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Water Quality PFAS Initiatives

The DNR is conducting a number of initiatives related to per- and polyfluoroalkyl substances (PFAS) contamination and water quality in Wisconsin. These initiatives are:

  1. municipal wastewater treatment plant screening;
  2. surface water and fish tissue sampling; and
  3. adoption of new surface water quality criteria.

More information about each of these initiatives is available on this page, and additional information and data will be posted as it becomes available.

1. Municipal wastewater treatment plant screening

In July 2019, the DNR requested that 125 municipal wastewater treatment facilities sample their influent and effluent for PFAS compounds to gain a better understanding of how and where PFAS contaminants could be entering the air, land and waters of the state. Municipal wastewater treatment facilities with potential PFAS sources discharging to their sanitary sewers received the letter.

Wastewater treatment plants are not a source of PFAS, but many industries that have historically used PFAS may be discharging these compounds into sanitary sewers. Therefore, Publicly Owned Treatment Works (POTWs) are a logical screening point for identifying potential significant sources of PFAS across the state. Getting data regarding sources will help the DNR:

  • scope the extent and locations of PFAS contamination in effluent throughout the state;
  • prioritize efforts to address PFAS impacts as necessary to protect human health and the environment with currently available regulatory tools; and
  • accurately project economic impacts of adoption of water quality and groundwater standards during rulemaking.

In addition, this data will help wastewater permittees deal with PFAS sources now, instead of waiting until a surface water quality standard is developed. POTWs with sampling results above the screening levels can proactively work to identify sources within their collection system and develop pretreatment or source reduction strategies to reduce or eliminate the PFAS discharge.

How facilities were selected

Municipal wastewater treatment plants were asked to sample their influent and effluent based on several selection criteria.

  • The 27 largest municipalities were selected as these facilities are authorized to permit industrial discharges to their own sanitary sewers and have the most industrial contributors in terms of flow.
  • An additional 91 municipalities receiving wastewater from Significant Industrial Users (SIUs) - which are industrial users subject to categorical pretreatment standards, the majority of which are metal platers and finishers.
  • The remaining municipalities were added based on search results of the facility factsheet that included potential PFAS sources. The intention of this search was to identify municipalities with likely PFAS sources that are not SIUs.

2. Surface water and fish tissue sampling

Information about the statewide monitoring project to sample fish tissue and water chemistry at select sites is now available at: Surface Water and Fish Tissue Sampling.

3. Adoption of new surface water quality criteria

In Wisconsin, PFAS have been detected in drinking and surface water near sources of industrial use or manufacture and near spill locations. Thus, the DNR is working to create human health surface water quality criteria for perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), as well as any other PFAS which the department determines may be harmful to human health in ch. NR 105, Wis. Adm. Code.

Water quality standards protect public health and welfare, recreational uses and the propagation of fish and other aquatic life. The standards consist of numeric or narrative criteria and designated uses. Water quality criteria specify the level of a pollutant that is protective of a designated use.

Adoption of new surface water quality criteria for a toxic pollutant can result in the imposition of new water quality-based effluent limitations (WQBELs) and additional monitoring requirements in WPDES permits issued to municipal and industrial facilities that discharge the pollutant. The proposed criteria are expected to be numeric and may be expressed as a single number applicable to all waters of the state, or may be expressed as different numbers that are applied to different surface water body types.

The department will follow the administrative rulemaking process and the public will have multiple opportunities to participate in the rulemaking effort. This process generally takes about 31 months from initiation to promulgation.