New Study Reveals 'Forever Chemicals' Present in Almost 50% of U.S. Tap Water

At least 45% of US drinking water is contaminated with per- and polyfluoroalkyl substances (PFAS), according to a new study from the US Geological Survey (USGS).

PFAS are manmade chemicals and are found in everyday items like non-stick cookware, some firefighting foams, stain-resistant carpets, and products that resist grease, water, and oil.

"Their persistence in the environment is why they are commonly called 'forever-chemicals'," said Kelly Smalling, MSPH, a USGS research hydrologist, and lead author of the new study. "And prevalence across the country make them a unique water-quality concern."

According to the National Institute of Environmental Health Sciences, there are more than 9,000 types of PFAS, and because they don't break down, they can build up over time in people, animals, and the environment.

Research has linked the exposure of PFAS to obesity, thyroid disease, cancer, high cholesterol, infertility, and liver damage.

Because these synthetic chemicals are so widespread, most people in the US have been exposed to some PFAS. Certain individuals are at a higher risk, such as workers who are involved in the process of making them, people who live near those facilities, and children.

There is ongoing research to determine how different levels of exposure to different PFAS might lead to a variety of health effects. Understanding how the tap water you drink is impacted by PFAS is a crucial step toward protecting yourself and your loved ones from harmful exposure.

Most state and federal water monitoring programs measure PFAS at the water treatment plants or groundwater wells that supply water, but the new study focused on collecting water directly from homeowners' taps, where exposure occurs.

USGS researchers tested tap water from 716 locations, including 269 private wells and 447 public supply sites, in all 50 states, Puerto Rico, the US Virgin Islands, and Washington D.C. between 2016 and 2021.

"Results from the USGS study show that PFAS were more frequently observed in samples collected near urban areas and potential sources of PFAS contamination, such as airports, industry, and wastewater treatment plants," Smalling said.

The highest concentration of PFAS in drinking water was found in the Great Plains, the Great Lakes, the Eastern Seaboard, and Central/Southern California.

The concentration of PFAS was similar between private wells and public supplies.

Based on their findings, the researchers estimate that at least one PFAS chemical would be detected in 45% of all US drinking water samples.

While the USGS, which describes itself as "the science arm of the Department of the Interior," doesn't offer recommendations in its report, Smalling encouraged individuals to empower themselves with information when it comes to knowing what's in their tap water.

"If the average American is worried about the quality of their drinking water, they can use this and other studies to get informed, evaluate their own personal risk, and reach out to their local health officials about testing or treatment," she said.

The Environmental Protection Agency is also collecting scientifically valid data on the national occurrence that 29 PFAS are found in the nation's drinking water systems and at what levels under the fifth Unregulated Contaminant Monitoring Rule (UCMR5).

Monitoring for the UCMR 5 began in 2023 and will continue through 2025.

The EPA expects to release the first results from the UCMR 5 this summer and to update this data quarterly. They also offer advice on in-home treatment options and testing in their factsheet for their proposal to limit PFAS in drinking water.

While the EPA recommends checking your tap water once a year, Jamie DeWitt, PhD, professor of pharmacology and toxicology at the Brody School of Medicine at East Carolina University who was not involved in the new study, says she looks at her water quality report sent to her through the utility that provides her drinking water for updates.

"It's probably not a bad idea to look at your utility's annual or quarterly reports," DeWitt said. "If you're a private well owner, it depends on the source of your well and what is around the well that could be contaminating it."

She also noted that people on private wells are responsible for testing their own water unless they live in an area that has been impacted by PFAS, or other chemicals or pathogens. In those cases, they might have their water tested or treated due to a court order or ruling.

Individuals can also install water filters that are designed to lower the levels of PFAS in water, using technologies like activated carbon treatment and reverse osmosis.

While you can test your tap water at home, if you’re curious how to ensure your drinking water in restaurants or other public spaces is safe, DeWitt says to proceed with caution.

“I think in this case, consumers will have to be aware and ask,” she said. “But I would like to think that if a business that serves water knows that it is contaminated, they would take steps to filter or offer alternative water.”