You have probably heard of PFAS by now—the “forever chemicals” used in nonstick pans, waterproof jackets, firefighting foam, and countless industrial products. What makes them dangerous is also what makes them a legal nightmare: they do not break down in the environment. Once PFAS gets into the ground or the groundwater, it stays there for decades, moving slowly through the soil and spreading into wells, rivers, and drinking water supplies. When that happens, someone has to pay for the cleanup, and the law usually has a clear answer: the person or company that put the chemicals there, no matter how long ago it happened.

Environmental liability for groundwater and soil contamination involving PFAS works on a simple principle called strict liability. That means you do not have to prove that the polluter was careless or knew the chemicals were dangerous. If you can show that PFAS from a specific source ended up in your soil or groundwater, the person or company responsible for that source is legally on the hook for the cleanup costs. This is very different from most personal injury cases, where you have to show negligence. With PFAS contamination, the law treats the harm as so serious that the polluter is automatically liable just by releasing the chemical.

The dirty secret of PFAS litigation is that the damage is almost always widespread. A single industrial site that used PFAS in manufacturing can contaminate groundwater for miles around. A military base that used PFAS-containing firefighting foam can pollute the drinking water of entire towns. When that happens, multiple groups become liable: the company that made the PFAS, the company that bought it and used it, the company that disposed of waste containing PFAS, and sometimes the current owner of the contaminated land. The legal system in the United States uses a concept called joint and several liability, which means any one of those responsible parties can be forced to pay for the entire cleanup, even if they only contributed a small amount of the contamination. That party then has to sue the others to get their share back. It is messy, it is expensive, and it is why PFAS cases often take years to resolve.

For property owners, the big risk is that you might be liable even if you did not cause the problem. If you buy a piece of land and later discover PFAS in the soil or groundwater, you could be forced to clean it up simply because you now own the contaminated property. This is called owner liability. The only way to avoid it is to prove that you conducted a thorough environmental investigation before buying the land and that you had no reason to know the PFAS was there. This is why smart buyers always hire an environmental consultant to test soil and water before closing a deal.

The federal law that drives most of these cases is the Comprehensive Environmental Response, Compensation, and Liability Act, commonly called Superfund. Under Superfund, EPA can force the original polluter to clean up a site or reimburse the government for doing the work. For PFAS, the EPA has been slow to set a national cleanup standard, but several states have stepped in and created their own limits. If your property is in one of those states, the state environmental agency can sue you or the polluter for cleanup costs, and the clock starts ticking the moment contamination is discovered.

One of the hardest parts of PFAS liability is that the chemicals move through soil and water in unpredictable ways. A spill that happened twenty years ago might only show up in a neighbor’s well today. When that happens, the statute of limitations—the time limit for filing a lawsuit—starts when the contamination is discovered, not when it was released. That keeps the door open for lawsuits long after the original release.

If you find PFAS in your soil or groundwater, the first step is to document everything. Get laboratory tests that show the specific PFAS compounds present and their concentrations. Then track the source—often it is an old landfill, a former industrial site, or a fire training area. Once you have that evidence, you have a strong case for getting the responsible party to pay for a cleanup that can cost millions of dollars. The alternative is paying for it yourself, which is why PFAS contamination is one of the most expensive environmental liabilities in the country right now.