Earlier today, Gov. Tony Evers announced his approval of Wisconsin's first groundwater standards for six per- and polyfluoroalkyl substances (PFAS). The rule sets enforcement standards of 4 parts per trillion (ppt) for PFOA and PFOS; 10 ppt for PFNA, PFHxS and GenX (HFPO-DA); and 2,000 ppt for PFBS, along with a preventive action limit equal to 10% of the applicable enforcement standard. The groundwater standards are separate from the PFAS drinking water standards Wisconsin adopted earlier in 2026.
The standards have significant implications for industrial facilities, wastewater treatment plants, landfills and other permitted water discharges, as well as potentially impacting open remediation cases. The standards will likely require more sampling for permitted discharges, and may lead to additional investigation, remediation and waste-management obligations where PFAS contamination exceeds applicable preventive action limit. They may also require changes to the handling and disposal of PFAS-containing sludge and biosolids. The Wisconsin Department of Natural Resources' (DNR) rulemaking analysis anticipated compliance costs below the $10 million over any two-year period threshold that would trigger additional legislative review under Wisconsin's REINS Act, although industry and wastewater representatives disputed whether the analysis fully captured likely costs.
The practical impact will depend on how the DNR implements and enforces the standards, including how they apply to existing permit holders and existing remediation cases. The approval represents a major change in Wisconsin's groundwater regulatory framework, but the extent of the resulting obligations and costs will depend on site-specific conditions and applicable legal requirements.
If you have questions regarding this alert, please contact Delanie Breuer or Jessica Biggott.
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