EPA’s Effort to Pull Back PFAS Limits Spurs Statutory Tug of War

The EPA is attempting an end run around the Safe Drinking Water Act by trying to rollback drinking water limits it previously set for four PFAS, attorneys representing affected communities said in legal briefs.

But the Environmental Protection Agency’s rollback would correct portions of a drinking water rule crafted through an unlawful procedure and based on erroneous data, water utilities’ and chemical manufacturers’ attorneys countered in separate response briefs filed Friday in an ongoing challenge to the Biden-era rulemaking.

At issue is the Trump administration’s request earlier this month asking the US Court of Appeals for the District of Columbia Circuit to vacate drinking water limits set last year for four specific per- and polyfluoroalkyl substances (PFAS).

Three groups of plaintiffs—water systems, chemical manufacturers, and communities that have dealt with contaminated drinking water—responded on to the EPA’s vacatur motion by prioritizing different parts of the Safe Drinking Water Act’s (SDWA) requirements.

They asked the D.C. Circuit to decide whether a procedural error the EPA now says it made when it regulated the four PFAS outweighs the statute’s goal of protecting public health concerns.

Scrapping the limits the agency set for the four PFAS “would risk significant public health harm,” said the response from Earthjustice and the Natural Resources Defense Council, who represent affected communities. Their brief pointed out the Biden-era EPA estimated 18 million people drink water with high enough levels of the chemicals to damage reproduction, the immune system, and multiple organs.

But other data showed the four PFAS are almost always at levels below what the agency thought harmful, the chemical manufacturers said in their response.

Utilities were unable to provide the EPA with views on that information, because the agency skipped a public comment period in the rulemaking process—a step mandated by the SDWA, said water systems and chemical manufacturers in their separate responses.

“The agency’s legal error constitutes the type of serious deficiency that typically warrants vacatur,” the water associations said in their response to the EPA’s request.

Had EPA followed the act’s mandatory procedure, and obtained additional public input, it may not have finalized provisions of the rule it now seeks to vacate, the chemical manufacturers said.

‘Anti-backsliding Provision’

Any procedural error the EPA may have made can’t justify canceling the EPA’s standards, said the community groups’ response.

The agency’s attempted vacatur “would accomplish an end run around Congress’s purposeful prohibitions against agency flip-flopping on protections for the nation’s drinking water,” their response said.

“First, the act ‘does not permit EPA to withdraw a regulatory determination’ after it is finalized,” they said.

Second, the act’s ‘anti-backsliding’ provision requires that ‘each revision [of a standard] shall maintain, or provide for greater, protection of the health of persons,’” the community groups’ response said.

The D.C. Circuit should convene a merits panel, a group of judges to decide whether the EPA’s vacatur motion can be considered by the court, the community groups said.

The SDWA’s anti-backsliding provision doesn’t prevent the EPA from revisiting an unlawful rule, the chemical manufacturers’ response said.

“It is one thing for Congress to restrain an agency’s power to revise rules just because it has reevaluated the facts; it would be something else entirely for Congress to bind the agency to a rule that was invalid in the first place,” the chemical manufacturers’ response said.

The case is American Water Works Ass’n v. EPA, D.C. Cir., No. 24-01188, Response Motions Filed, 9/26/25.