public water systems serving greater than 3,330.' Public water systems serving more than 3,300 persons that do not detect a contaminant in the initial compliance period or during 3 consecutive years of annual monitoring may reduce the sampling frequency to a minimum of 2 quarterly samples in one year during each repeat compliance period.

(c) Waiver request. Water suppliers for community and non-transient non-community systems or groundwater systems with new sources may apply to the department for a waiver from the requirements of pars. (a) and (b) for the synthetic organic contaminants other than perfluorooctane sulfonic acid and perfluorooctanoic acid listed under s. NR 809.20. A water supplier shall reapply for a waiver for each compliance period.

(d) Waiver evaluation. The department may grant a waiver from the requirements of this subsection after evaluating all of the following factors:

1. 'Waiver evaluation when the department determines a contaminant has not been used.' The department may grant a waiver as described in this subdivision and subd. 2. of this paragraph under the following circumstances when the department determines a contaminant has not been used based on a system's previous use information, including transport, storage, or disposal of the contaminant within the watershed or zone of influence of the public water system, or the results of analysis of a system's water source:

a. When a groundwater system can demonstrate that a synthetic organic contaminant has not been used, the department may grant waivers for the contaminant based on results of the analysis of a minimum of one sample at the water source, except as noted under subd. 1. b.

b. The department may grant waivers to ground water systems for dioxin, PCBs, di(2-ethylhexyl)adipate, and di(2-ethylhexyl)phthalate without requiring analysis of the water source, if the system can demonstrate lack of use of the contaminant.

c. The department may grant waivers for benzo(a)pyrene to ground water, surface water, and GWUDI systems without requiring analysis of the water source, if the system can demonstrate a lack of use of coal tar to line or seal a system's tanks or pipes.

2. 'Waiver evaluation when a contaminant has been used or its use is unknown.' If previous use of the contaminant is unknown or it has been used previously, then all of the following factors shall be used to determine whether a waiver is granted:

a. Previous analytical results.

b. The proximity of the public water system to a potential point or non-point source of contamination. Point sources include spills and leaks of chemicals at or near a water treatment facility or at manufacturing, distribution, or storage facilities, or from hazardous and municipal waste landfills and other waste handling or treatment facilities. Non-point sources include the use of pesticides to control insect and weed pests on agricultural areas, forest lands, home and gardens, and other land application uses.

c. The environmental persistence and transport of the pesticide or PCBs.

d. How well the water source is protected against contamination due to such factors as depth of the well and the type of soil and the integrity of the well casing.

e. Elevated nitrate levels at the water supply source.

f. Use of PCBs in equipment used in the production, storage or distribution of water such as pumps and transformers.

(e) Waiver conditions and monitoring assessments. As a condition of the waiver under par. (d), the water supplier for a groundwater system shall update the monitoring assessment considering the factors listed under par. (d). Based on this monitoring assessment, the department shall reconfirm that the public water system is non-vulnerable. If the department does not make this reconfirmation within 3 years of the initial determination or each subsequent determination, then the waiver is invalidated and the public water system is required to sample during each compliance period as specified under par. (b).

(6) MONITORING FOR DETECTED CONTAMINANTS. If a synthetic organic contaminant listed in s. NR 809.20 is detected, as provided by s. NR 809.203 (1) in any sample, then the water supplier shall monitor quarterly at each entry point which resulted in detection. Quarterly monitoring may be modified by the department as follows:

(a) The department may decrease the quarterly monitoring requirement specified in par. (a) provided it has determined that the public water system is reliably and consistently below the MCL. In no case may the department make this determination unless a groundwater system has been monitored in a minimum of 2 quarters and a surface water system has been monitored in a minimum of 4 quarters.

(b) After the department determines the public water system is reliably and consistently below the MCL, the department may allow the public water system to be monitored annually. Public water systems which are monitored annually shall be monitored during the quarter that previously yielded the highest analytical results.

(c) Water suppliers for public water systems that have 3 consecutive annual samples with no detection of a contaminant may apply to the department for reduced routine monitoring as specified under subs. (1) (c) and (2) (b) or a waiver as specified under subs. (1) (d) and (e) and (2) (c) and (d).

(d) If monitoring results in detection of one or more of certain related contaminants such as heptachlor and heptachlor epoxide, then subsequent monitoring shall analyze for all related contaminants.

(7) MONITORING WHEN AN MCL IS EXCEEDED. Additional monitoring for synthetic organic contaminants shall be required as follows in order to maintain compliance:

(a) If an organic contaminant listed in s. NR 809.20 is detected at a level exceeding the MCL in any sample, then the water supplier shall begin to take quarterly samples at each entry point which exceeded an MCL.

(b) Public water systems which exceed an MCL listed in s. NR 809.20 as determined by s. NR 809.207 (1) shall be monitored quarterly. After a minimum of 4 quarterly samples show that the public water system is back in compliance and the department determines the public water system is reliably and consistently below the MCL as specified in s. NR 809.207 (1), the public water system shall be monitored at the frequency specified in sub. (6) (b).

(8) CONFIRMATION SAMPLES. The department may require a confirmation sample for positive or negative results. If a confirmation sample is required by the department, the result shall be averaged with the first sampling result and the average used for the compliance determination as specified by s. NR 809.207 (1). The department may delete results of obvious sampling errors from this calculation, or may require additional samples to determine whether the result is or is not in error.

(9) COMPOSITE SAMPLING. The department may reduce the total number of samples a public water system is required to analyze by allowing the use of compositing. If the department allows compositing, the following composite sampling requirements shall be met:

(a) Composite samples from a maximum of 5 entry points are allowed, if the detection limit of the method used for analysis is less than one-fifth of the MCL. Compositing is only permitted at entry points within a single public water system. Compositing of samples shall be done in the laboratory and analyzed within 14 days of sample collection.

(b) If the concentration in the composite sample detects one or more contaminants listed in s. NR 809.20, then a follow-up sample shall be taken and analyzed for each contaminant detected within 14 days from each entry point included in the composite.

(c) If duplicate aliquots of the original sample taken from each entry point used in the composite are available, the public water system may use these duplicates instead of re-sampling. The duplicate shall be analyzed and the results reported to the department within 14 days of collection.

(10) INCREASING MONITORING FREQUENCY. The department may increase the required monitoring frequency, if necessary, to detect variations within the public water system. Examples of variations include fluctuations in concentration due to seasonal use or changes in the water source.

(11) DESIGNATION OF SAMPLING TIMES. Each public water system shall be monitored during the month, quarter or year designated by the department within each compliance period.

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