PFAS Contamination and Private Well Water in Marinette County, Wisconsin

What happened: decades of PFAS-containing firefighting foam at one site

From 1962 until 2017, Tyco Fire Products and its predecessor, the Ansul Company, used and tested firefighting foam containing PFAS (per- and polyfluoroalkyl substances, sometimes called "forever chemicals" for how slowly they break down in the environment) at a 380-acre Fire Technology Center located near the City of Marinette. Over more than five decades, foam discharged during fire-suppression testing soaked into the site's soil and worked its way into groundwater, eventually forming a documented contamination plume that extends beyond the facility itself and into the neighboring Town of Peshtigo.

The scale of contamination at the source site is severe by any standard: sampling has shown PFOA (one of the most heavily studied PFAS compounds) at levels as high as 254,000 parts per trillion in on-site groundwater, against a state and federal health-advisory framework generally measured in the tens of parts per trillion. As testing expanded outward from the site, contamination showed up well beyond the facility's boundary -- as of the most recent reporting reviewed for this page, 236 of 776 wells tested by Tyco or the Wisconsin DNR exceeded state groundwater health-advisory levels for PFAS, with some Town of Peshtigo wells testing above the state's drinking-water standard of 70 parts per trillion.

The state's case and the June 2026 settlement

In 2022, the State of Wisconsin filed suit against Tyco Fire Products and its parent company, Johnson Controls, alleging the companies had known about the contamination since at least 2013 (when it was first discovered through sampling) but did not notify the state for another four years. In June 2026, the state reached a $10 million settlement with the companies: Tyco must pay into a state PFAS cleanup trust fund and continue providing clean water -- bottled water, point-of-entry treatment systems, or new deep wells -- to affected residents for up to 20 years going forward. Governor Tony Evers described the settlement as a milestone in the state's broader PFAS cleanup effort, though it resolves the state's specific enforcement case rather than eliminating the underlying contamination itself.

An on-site groundwater extraction and treatment system has been operating since 2022, pulling contaminated groundwater from a series of wells, treating it to remove PFAS, and discharging the treated water into a nearby ditch -- more than 450 million gallons treated as of recent reporting. This has measurably reduced the volume of PFAS being discharged from the site, but has not eliminated PFAS from the surrounding groundwater, and the DNR has continued to expand its own well-testing and drinking-water-advisory program in the Town of Peshtigo as newer, stricter PFAS groundwater standards take effect -- meaning wells that tested clean under an older standard can later be reclassified as exceeding a newer one.

What this means geographically

The documented contamination is centered specifically on the area in and around the City of Marinette (site of the Fire Technology Center) and extending north into the Town of Peshtigo, where the plume has affected private wells. This is a localized, source-traceable contamination event tied to one facility's discharge history -- meaningfully different in both cause and geographic pattern from the county's shallow-karst or agricultural-nitrate well-contamination stories documented elsewhere in this project (Door, Kewaunee, Brown, Calumet, and other northeastern Wisconsin counties). That distinction matters practically: a well well outside the documented plume area may carry a very different risk profile than one inside or near it, so location relative to the known plume -- not just "Marinette County" as a whole -- is the relevant question.

What to actually do before buying near the City of Marinette or Town of Peshtigo

1. Check the Wisconsin DNR's dedicated PFAS Contamination in the Marinette and Peshtigo Area page (dnr.wisconsin.gov/topic/PFAS/Marinette.html) for the current, most up-to-date plume-area map and well-testing results before assuming a specific parcel is or isn't affected.
2. If a property has an existing well anywhere in or near the City of Marinette or the Town of Peshtigo, test specifically for PFAS (not just standard bacteria/nitrate) -- ask the DNR or a private lab whether the well has already been tested under the Tyco/DNR sampling program, and if so, request those results directly.
3. If the well has tested above state PFAS advisory or health-standard levels, ask what remediation the property is currently receiving (bottled water, a point-of-entry treatment system, or a new deep well through Tyco/JCI) and whether that arrangement transfers to a new owner or needs to be re-established.
4. Don't rely on an old test result or a neighbor's clean well as a substitute for testing the specific well on a specific parcel -- PFAS plume boundaries and concentrations can vary meaningfully over relatively short distances, and DNR testing and advisory levels have both expanded over time as standards tightened.
5. For a parcel outside the documented plume area but still in Marinette County, standard Wisconsin well-water due diligence still applies (see our national well-water guide) -- this page's contamination story is specific to the Marinette/Peshtigo area, not a countywide condition.