Per- and polyfluoroalkyl substances, known as PFAS, have become one of the most widespread and persistent contaminants in American drinking water. These man‑made chemicals resist heat, water, and oil, which made them ideal for nonstick cookware, waterproof clothing, firefighting foam, and industrial processes. But that same stability means they do not break down in the environment. They accumulate in groundwater and in human blood. When a private well is contaminated with PFAS, the well owner faces a health threat and a financial burden. The legal question is straightforward: who pays for the testing, treatment, and medical monitoring? This is not a matter of government regulation alone—it is a matter of tort law, where a private party can be held responsible for polluting someone else’s water.
The first step in any liability case is identifying the source. PFAS contamination of private wells typically comes from a few places. Military bases often used aqueous film‑forming foam for fire training, and that foam contained PFAS. Airports and chemical plants used similar products. Landfills that accepted PFAS‑laden waste can leak into surrounding groundwater. Even small manufacturing operations that used Teflon‑like coatings may have discharged PFAS into the soil. In many cases the contamination is invisible to the naked eye: the water looks and tastes normal, but laboratory tests show PFAS levels above the health advisory limit set by the Environmental Protection Agency.
To win a liability case, the well owner must prove that the defendant’s actions caused the contamination and that the contamination harmed the owner. The legal theories available are the same ones used in other pollution cases. Negligence requires showing that the defendant failed to act with reasonable care. For example, a factory that knew it was discharging PFAS into the ground but did not install proper containment could be negligent. Nuisance law applies when a defendant’s activity unreasonably interferes with the plaintiff’s use of their property—such as making a well undrinkable. Trespass covers actual physical invasion of the property by the contaminants. Strict liability is the most powerful claim: certain activities, such as handling hazardous chemicals, are so dangerous that a defendant can be held responsible even if they took every possible precaution. In many states, PFAS may qualify as an abnormally dangerous activity, which would allow a well owner to win without proving carelessness.
Proving causation is the hardest part. The well owner must show that the PFAS in their water came from the defendant’s site, not from some other source. This usually requires groundwater modeling, chemical fingerprinting that compares the PFAS mixture in the well to the mixture at the source, and expert testimony. The defendant will argue that there are other possible sources—nearby farms, septic systems, or even atmospheric deposition. The plaintiff must rule out these alternatives with solid evidence. This is why many PFAS cases are brought as class actions or consolidated suits, so the costs of expert studies are shared.
A major obstacle in PFAS liability cases is the statute of limitations. Most states require that a lawsuit be filed within a few years of when the injury was discovered or should have been discovered. Since PFAS has been used for decades, many well owners may have had contamination for years without knowing it. Courts are still sorting out when the clock starts—on the day the well owner first read about PFAS in the news, or the day they received a test result. Delayed discovery can cut off a claim entirely.
Another hurdle is the government contractor defense. If the source of contamination is a military base, the contractor that supplied the firefighting foam may argue that it was following government specifications and cannot be sued. This defense has had mixed results in PFAS litigation. Some courts have rejected it because the government did not specifically require the use of PFAS—it required a foam that worked, and the manufacturer chose the chemical composition.
Even with these challenges, success is possible. Several high‑profile cases have resulted in settlements. The town of Hoosick Falls, New York, reached a multimillion‑dollar settlement with Saint‑Gobain Performance Plastics after PFAS from a plastics plant contaminated private wells. In another case, a Michigan family won a jury verdict against a Wolverine Worldwide tannery that had dumped PFAS‑laced waste into a dump, tainting nearby wells. The verdict included compensation for diminished property value, past and future medical monitoring, and emotional distress.
For a private well owner considering legal action, the immediate priority is to get the water tested by a certified lab that can detect PFAS down to parts per trillion. Then consult an attorney who specializes in environmental torts. The attorney will evaluate the strength of the source link, the applicable statute of limitations, and the best legal theory. While PFAS litigation is expensive and time‑consuming, it is one of the few tools available to force polluters to clean up a problem they created. No one should have to drink contaminated water because a company made a product that did not break down.
