If you operate a drinking water system, PFOA and PFOS are no longer just a monitoring obligation. They are now designated hazardous substances under CERCLA — the federal Superfund law — and that single classification changes your liability exposure. Check your water system's compliance status free at orevant.com before you read on, because the liability clock does not care whether you manufactured the chemical or merely received it in your source water.

What the designation actually does

On July 8, 2024, PFOA and PFOS became the first PFAS compounds listed as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA, or Superfund), codified at 40 CFR 302.4. The D.C. Circuit upheld that designation on appeal, and in September 2025 EPA announced it would retain the listing and begin work on a section 102(a) "Framework Rule" to govern future hazardous-substance designations.

See exactly what your system is up against

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The practical consequence is strict, retroactive, and joint-and-several liability. CERCLA does not ask who was negligent — it asks who released the substance into the environment. That can sweep in parties that never manufactured or generated a drop of PFAS.

Why a water system is in the blast radius

Water utilities are the textbook "passive receiver." You did not make PFOA. You did not dump it. You drew it out of the ground or the river, treated it as best you could, and delivered it to customers. Under a strict reading of CERCLA, the act of discharging treatment residuals, backwash, or spent filter media that contain PFAS can look like a "release" — and a municipality that disposed of PFAS-bearing waste can find itself named in a Superfund allocation.

That is exactly the scenario EPA itself flagged when it issued its PFAS Enforcement Discretion and Settlement Policy alongside the designation. EPA committed to not pursue "equitable" parties — community water systems, public airports, farms, and certain other passive receivers — where they did not cause the contamination. But that is an enforcement-discretion policy, not a statutory shield, and it does not protect you from third-party cost-recovery suits or from a state agency exercising its own authority.

The two-sided risk most operators miss

There are two ways this lands on your desk:

  1. You get named. A downstream party, a landfill neighbor, or another utility seeks to recover cleanup costs, and your treatment plant is in the chain of custody.
  2. You need to recover. Your source water is contaminated by an upstream industrial source, and the only mechanism that forces them to pay for your treatment or a new source is a CERCLA cost-recovery claim — which now exists because PFAS is a hazardous substance.

Both sides run through the same public record an inspector reviews, and both are easier to manage when you already know your own monitoring status and violation history. See what changed in PFAS rules and what still applies, and the PFAS monitoring deadlines you are already on the hook for.

What to do now

  1. Confirm whether PFOA/PFOS have ever been sampled in your source water — if not, your status is unknown, which is the most expensive status to be in during a liability dispute.
  2. Document your treatment residuals and waste disposal path, because that is where a "release" allegation will point.
  3. Pull your system's current compliance record so you can distinguish a monitoring gap (fixable now) from an actual exceedance (an obligation you must meet).

Most systems do not face Superfund liability next month. But the systems that get caught flat-footed are the ones that did not know their own record.

Check your water system's compliance status — free at orevant.com (no account required).

Sources: 40 CFR 302.4 (PFOA/PFOS CERCLA designation, effective July 8, 2024); EPA PFAS Enforcement Discretion and Settlement Policy (April 2024); D.C. Circuit ruling upholding the designation; EPA September 17, 2025 announcement retaining the designation and initiating a 102(a) Framework Rule.

FAQ

Is a water system automatically liable just because PFAS was in its source water?

No. Liability turns on a release into the environment, not on mere receipt of PFAS in source water. But water systems that disposed of PFAS-bearing treatment residuals or backwash can face a release theory, and EPA's enforcement-discretion policy is not a complete shield against third-party cost-recovery claims. This is a legal question; Orevant is compliance information tooling, not legal advice.

We have never sampled for PFAS. Are we exposed?

Unknown is the most expensive status. Without sampling data you cannot demonstrate that you are not a source, and you cannot show whether your treatment residuals contain PFAS. A $199 compliance scan maps your PFAS monitoring obligation and current record so you are not caught without a baseline.