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 809.327 - Compliance requirements for groundwater source microbiological monitoring

Universal Citation: WI Admin Code § NR 809.327

Current through August 26, 2024

(1) COMPLIANCE REQUIREMENTS. Treatment technique submittal requirements for water suppliers for public water systems with significant deficiencies or confirmed source water fecal contamination are as follows:

(a) No later than 30 days after receiving written notice from the department of significant deficiencies, or notified by a laboratory of source water fecal contamination, water suppliers for groundwater systems shall consult with the department regarding appropriate corrective action, unless the department directs the water supplier to implement a specific corrective action.

(b) If the department specifies interim measures for protection of the public health, pending department approval of the corrective action plan and schedule or pending completion of the corrective action plan, the water supplier shall comply with these interim measures in addition to the other requirements of this section.

(c) No later than 120 days after receiving written notification from the department of a significant deficiency, or notified by a laboratory of confirmed source water fecal contamination, the water supplier for a groundwater system shall have one of the following:

1. A completed corrective action in accordance with the applicable department plan review processes contained in ch. NR 811 for community systems or ch. NR 812 for noncommunity systems.

2. A written and approved department corrective action plan and schedule.

(2) CORRECTIVE ACTION ALTERNATIVES. A water supplier for a groundwater systems receiving written notice from the department of significant deficiencies under s. NR 809.35 or confirmed source water fecal contamination under s. NR 809.325 shall implement one or more of the following corrective action alternatives:

(a) Correct all significant deficiencies.

(b) Provide an alternate source of water.

(d) Provide treatment that reliably achieves at least 4-log treatment of viruses before or at the first customer for the groundwater source.

(3) NOTIFICATION AND SUBMITTAL REQUIREMENTS FOR SYSTEMS PROVIDING 4 LOG TREATMENT OF VIRUSES.

(a) A public water system that has an existing or new groundwater source and serves customers on or after November 30, 2009 and provides department-approved treatment that achieves 4 log inactivation or removal of viruses before the first customer, is not required to meet the triggered source water monitoring requirements of s. NR 809.325(2) if all of the following conditions are met:

1. The water supplier notifies the department in writing that the public water system provides at least 4-log treatment of viruses.

2. The notification from the water supplier to the department shall include a submittal for review that includes the engineering and operational information that the department will need to evaluate the adequacy of the treatment.

3. The water supplier provides any other information that the department requests to aid in its evaluation of the sufficiency of the public water system's treatment process for viruses.

(b) A water supplier for a public water system that provides at least 4-log treatment of viruses before or at the first customer and places a new groundwater source into service after November 30, 2009, is not required to meet the triggered source water monitoring requirements of s. NR 809.325 if the water supplier complies with all of the following requirements:

1. The water supplier notifies the department in writing that it provides at least 4-log treatment of viruses before or at the first customer for the groundwater source.

2. The notification the water supplier provides to the department shall include an engineering, operational, or other information that the department requests to evaluate the submission.

3. The water supplier conducts compliance monitoring as required under sub. (4) within 30 days of placing the source in service.

(c) If a water supplier for a public water system subsequently discontinues 4-log treatment of viruses before or at the first customer for a groundwater source, the water supplier shall conduct triggered source water monitoring in accordance with the requirements of s. NR 809.325(2).

(4) TREATMENT COMPLIANCE MONITORING. A groundwater system that provides 4 log treatment of viruses shall monitor the effectiveness and reliability of treatment for that groundwater source before or at the first customer as follows:

(a) Chemical disinfection.

1. All water suppliers for community water systems shall continuously monitor the residual disinfectant concentration using analytical methods and requirements specified in s. NR 809.563 at a location approved by the department and shall record the lowest residual disinfectant concentration each day that water from the groundwater source is served to the public, unless the department allows less frequent monitoring as outlined in subd. 2.

a. The groundwater system shall maintain the department determined residual disinfectant concentration every day the public water system serves water from the groundwater source to the public.

b. If there is a failure in the continuous monitoring equipment, the water supplier shall conduct grab sampling every four hours until the continuous monitoring equipment is returned to service.

c. The water supplier for the public water system shall resume continuous residual disinfectant monitoring, as soon as possible, but no later than 14 days after the failure.

