If your drinking water comes out of the tap contaminated with toxic chemicals that never break down in the environment, you have a legal problem. But more importantly, you have a question: who is legally responsible for cleaning it up and paying for the damage to your health and property? The answer is not simple, but it follows a few basic principles of environmental liability that any non-lawyer can understand.
Per- and polyfluoroalkyl substances, commonly called PFAS or forever chemicals, are a class of thousands of man-made compounds used in non-stick cookware, waterproof clothing, firefighting foam, food packaging, and industrial processes. They are called forever chemicals because they do not degrade naturally. They accumulate in soil, water, and living tissue, including the human body. Studies link high exposure to kidney cancer, testicular cancer, liver damage, thyroid disease, and immune system suppression. And they are now found in the drinking water supplies of millions of Americans.
When a water utility discovers PFAS in the community water system above the health advisory level set by the Environmental Protection Agency, the utility faces a choice: treat the water at enormous cost, find a new source, or face lawsuits from residents who drank the water. The same applies to private well owners who test their water and find contamination. The question of who pays turns on who caused the chemicals to get into the groundwater in the first place.
The core legal theory in these cases is product liability or negligence applied to environmental harm. The companies that manufactured PFAS, such as 3M, DuPont, and Chemours, knew for decades that these chemicals were toxic and persistent. Internal documents revealed in litigation show they hid the risks from regulators and the public. Under the law, a company that makes a defective product and fails to warn about its dangers can be held strictly liable for the harm that product causes. That means the victims do not have to prove the company was careless; they only have to prove the product was unreasonably dangerous and that they were injured by it.
But liability does not stop at the manufacturer. Companies that used PFAS in their operations, such as metal platers, paper mills, textile plants, and airports that used firefighting foam, can also be held responsible. When these operations released PFAS into the environment through wastewater, spills, or air emissions, they created a public nuisance. Under nuisance law, a party that substantially interferes with a public resource like groundwater can be ordered to stop the interference and pay for the damage. In many states, property owners also have a right to sue for trespass if the chemicals physically invaded their land.
The big challenge in these cases is proving which company’s chemicals caused the contamination in a specific well or water system. PFAS from multiple sources often mix in the aquifer. The law uses a concept called joint and several liability. In simple terms, if multiple parties contributed to a single harm that cannot be divided, each party can be held responsible for the entire cost. That puts pressure on the defendants to settle quickly rather than fight over who dumped how much. The defendants then sort out their shares among themselves, often through complex lawsuits called contribution actions.
In addition to lawsuits filed by individuals and water utilities, state and federal governments have stepped in. The EPA has designated certain PFAS as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act, also known as Superfund. That law gives the agency the power to order the responsible parties to clean up contaminated sites or reimburse the government for the cleanup costs. It also allows private parties who clean up voluntarily to sue the polluters to recover their costs. Superfund liability is strict, joint, and several, meaning it is one of the most powerful tools available.
But Superfund has limits. It applies to sites where hazardous substances have been released, not to every case of contaminated drinking water. And the process can take decades. In the meantime, water utilities and homeowners are stuck with the immediate cost of installing filtration systems or buying bottled water. Some utilities have tried to pass those costs onto ratepayers, leading to rate increases. That has triggered another kind of liability: if a utility fails to take reasonable steps to protect its customers from known contamination, it can be sued for negligence or breach of public trust.
Insurance also plays a role. Many companies that manufactured or used PFAS carry general liability policies that may cover environmental claims. But insurers have fought tooth and nail to deny coverage, arguing that PFAS contamination is a gradual pollution event excluded under standard policy language. Courts have split on this issue. Some hold that the contamination occurred at the time of the discharge, not gradually, so coverage applies. Others side with insurers. The outcome depends on the specific policy wording and state law.
The bottom line is this: liability for contaminated drinking water is built on a foundation of product defects, negligence, nuisance, trespass, and federal cleanup laws. The companies that made and used forever chemicals are on the hook, but actually getting them to pay requires evidence, aggressive litigation, and often government pressure. For the average person or small water system, the path to compensation is long, expensive, and uncertain. That is why class action lawsuits and mass tort cases have become the primary vehicle for holding polluters accountable. When thousands of victims join together, the cost of suing becomes manageable, and the pressure on defendants to settle becomes overwhelming.
