Clean water groups hail new PFAS limits for drinking water

For about a decade, clean-water advocates have sounded an alarm about PFAS, or “forever chemicals,” in drinking water, fish and wildlife in Wisconsin.

Johnson Controls’ acknowledgement in 2017 of per- and polyfluoroalkyl substances, or PFAS, detected in groundwater near its Tyco fire suppression operations in Marinette and the Town of Peshtigo ignited concern among residents and environmentalists in the greater Northeast Wisconsin concerned about drinking water, likely due to the facilities’ proximity to the bay of Green Bay.

Since then, grassroots groups like Clean Water Action Council in Green Bay have pressed elected officials to address the issue of clean water through more stringent PFAS limits in drinking water.

On Jan. 28, the Wisconsin Natural Resources Board heeded their calls when it approved new, lower limits of 4 parts per trillion for PFOS and PFOA, two common varieties of PFAS, matching the U.S. Environmental Protection Agency’s maximum contaminant levels (MCLs).
Limits for other varieties were lowered to 10 ppt for PFHxS, HFPO-DA and PFNA, while a Hazard Index was set at 1 for mixtures of two or more PFAS, including PFBS.

Adopting EPA’s maximum contaminant levels might tame the flow of PFAS from industrial use, but Clean Water Action Council Board President Dean Hoegger said Congress should take on the chemical industry producing new PFAS variants that aren’t subject to the regulations.

“Congress also needs to pass legislation that requires more of the chemical industry to prove these new chemicals are safe for human health and the environment: A prove-it first law,” Hoegger said.

While most Brown County communities already provide drinking water conforming to the new, lower PFAS limits, Hoegger acknowledged the battle for groundwater standards continues, especially in Marinette and the Town of Peshtigo, where PFAS thought to stem from Johnson Controls’ Tyco manufacturing plan have contaminated the groundwater.

Tyco has constructed new deep wells for some residents affected by the contamination, while others have relied on the Wisconsin Department of Natural Resources to foot the bill for bottled water, as DNR has said their well water could contribute to health issues.

While awareness has grown, the issue hasn’t gone away. “We know that PFAS is in Lake Michigan,” said Andrea Hay, director of communications for Green Bay Water, the city’s drinking water utility.

“When this first came out, and especially with everything that happened with Tyco in Marinette County, interested skyrocketed,” Hay said.

In 2018, when the question arose of whether the City of Green Bay should test for PFAS in the water, Hay was among those who said, “Yes, let’s test for it. We should know what’s in our water,” she recalled. It has sampled for PFAS since then and uses the EPA MCLs as its criteria, she said.

The city pulls its water from a mile off the shore of Kewaunee in Lake Michigan water about 60 feet deep, Hay said. “It’s some of the cleanest water,” she said.

Its 2024 water quality report suggests PFOS was detected between 1.4 and 2.0 ppt, while PFOA was detected between 1.5 and 2.2, with the highest measurement just above the new criteria, according to data on the city’s website. Wisconsin’s recommended Health Advisory Limit at the time was 20 ppt for the two variants, according to the water quality report.

“We manage this through routine monitoring and comparing it to the health based standard. If the level were to approach or exceed the regulatory limit, technologies would need to be implemented,” Hay said.

While wastewater isn’t expected to meet the same criteria as drinking water, testing for PFAS in wastewater also indicates how widespread forever chemicals are.

Samples taken at NEW Water’s Green Bay and De Pere wastewater treatment facilities indicate PFOA and PFOS were present in 2023 and 2024.

Surprisingly, in some cases the detected levels increased after treatment. For example, the data suggest the treated average of PFOA was 16 ppt at the Green Bay Facility in 2024, compared with an untreated average of less than 14 ppt.

Asked why the levels might increase after treatment, NEW Water spokesperson Tricia Garrison said, “This is something that NEW Water is currently evaluating. As scientific knowledge evolves on PFAS, NEW Water continues to partner with industry organizations and leaders to better understand the issue.”

PFAS stems from many sources, including soap and wax manufacturing for car washes, paper mills, metal finishing plants and commercial and residential wastewater, according to NEW Water’s data from collection systems.

NEW Water’s sampling detected PFOA at landfills at concentrations of up to 1,200 ppt, while the amount of PFOS detected at sewershed basins ranged from 2.5 ppt to 220 ppt.
While Johnson Controls Inc.’s Tyco fire suppression operations in Marinette often are blamed for PFAS detected in groundwater in northeast Wisconsin, many other sources exist, a Tyco spokesperson said.

“PFAS contamination is a widespread issue across Wisconsin and the country, with many historical and ongoing sources,” the spokesperson said.

PFAS detected in Green Bay-area ducks last fall prompted the Department of Natural Resources to issue a health advisory warning hunters not to eat the waterfowl, putting forever chemicals back on the hotseat in Brown County.

PFOS-based advisories also are in effect for anglers who might catch rock bass and smelt in the bay and tributaries flowing into it in northeast Wisconsin and yellow perch and smelt in Lake Michigan, the DNR said. The DNR warns not to eat much of those fish.

“As more PFAS chemicals enter Lake Michigan, the source of Green Bay’s water supply, PFAS levels will need watchful monitoring,” Hoegger said, to ensure the drinking water is safe to consume.

Just four years earlier, the Natural Resources Board had approved significantly higher limits of 70 parts per trillion.

Then came the Spill Law case of Wisconsin Manufacturers Commerce Inc. and Leather Rich v Department of Natural Resources.

In 2025, the Wisconsin Supreme Court heard the case and upheld the Spill Law, saying the DNR didn’t abuse its authority as an executive-branch agency when it acted “to protect public health and safety” and serve as “good stewards of state taxpayer dollars,” by demanding Leather Rich clean up a PFAS spill on its property, according to the opinion written by Justice Janet Protasiewicz. The opinion was based largely on the presumed dangers of PFAS, or per- and polyfluoroalkyl substances.

Now, the Natural Resources Board, which governs the DNR, has lowered the amount of PFAS it considers too much in drinking water.

Throughout the state, about 100 Wisconsin public water systems, including some operated at small businesses, could exceed the new limits, a Department of Natural Resources spokesperson said.

According to the new rule, public water systems would have until 2029 to comply with the new Maximum Contaminant Levels. For those systems out of compliance in 2029, DNR would work with them on a corrective action, such as drilling a new well, improving the treatment process or connecting to an existing safe water source, DNR said.

The Natural Resources Board’s decision to approve the U.S. EPA standards is expected to increase testing of community drinking water systems for PFAS.