2. The water supplier for a community water systems serving 3,300 or fewer people shall be allowed to monitor the residual disinfectant concentration less than continuously, if the water supplier receives approval under s. NR 811.48(3) (b) to monitor less than continuously. The monitoring shall be done using analytical methods and requirements specified in s. NR 809.563 at a location approved by the department and the residual disinfection concentration shall be recorded from that water every day the groundwater source is served to the public.

a. The groundwater system shall maintain the department determined residual disinfectant concentration every day the groundwater system serves water from the groundwater source to the public. The water supplier for a groundwater system shall take a daily grab sample during the hour of peak flow or at another time specified by the department.

b. If any daily grab sample measurement falls below the department determined residual disinfectant concentration, the water supplier shall take follow-up samples at the frequency determined by the department under s. NR 811.48(3) (b) but no less than four hours until the residual disinfectant concentration is restored to the department determined level.

3. Water suppliers for non-community systems serving 3,300 or fewer people, unless otherwise required by the department under s. NR 812.37, shall monitor the residual disinfectant concentration using analytical methods and requirements specified in s. NR 809.563 at a location approved by the department and record the residual disinfection concentration once each day that water from the groundwater source is served to the public.

a. The water supplier for a groundwater system shall maintain the department determined residual disinfectant concentration every day the groundwater system serves water from the groundwater source to the public. The water supplier for a groundwater system shall take a daily grab sample during the hour of peak flow or at another time specified by the department.

b. If any daily grab sample measurement falls below the department determined residual disinfectant concentration, the water supplier shall take follow-up samples every four hours until the residual disinfectant concentration is restored to the department determined level.

c. Alternatively, water suppliers for non-community groundwater systems that serve 3,300 or fewer people may monitor continuously in order to meet the requirements of subd. 1.

(b) Membrane filtration. A water supplier for a groundwater system that uses membrane filtration to meet the requirements of sub. (2) shall monitor the membrane filtration process in accordance with all department specified monitoring requirements and shall operate the membrane filtration in accordance with all department specified compliance requirements. To be in compliance with the requirement to achieve at least 4-log treatment of viruses when a public water system uses membrane filtration exclusively, the public water system shall meet all of the following:

1. The membrane shall have an absolute molecular weight cut-off (MWCO), or an alternate parameter that describes the exclusion characteristics of the membrane, that can reliably achieve at least 4-log removal of viruses.

2. The membrane process shall be operated in accordance with department-specified compliance requirements.

3. The integrity of the membrane is intact.

4. The public water system shall be provided with at least 2 log of additional treatment of viruses using a chemical disinfectant.

(c) Alternative treatment. A water supplier for a groundwater system that uses a department-approved alternative treatment to meet the requirements of sub. (2) (d) for providing at least 4-log treatment of viruses before or at the first customer shall do all of the following:

1. Monitor the alternative treatment in accordance with all department specified monitoring requirements.

2. Operate the alternative treatment in accordance with all compliance requirements that the department determines to be necessary to achieve at least 4-log treatment of viruses.

(5) DISCONTINUING TREATMENT. A water supplier for a groundwater system may discontinue 4-log treatment of viruses before or at the first customer for a groundwater source if the department determines and documents in writing that 4-log treatment of viruses is no longer necessary for that water source. A public water system where 4-log treatment of viruses is discontinued is subject to the source water monitoring requirements of s. NR 809.325.

(6) FAILURE TO MEET MONITORING REQUIREMENTS. If a water supplier fails to meet any of the monitoring requirements of sub. (4), the public water system is in violation and the water supplier shall complete public notification requirements under s. NR 809.953.

Disclaimer: These regulations may not be the most recent version. Wisconsin may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.