Wisconsin Sets New Groundwater Standards for PFAS
The state mandates a 4 parts per trillion limit on common chemical contaminants to protect drinking water supplies.
Updated on Oct. 30, 2026 in Environmental
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Governor Tony Evers has approved new, enforceable groundwater standards for six PFAS compounds in Wisconsin, setting a limit of 4 parts per trillion for PFOA and PFOS. These regulatory changes come after the state's Department of Natural Resources initiated a new rulemaking process earlier this year.
Why it matters
With 70% of Wisconsin residents and 95% of communities relying on groundwater for drinking, these enforceable limits are designed to mitigate health risks associated with PFAS exposure. The state is leveraging a $125 million trust fund to support the necessary infrastructure adjustments.
The new rules establish a strict 4 parts per trillion threshold for PFOA and PFOS contaminants. This limit applies to six total PFAS compounds, which are often used in fire-suppressant foams, to protect the state's significant groundwater supply.
The players
Tony Evers
The Governor of Wisconsin who approved the state's new regulatory standards for groundwater contaminants.
Department of Natural Resources
The Wisconsin state agency responsible for overseeing environmental protection and the rulemaking process for water quality.
Tyco Fire Products LP
A fire-suppressant manufacturer that reached a settlement for contamination at its Marinette Fire Technology Center.
Joint Committee on Finance
A legislative body that manages the release of state settlement funds to support water system testing.
The details
The Department of Natural Resources finalized these standards following health department recommendations that identified the risks of human-made PFAS—per- and polyfluoroalkyl substances, which are synthetic chemicals that persist in the environment and human bodies. The process involves testing public and private water sources to ensure compliance with the new parts-per-trillion caps. To support this testing, the Joint Committee on Finance has released $10 million from a legal settlement with Tyco Fire Products, which originated from contamination at the Marinette Fire Technology Center.
Timeline
2023-25: Wisconsin established the $125 million PFAS Trust Fund.
February 2025: DNR withdrew a previous proposal and initiated the new rulemaking process.
June 2026: Tyco Fire Products LP reached a legal settlement regarding its Marinette site.
October 2026: Governor Tony Evers officially approved the new groundwater standards.
The Tech Race
This policy follows the establishment of the state's $125 million PFAS Trust Fund, which provides the fiscal infrastructure for testing and remediation. The move marks a shift from funding support to binding environmental requirements for water safety.
Residents and communities will see these standards implemented through increased water system testing and potential treatment upgrades funded by the released settlement dollars. Homeowners and public utilities will be the primary participants in the upcoming testing cycle.
The takeaway
The implementation of these 4 parts per trillion limits signals a more aggressive state-level approach to long-term groundwater safety. Readers should monitor the DNR's upcoming grant program announcements for local testing opportunities and remediation timelines.
What happens next
The state expects to launch further grant programs in the coming months to support local water system treatment and well testing.
Further reading
Learn more about local testing efforts in our Environmental section.
Source note: This article includes information reported by Smart Water Magazine.
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Should your state government enforce strict groundwater contamination limits regardless of the regulatory costs?
