Almost half of U.S. tap water contains ‘forever chemicals’

By E.A. Crunden | 07/05/2023 04:34 PM EDT

In a first-of-its-kind study, the U.S. Geological Survey determined that at least 45 percent of water supplies are polluted with PFAS.

A glass of drinking water.

A new study from the U.S. Geological Survey finds that almost half of U.S. tap water systems contain PFAS. Engin Akyurt/Unsplash

The most high-profile chemicals under fire from the Biden administration likely permeate almost half of U.S. tap water systems, according to a new study from the U.S. Geological Survey that raises yet more concerns about the sprawling family of compounds.

The first-of-its-kind report offers yet more ammunition to regulatory proponents who have pushed for a strong-armed approach to cracking down on PFAS. Their push has already sparked significant results, with the Biden administration tackling the chemicals through a range of statutes as regulators seek to bring the crisis under control.

In the report released Wednesday, scientists found that both private and government-regulated public water sources contain one or more types of PFAS. That proliferation extends to “at least 45% of the nation’s tap water,” according to USGS estimations, with the number possibly higher.


USGS research hydrologist Kelly Smalling, the study’s lead author, said in a statement that the findings offer unique insight into the extent of pollution from per- and polyfluoroalkyl substances nationwide.

The scientists, Smalling said, “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.”

While EPA regulates public water utilities, homeowners are responsible for the testing and upkeep of private sources. USGS scrutinized each type of water system, while testing for 32 PFAS compounds. The family spans more than 12,000 chemicals, according to some estimates, but detecting many of them can be a challenge given limited technology and understanding around those substances.

Using a method developed by the USGS National Water Quality Laboratory, the scientists detected a range of compounds. Seventeen chemicals were identified at least once, while the most frequently detected compounds are among the most alarming that scientists have studied to date: PFOA, PFBS and PFHxS.

All three of those chemicals are under major scrutiny from regulators. PFOA is considered a likely carcinogen and was phased out of U.S. production years ago due to its major health concerns, spanning from liver and kidney disease to reproductive and developmental problems. PFBS and PFHxS are also among compounds the Biden administration has sought to regulate in drinking water due to alarming research around their own health implications.

Although the presence of those compounds in water systems has long been established, the USGS study sheds light on the sheer extent of the contamination. Scientists collected tap water samples from 716 locations, while working to represent areas described as having low, medium or high levels of human impact. A low categorization includes public lands offered some level of protection from people, while medium extends to residential and rural areas that are not known to have sources of PFAS contamination. Areas in the high category include urban settings and locations that have reported exposure from the chemicals, including industrial and waste facilities.

In accordance with the designations, the scientists noted higher levels of PFAS in urban areas, along with spots believed to be possible sources of the chemicals. The study noted that several regions registered as having outsize contamination, including the Great Plains and Great Lakes areas, as well as the Eastern Seaboard and both southern and central California. Cumulative concentrations of the chemicals, meanwhile, ranged from virtually undetectable amounts to a very high 346 parts per trillion.

Overall, USGS estimated that the probability of the compounds not being observed in tap water is about 75 percent in rural areas, while falling to around 25 percent in their urban counterparts.

“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.,” said Smalling. “Furthermore, PFAS concentrations were similar between public supplies and private wells.”

Those conclusions will likely add to mounting pressure on the Biden administration to tackle the chemicals.

Among the most sweeping moves to date is an ongoing plan to regulate six PFAS under the Safe Drinking Water Act. Under a draft debuted this spring, PFOA and another notorious compound, PFOS, would be capped at 4 ppt in drinking water — the lowest levels a lab can measure. PFHxS and PFBS are meanwhile among another four chemicals that would be grouped as a mixture and subject to cutoffs based on their hazards.

The USGS findings underscore just how challenging imposing those thresholds will be, given that much of the country’s water is impacted. Utilities have long asserted that the cost and feasibility of addressing the crisis will require significant aid from the government, with the burden otherwise set to fall on taxpayers. In the meantime, many have turned to litigation targeting chemical giants like 3M and DuPont as they seek damages, a trend that has spawned settlement agreements stretching upward of $12 billion.