Study reveals US water contains twice as many PFAS chemicals

Drinking water across America might hold twice as many "forever chemicals" as official reports admit, a fresh study claims. Scientists combed through more than 1.8 million records from the Environmental Protection Agency tracking per- and polyfluoroalkyl substances, or PFAS, in public water systems nationwide. They discovered that classifying any PFAS levels below minimal reporting limits as zero causes current EPA data to capture only about 44 percent of the average concentration found in these systems. This gap means the true burden of these chemicals is likely far heavier than documents suggest.

PFAS linger for long periods and are increasingly linked to serious health problems like reproductive issues, liver damage, cancer, and developmental delays in children. The EPA data indicates at least 176 million Americans drink from systems where PFAS were detected. However, more than half of all test results fall below the agency's minimum reporting threshold and get treated as zero on official charts.

Gehendra Kharel, first study author and associate professor at Texas Christian University, explained how this practice distorts reality. "When the levels of these chemicals are below our reporting limit, it's often treated as zero when we calculate how widespread they are," he stated. "We set out to understand how treating those results as zero changes the picture of PFAS occurrence in drinking water." The team found the biggest gaps exist in California, followed by Texas and Florida, considering both chemical levels and population reliance on these systems.

Under the Safe Drinking Water Act, the EPA mandates that public water systems monitor 29 different kinds of PFAS. Their minimum reporting threshold sits at four parts per trillion. Most individual test results from the Environmental Working Group's dataset fall below this line, forcing the agency to record them as zero. Kharel noted this does not mean the water is completely free of chemicals, but agencies often ignore these sub-threshold findings when summarizing average levels.

Researchers analyzed data for 25 PFAS types with at least one national detection to estimate the difference between reported figures and their own model's findings. Overall, while conventional estimates put the national average concentration at about 2.6 nanograms per liter, this new study models an average closer to 5.2 nanograms per liter. A map included in the research highlights these differences, with darker shades marking states showing larger gaps between standard measures and actual findings.

The Environmental Working Group updated their data in March 2026 to show areas where PFAS levels measure above or below proposed safety limits. To reduce exposure risk, the EPA recommends drinking filtered water instead of tap sources. Researchers warn that health risks tied to PFAS are still being uncovered, and exactly how much chemical load links to long-term damage remains unclear. The urgency is high because treating low-level results as zero hides a massive portion of what people actually drink.

The EPA warns that tiny traces of PFAS build up inside us over months or years. These chemicals never break down. That slow accumulation drives high cholesterol, reproductive trouble, developmental delays, liver damage, and specific cancers. You need filtered water to lower your exposure right now.

Kharel says the new data isn't a call for panic yet. He explained that the study 'only estimates how PFAS measurements are summarized.' It 'does not establish that every below-limit result poses a health risk.' That distinction matters. We must understand what we actually know versus what remains unknown.

However, these findings offer a clearer picture of PFAS levels in our drinking water. Kharel pointed out something vital when reports say "not detected." That phrase means the amount fell below the reporting limit. It does not mean zero. Our method helps agencies and utilities account for that gap. Now they can see exactly where more testing would help. This approach clarifies what we do know and what we still need to find out. Time is short before these hidden risks grow larger.