Find out which U.S. cities have detected ‘forever chemicals’ in their drinking water

Millions Exposed to Harmful ‘Forever Chemicals’ in Tap Water, EPA Data Shows

Tap water used by at least 42 million Americans contains unsafe levels of so-called “forever chemicals,” according to a new USA TODAY analysis of data released by the Environmental Protection Agency (EPA) on June 2.

Known as PFAS (per- and polyfluoroalkyl substances), these manmade chemicals are nearly impossible to break down and can build up in the human body over time, potentially causing cancers, liver damage, and other serious health issues.

Over the past two years, the EPA has gathered full test results from roughly 6,900 water systems, with thousands more pending as part of an ongoing national testing effort.

USA TODAY’s analysis reveals that nearly 1 in 4 large utilities—those serving 100,000 people or more—exceeded federal safety limits on PFOS and PFOA, two of the most dangerous PFAS compounds.

Among the largest systems newly identified with high PFAS levels are Fairfax County, Virginia, and San Juan, Puerto Rico, each serving over a million residents. Also added to the list is Tempe, Arizona, where PFOS levels at one testing site reached 55 parts per trillion (ppt)—well above the EPA’s safety limit of 4 ppt.

In total, 774 water systems across the country currently fail to meet federal PFAS standards. These systems will likely be required to install advanced filtration technology or secure new water sources by 2031.

The compliance deadline was initially set for 2029, but in May, the EPA proposed a two-year extension and indicated it would roll back PFAS limits set in 2024 for four additional chemical variants.

EPA Administrator Lee Zeldin defended the move as a way to offer “common-sense flexibility” to help both large and small water systems—especially in rural communities—navigate the costly and complex remediation process.

However, the rollback has drawn legal and political backlash. Water industry groups have filed suit against the EPA, claiming it sidestepped the Safe Drinking Water Act’s legal procedures in setting the original limits. The lawsuit has been on hold since February and was extended again on June 4 through July 21 as the new administration evaluates its next steps.

Public health advocates have sharply criticized the EPA’s direction. Melanie Benesh, vice president of government affairs at the Environmental Working Group, called the delay and rollback efforts a “public health betrayal.”