The National Resources Defense Council (NRDC) has created a comprehensive map, based on U.S. Environmental Protection Agency (EPA) data, that shows the extent of “forever chemical” contamination in U.S. drinking water—revealing that more than 73 million people are being served by water systems with contamination above now-revoked EPA maximum limits for any one of six problematic per- and polyfluoroalkyl substances (PFAS). In May 2025, EPA announced plans to partially roll back the Biden-era maximum limits, rescinding the regulations for four of the chemicals and delaying the compliance date for the remaining two PFAS types. NRDC experts say their map demonstrates how rolling back these drinking water limits will leave millions of Americans unprotected.

More specifically, in April 2024, EPA issued the first-ever national, legally enforceable drinking water standard to protect Americans from exposure to harmful PFAS:  PFOA, PFOS, PFNA, PFHxS, and HFPO-DA (also known as GenX chemicals), as well as a limit for mixtures of any two or more of four PFAS: PFNA, PFHxS, PFBS, and GenX chemicals. These PFAS types are known to cause harm to human health and for their widespread environmental contamination.

On May 14, 2025, Trump-appointed EPA Administrator Lee Zeldin announced that the agency would be rescinding the regulations for PFNA, PFHxS, GenX chemicals, and PFBS. EPA also extended the compliance deadline for PFOA and PFOS from 2029 to 2031.

Exposure to PFAS has been linked to cancer, impacts to the liver and heart, and immune and developmental damage to infants and children. PFAS are often referred to as “forever chemicals” due to their inability to break down in the environment or the human body.

According to NRDC’s map, which visualizes data from EPA’s Fifth Unregulated Contaminant Monitoring Rule (UCMR5) testing program, more than 73 million people are being served by water systems with water that had at least one UCMR5 test sample above the EPA’s PFAS threshold. Of those 73 million Americans, 30 million are served by water systems with PFAS concentrations exceeding limits for one of the four PFAS that EPA plans to roll back.

Moreover, when additional, unregulated PFAS are considered, the data shows that nearly half of the people across the U.S. whose water was tested under UCMR5 are supplied by systems that detected some level of PFAS. UCMR5 testing is ongoing, and the number of Americans exposed to high levels of PFAS through their drinking water may increase as additional results are released. 

View NRDC’s map here.