This article was updated at 8:35 a.m., March 18, 2026.

March 18, 2026 – Wisconsin may have new drinking water regulations limiting permissible amounts of PFAS after approval by the Natural Resources Board (NRB) Jan. 28 and the governor’s signature March 2 – unless the Wisconsin Legislature still has power to stop it.

The amendments to Wisconsin Administrative Code chapter NR 809signed by Gov. Tony Evers could need review by the legislature prior to promulgation, depending on how partisans interpret a 2025 Wisconsin Supreme Court decision.

Reasons exist to question the stricter rules for safe water.

Although Wisconsin adopted the rules out of necessary compliance with the U.S. Environmental Protection Agency (EPA) regulations, for reasons political and scientific the EPA has been backing away from its rules.

If the EPA’s rule fails judicial review, Wisconsin could have more stringent regulations than the EPA – with the clock ticking fast for compliance by water utilities.

“The compliance deadlines under the Safe Drinking Water Act (SDWA) don’t seem like they’re right on top of us,” said Edward “Ned” Witte, a Wisconsin environmental attorney with Earth & Water Law, a firm based in Washington, D.C.

“But when it comes to actually planning, capital spending, construction, and achieving compliance, there’s a lot of work to be done in a relatively short period of time.”

‘Miracle Substance’

PFAS began in the 1940s as a solution. This type of chemical – and there are thousands – “was kind of a miracle substance because it was so effectively water-resistant, oil-resistant, and so durable,” Witte said.

Consumers may recognize its applications in products such as Scotchgard and Teflon.

Less familiar, it’s what makes aqueous film forming foam (AFFF), a firefighting foam used at airports.

PFAS doesn’t break down – hence the term “forever chemicals” – and began appearing in the environment.

Exposure to PFAS has been linked to low birth weight, reduced immunity, cholesterol and hormone levels, liver and kidney damage, and cancer, according to DNR’s Fiscal Estimate & Economic Impact Analysis for the new rules.

The problem of PFAS got overlooked. Under the Toxic Substances Control Act (TSCA), a manufacturer must report to the EPA any new chemical, “and that never happened,” Witte said.

Concern has grown during the last 20 years.

“I think that the regulatory agencies are hurrying to catch up, and a lot of rulemaking happened during the four years of the [President Joe] Biden administration,” Witte said.

Wisconsin’s Attempts

The Wisconsin Department of Natural Resources (DNR) response follows that trajectory, marked by legal challenges.

The DNR published an interim decision on its website in 2019 that offered only limited liability for voluntary reporting of emerging contaminants, “specifically PFAS.”

In a subsequent letter to responsible parties and on its website, the DNR defined PFAS as a hazardous substance under the Spills Law at Wis. Stat. section 292.01(5).

A lawsuit challenged the DNR’s actions as illegal unpromulgated rules.

In Wisconsin Manufacturers and Commerce, Inc. v. DNR, 2025 WI 26, the Wisconsin Supreme Court ended the dispute in a 5-2 decision, holding that the DNR’s communications were legitimate guidance documents.

In another conflict, Evers has fought with the Legislature to release $125 million in the 2023-25 biennial budget for PFAS cleanup.

The standoff resulted in Evers vetoing2023 Senate Bill 312, which would have created PFAS clean-up grant programs and limitations that he believed hamstrung the DNR.

The DNR attempted to pass PFAS regulations in 2022, but the NRB didn’t agree with all of them.

The NRB voted down groundwater quality standards, approved surface water quality criteria, and modified proposed drinking water standards, raising the maximum contaminant level in the proposed regulations from 20 to 70 parts per trillion (ppt).^[1]

The EPA had no PFAS rule, only “an informally promulgated number of 70 ppt, … but it really wasn’t scientifically defensible,” Witte explained.

Out of the regulations approved in 2022, Wisconsin began monitoring PFAS levels.^[2]

Wisconsin’s Rule – and Deadline

The EPA promulgated its PFAS SDWA rule, 40 CFR Part 141, Subpart Z, in 2024. That set the clock running for the DNR.

Wisconsin has primary enforcement, called “primacy,” and may run its own drinking water program as long as the DNR keeps up with the EPA – and that means enacting state regulations “no less stringent” than the EPA’s within two years.^[3]

If Wisconsin fails, the EPA can come in and enforce the SDWA.

With that deadline, the DNR sought approval of its PFAS rule, so consistent with the EPA’s that the language ignores Wisconsin administrative rule stylistic conventions.

A lot of pages create a few fundamental requirements. Wisconsin sets PFAS and PFOA maximum contaminant levels to 4 ppt, sets levels at 10 ppt for three other PFAS substances, and adopts a hazard index.

The hazard index represents the synergistic effects of multiple PFAS chemicals even below individual maximum contaminant levels.

PFAS monitoring under Wisconsin’s rule must be completed by April 26, 2027, and water system compliance two years after that.

Administratively Orphaned

One of the criticisms raised in the DNR rulemaking process noted that the EPA has indicated its desire to limit application of the federal rule and encouraged states to ask for extensions.

After the EPA promulgated its rule, various groups sued the EPA in the U.S. Court of Appeals for the District of Columbia Circuit.

The “EPA did not rely on the best available science and the most recent occurrence data, and used novel approaches as the basis for certain parts of the rule” and “significantly underestimated the costs of this rule,” plaintiffs claimed.

The EPA’s promulgation failed to follow the steps required by the SDWA, doubling up on some of those steps, eliminating required opportunities for public comment, plaintiffs said.

