Wisconsin

Wisconsin adopted state drinking water standards for PFAS in 2022 through the Department of Natural Resources under NR 809. The Wisconsin standard sets a combined limit of 70 parts per trillion for the sum of PFOA and PFOS. This combined threshold is less strict than the federal EPA individual MCLs of 4 parts per trillion for each compound finalized in April 2024, and Wisconsin utilities now must meet the stricter federal standards.

The impetus for Wisconsin's regulatory response came from the Marinette and Peshtigo area, where the Tyco Fire Products facility used and disposed of AFFF firefighting foam for training exercises starting in the 1960s. PFOA and PFOS were detected in extraction wells at levels exceeding 10,000 parts per trillion, and Tyco and parent company Johnson Controls signed a settlement funding an alternate water supply program that still includes bottled water deliveries to some households. Other contaminated sites include the Madison area around Truax Field and various paper mill legacy sites in the Fox Valley.

The Wisconsin legislature passed Act 101 of 2021, which established a framework for state PFAS regulation and included some enforcement tools. Governor Tony Evers and Republican legislative leaders have had ongoing disputes over expanding PFAS response funding, and the state has appropriated funding for impacted well owners in several budget cycles.

Litigation has been active. The Wisconsin Attorney General has sued 3M, DuPont, Tyco, and other manufacturers. State records show the DNR maintains a PFAS Action Council and publishes a public dashboard tracking contamination sites. Public water systems in Wisconsin are subject to both the state NR 809 standard and the federal compliance timeline requiring initial monitoring by 2027 and treatment installation by 2029.