Nearly Half of U.S. Drinking Water Contains PFAS: USGS Study

A new report from the U.S. Geological Survey has found that at least 45% of tap water in the country contains PFAS, or per- and polyfluorinated alkyl substances. The study is the first to test for PFAS broadly across the country in both regulated public drinking water and private wells.

USGS tested for 32 types of PFAS, which have earned the name “forever chemicals” because they break down extremely slowly. According to Clean Water Action, some PFAS may take up to 8 years to break down in human bodies, and PFAS Free reported that some types can take up to 1,000 years to degrade in soil. These chemicals can be found in everything from weatherproof clothing and gear to nonstick cookware to firefighting foam.

This is not the first time that PFAS have been detected in drinking water. In March 2023, the U.S. Environmental Protection Agency even proposed the first PFAS limits for potable water. The results of that proposal are expected in 2024, The Associated Press reported. But the new USGS report shows how widespread these compounds are across the country, whether in public water supplies or private wells.

The researchers tested for 32 different PFAS compounds from tap water samples in 716 locations from 2016 to 2021, and they most frequently found perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS) and perfluorooctanoic acid (PFOA) in the samples. 

According to the American Cancer Society, both animal and human studies found potential links between PFOA exposure and increased risks of certain types of cancer, including testicular and kidney cancers. But more research is needed to determine the health risks of these chemicals.

“USGS scientists tested water collected directly from people’s kitchen sinks across the nation, providing the most comprehensive study to date on PFAS in tap water from both private wells and public supplies,” Kelly Smalling, lead author of the study and USGS research hydrologist, said in a news release. “The study estimates that at least one type of PFAS — of those that were monitored — could be present in nearly half of the tap water in the U.S. Furthermore, PFAS concentrations were similar between public supplies and private wells.” 

The results showed that the most PFAS exposure was around highly populated areas and in places near potential PFAS sources, like industrial sites or waste areas. Some areas in the study with the most PFAS exposure in the drinking water included the Great Plains, the Great Lakes area, the Eastern Seaboard, central California and southern California.

The USGS recommended for those who want to test their own drinking water for PFAS to contact local or state governments for how to do so. The USGS cannot make recommendations for policies on PFAS, but Smalling told The Associated Press that the results of the report “can be used to evaluate risk of exposure and inform decisions about whether or not you want to treat your drinking water, get it tested or get more information from your state.”