The hazard index itself, they argued, was novel, arbitrary, and capricious.

Under the Biden Administration, the EPA defended itself, but under President Donald Trump, the EPA asked the court for time to reconsider its position.

Last fall, the EPA sought a partial vacatur of the rule, defending its PFAS and PFOA rules but abandoning the other three substances and the hazard index.

The District of Columbia Circuit panel said the EPA’s decision had merit, Witte said.

Nationwide analysis of drinking water systems showed that the PFAS and PFOA maximum concentration level of 4 ppt “would make sense to regulate and to put in place controls for those substances.”

“But as to the other three, plus the hazard index, the detections were far lower,” sometimes nonexistent, Witte said.

“We kind of got this a little bit backwards,” Witte summarized, “because there was such a rush to regulate PFAS that some of these standards were put in place and then this testing happened.”

“There’s some justification for why the U.S. EPA is seeking to rescind the standards that have been proposed and now are legal.”

Although both plaintiff and defendants agreed, the court didn’t.

“The merits of the parties’ positions are not so clear as to warrant summary action,” the court said in its Jan. 21 order rejecting partial vacatur.

The rule litigation creates uncertainty. If the court strikes down parts of the rule, Wisconsin could be left with regulations stronger than federal ones.

“There’s a potential issue with anti-backsliding, that once you have a regulation, it can’t become less stringent,” said Jared Walker Smith at Boardman & Clark LLP in Madison, whose municipal law practice emphasizes public water utilities.

If Wisconsin promulgates the new PFAS rule, “then regardless of what the federal EPA does, it is likely that these standards would remain Wisconsin standards going forward, even if they are more stringent than any federal requirement.”

It can also mean that any delay that the EPA allows in enforcement may not apply to Wisconsin.

‘A Big Rush’

“The vast majority of public water utilities in Wisconsin already meet the standards that have been proposed for adoption by the DNR,” Smith said.

Wisconsin has 1,025 community water systems run by municipalities and businesses for apartment buildings, mobile home parks, and condominiums, according to the DNR’s Economic Impact Analysis.

Another 893 non-transient non-community water systems are smaller, business operations.

The DNR rule analysis included the EPA’s estimated annualized compliance costs for community water systems of $24.7 million, and for the non-transient non-community water systems at about $1.9 million.

Wisconsin has 96 public water systems that have submitted to DNR at least one sample that exceeds the PFAS rule standards, the rule analysis states.

“We still have a fair amount of data from our public water utilities about whether they have PFAS in their water and, if so, at what levels, and that’s not the case in a lot of states,” Smith said.

Early testing has alerted water utilities of potential problems, Smith said. Some utilities have already responded by shutting down problematic wells or installing treatment systems.

A lot of water systems are small, and they will be looking for funding sources from grants, loans, or rate increases that raise water bills, Smith said.

The ubiquitous water utilities, often overlooked, face many pressures. Some are working to remove old lead service lines. Planned changes to NR 809 would tighten lead and copper compliance, Smith said.

The infrastructure work itself has become more challenging, Smith said, “with the decreasing number of contractors who perform and do these types of construction projects, and higher supply chain costs.”

The head start Wisconsin has may not be enough, Witte said. “I don’t think that public water systems will have enough time.”

“It’s going to be a rush. It’s going to be a big rush.”

Nearing Resolution?

The PFAS rule comes when related issues may be nearing resolution.

The dispute between Evers and the legislature about PFAS cleanup funding recently has seen “some potentially positive movement,” Smith said.

A PFAS liability and grant program proposal, 2025 Assembly Bill 131, passed the Senate on Tuesday, March 17, 2026, after the Assembly approved it 93-0.

As those promising signs remain in suspension, so is the drinking water PFAS rule, which faces the uncertainty of how much power, if any, the legislature has in reviewing administrative rules.

In Evers v. Marklein, 2025 WI 36, the Supreme Court held unconstitutional five statutes that granted the Joint Committee for Review of Administrative Rules (JCRAR) “power to pause, object to, or suspend administrative rules for varying lengths of time.”

Based on that decision, Evers announced in an Aug. 12 letter that agencies may submit rules to the Legislative Reference Bureau for publication without legislative committee review.

Legislative review statutes remain in Wis. Stat. sections 227.19 and 227.26, although the Legislative Council advises “uncertainty remains regarding whether other elements in the rulemaking process are legislative actions that also constitute impermissible ‘pauses’ in the rulemaking process.”

“I don’t know how that’s going to be resolved or its impact on these particular rules, as I’ve not seen anything that’s necessarily addressed that idea,” Smith said.

Endnotes

[1] Vanessa D. Wishart, An Update on PFAS Regulation in Wisconsin, Envtl. Law Blog, Apr. 27, 2022, https://www.wisbar.org/NewsPublications/InsideTrack/Pages/Article.aspx?Volume=14&ArticleID=29063 (last visited Mar. 12, 2026).

[2] NR 809.205(1g)-(1r), Wis. Admin. Code.

[3] 42 U.S.C. section 300g-2(a)(1); 40 C.F.R section 142.2 (defining “primary enforcement responsibility”); 40 C.F.R. section 142.10 (establishing primacy requirements), 40 C.F.R. section 142.12 (setting standards for state revision to maintain primacy); Wis. Stat. section 281.17(8)(a) (permitting DNR to “establish, administer and maintain a safe drinking water program no less stringent than” the SDWA).