New maps reveal concerning findings about Americans' tap water — and it's just the tip of the iceberg

New national maps from the Natural Resources Defense Council (NRDC) based on Environmental Protection Agency data confirm that harmful PFAS "forever chemicals" have been found in tap water above safety limits in 47 states.

Arkansas, Hawai'i, and North Dakota were the only regions that tested at legally safe levels. The District of Columbia and all U.S. territories apart from American Samoa were also found to have contaminated tap water above safety thresholds.

Overall, 79% of congressional districts have tap water above EPA thresholds for PFAS.

What's happening?

PFAS, or per- and polyfluoroalkyl substances, are a group of synthetic chemicals used in products like nonstick pans, waterproof materials, and food packaging. Because they don't break down naturally, PFAS build up in the environment and subsequently in our bodies. One University of Cambridge study found that PFAS bioaccumulate in human gut bacteria.

Over 73 million people are already known to get tap water from systems that tested above EPA's safety levels, and tens of thousands of systems haven't reported results yet.

When unregulated PFAS are accounted for, nearly half of the 280 million people (about 136 million) whose water has been tested were served by systems with some level of PFAS contamination.

That number could grow as ongoing testing continues throughout this year, and this data is critical for making informed decisions about PFAS and understanding the contents of the water we consume.

Why is PFAS in water important?

PFAS have been linked to cancer, liver and kidney damage, hormone disruption, and weakened immune systems, according to the EPA. Even extremely low levels of exposure to PFAS can be harmful to human health, per an NRDC article.

Because PFAS are used so widely, they've already been detected in the blood of nearly every American in studies done as part of the National Health and Nutrition Examination Survey.

In April 2024, the EPA set new national standards limiting six PFAS in drinking water, but by May 2025, under industry pressure, the agency announced plans to delay or roll back those standards, which experts warn could leave millions unprotected.

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What's being done about PFAS?

While PFAS may seem ubiquitous and daunting to tackle, individuals can make a difference at many levels.

At home, using certified water filters and avoiding products with PFAS (like stain-resistant fabrics and nonstick pans) can reduce exposure.

People can help by supporting politicians who defend clean water standards. Groups like NRDC and the Environmental Working Group are pushing back legally and demanding more regulations on the harmful chemicals, as well as informing consumers on how to avoid them.

As testing expands and the laws around PFAS change, it is crucial to stay informed, be vocal, and reduce household exposure to PFAS to protect the safety of you and those you care about.

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