Court Keeps PFAS Limits in Place as Legal Fight Unfolds

On January 21st the legal battle over America’s new limits on “forever chemicals” took a procedural turn. The U.S. Court of Appeals for the D.C. Circuit refused the Environmental Protection Agency’s request to swiftly scrap parts of its own rule. For now, the standards remain in place.

The rule in question, finalised in April 2024, set binding limits in drinking water for six per- and polyfluoroalkyl substances (PFAS): PFOA, PFOS, PFHxS, PFNA, HFPO-DA and PFBS. After litigation began, the EPA asked the court to vacate limits for four of them without full briefing, signalling that it might revise or reconsider those thresholds. The court declined to do so summarily and instead set a schedule for full arguments on the merits.

The January order settles little beyond timing. It preserves the status quo while judges review the case. It does not endorse the substance of the regulation. Nor does it prevent the EPA from pursuing revisions through the normal rulemaking process. Law and policy are advancing on parallel tracks.

For public water systems, that distinction matters less than the immediate effect. The 2024 standards remain legally operative. Utilities must continue monitoring, reporting and planning for compliance under existing deadlines. Any future changes would require formal rulemaking and could alter obligations or timelines. None have yet taken effect.

This uncertainty shapes behaviour. Since 2024 many utilities have begun PFAS testing and preliminary treatment planning. Laboratories and technology providers remain busy with monitoring and pilot projects. Yet capital investments are being weighed against the risk that some limits could shift.

Smaller systems face the sharpest dilemma. Compliance may demand heavy spending, even as parts of the rule are under judicial review and possible administrative reconsideration. Federal and state funding schemes therefore play an outsized role in easing costs.

Manufacturers and industrial facilities confront a similar reality. Federal limits apply today, even if their long-term contours remain contested.

The message from the court is restrained but clear. America’s PFAS standards stand, for now. The litigation continues. So does regulatory change.