Wisconsin's Marinette Hotspot

One of the Midwest's most serious PFAS hotspots sits in Marinette and Peshtigo, where Tyco Fire Products, a Johnson Controls business, manufactured and field-tested firefighting foam. That activity left behind some of the highest groundwater PFAS concentrations ever recorded in the country: PFOA at the Tyco site was measured as high as 254,000 ppt. In 2026 Wisconsin secured a $10 million settlement with Tyco and JCI to fund cleanup and deliver clean drinking water across Marinette County (sources: WPR, Wisconsin Examiner, WI DNR). This is a thoroughly documented, foam-driven case, not conjecture, and the scale of the numbers is what sets it apart from routine background detections.

Living in or near Marinette County is therefore a direct reason to confirm what your own water holds. Wisconsin has also broadened its PFAS sampling of both municipal supplies and private wells over recent years, which means a growing number of communities now work from measured data instead of guesswork. Across the rest of the state, detection varies from one system to the next and one well to the next, so a personal test is what actually reveals where you stand.

The magnitude at Marinette is easy to underappreciate until it is set against the yardstick. A groundwater reading of 254,000 ppt sits tens of thousands of times above the 4 ppt federal limit for PFOA, which is why the case drew a formal settlement and a mandate to supply clean water rather than a routine notice. Because Tyco both made and tested foam on that ground, the contamination is concentrated and traceable to a specific operation, the kind of clear causal chain that is often missing in diffuse cases. For nearby residents the settlement funds matter, but so does personal confirmation, since plume edges shift and a neighbor's clean well is not proof about yours.

Wisconsin's 70 ppt Standard and the 2024 Federal Limits

Wisconsin adopted a combined PFOS-and-PFOA drinking-water standard of 70 ppt, as documented by BCLP. In 2024 the EPA finalized markedly stricter enforceable national limits: 4 parts per trillion each for PFOA and PFOS and 10 ppt each for PFNA, PFHxS, and GenX (HFPO-DA). Because those federal MCLs are far tighter than the earlier state figure, Wisconsin's public systems are now held to the federal thresholds.

How to Test Your Water

Wisconsin utilities fold PFAS monitoring into their annual water-quality reports, which is the first place a city customer should look. Private-well owners, extremely common across the state's rural counties, receive no utility report and should rely on a lab certified for EPA Method 537.1 or 533. PFAS is colorless, tasteless, and odorless, so testing is the only reliable way to learn your levels.

Three Proven Removal Methods

Granular activated carbon (GAC) adsorbs longer-chain compounds such as PFOA and PFOS and is a common whole-house choice. Strong-base anion-exchange resin captures a broader range, including shorter-chain compounds that can slip past carbon. Reverse osmosis (RO) drives water through a membrane and rejects the widest array of PFAS at a single tap.

Point-of-entry systems treat every fixture, showers, laundry, and kitchen alike, while point-of-use units concentrate on drinking and cooking water. Many Wisconsin households, especially within the affected areas, run a whole-house carbon or anion system alongside an RO unit at the kitchen sink. Because these media gradually reach capacity, plan for periodic media or cartridge changes and a follow-up test so you can confirm the system is still holding PFAS beneath the federal limits.

With Marinette's documented contamination on record, test your water and match a proven method to your result.