PFAS in Drinking Water: How Forever Chemicals Enter Your Water Supply

The Scale of PFAS Water Contamination in America

PFAS contamination in U.S. drinking water is not a localized problem — it is a nationwide crisis. The Environmental Working Group's analysis of EPA testing data found that PFAS are detectable at some level in the water supplies of communities across all 50 states. More significantly:

• EPA's UCMR 5 program (2023–2025) found PFAS above detection limits in water systems serving over 200 million Americans
• Approximately 70 million Americans receive water from systems with PFAS above the new EPA Maximum Contaminant Levels (MCLs) of 4 parts per trillion
• Studies estimate that 45% of U.S. tap water samples have detectable PFAS levels
• PFAS have been detected in major river systems including the Ohio, Monongahela, Cape Fear, and Delaware rivers

How PFAS Gets Into Water Supplies

1. AFFF Firefighting Foam at Military Bases and Airports

The single largest source of PFAS groundwater contamination in the United States is AFFF (aqueous film-forming foam) used at military installations and civilian airports. When AFFF is deployed in fire training or actual fire suppression, the foam contains extremely high concentrations of PFOS and PFOA — which leach through soil and enter the groundwater. Communities drawing drinking water from contaminated aquifers often don't know they're exposed for years or decades.

2. Industrial Manufacturing Discharges

Facilities that manufacture or extensively use PFAS chemicals discharge contaminated wastewater into rivers, streams, and municipal sewer systems. Major contamination events include:

• DuPont Washington Works, Parkersburg, WV: Discharged PFOA (C8) into the Ohio River for decades, contaminating water supplies in six water districts serving 100,000+ people
• Chemours Fayetteville Works, NC: Discharged GenX chemicals into the Cape Fear River, contaminating water supplies for the Wilmington, NC region
• Saint-Gobain Performance Plastics, Hoosick Falls, NY: Contaminated the municipal water supply with PFOA from manufacturing operations
• Textile mills in NC and SC: Daikin and other manufacturers have discharged PFAS into local waterways

3. Biosolids (Sewage Sludge) Applied to Agricultural Land

PFAS from industrial wastewater accumulate in the biosolids (treated sewage sludge) produced by municipal wastewater treatment plants. These biosolids have been widely applied to agricultural fields as fertilizer for decades — spreading PFAS contamination into soil and groundwater across rural areas. This pathway has contaminated dairy farms in Michigan, Maine, and other states, with PFAS detected in milk and agricultural products.

4. Landfill Leachate

Consumer products containing PFAS — including food packaging, stain-resistant textiles, and nonstick cookware — end up in landfills. Water percolating through solid waste picks up PFAS and generates highly contaminated leachate that can migrate to surrounding groundwater if the landfill liner is compromised or absent.

5. Industrial Parks and Manufacturing Zones

Semiconductor manufacturers, chrome plating operations, and other industries use PFAS in their processes. Their discharges have contaminated water sources in Silicon Valley, the Research Triangle, and other industrial corridors.

EPA UCMR 5: What the Federal Data Shows

The EPA's Unregulated Contaminant Monitoring Rule (UCMR) is a program requiring public water systems to test for contaminants not yet subject to national drinking water standards. UCMR 5, implemented in 2023–2025, required testing for 29 PFAS compounds by water systems serving 3,300+ people.

The UCMR 5 data represents the most comprehensive PFAS monitoring dataset ever assembled for U.S. drinking water. Key findings:

• PFAS were detected in approximately 70% of water systems that reported data
• PFOA and PFOS were the most commonly detected compounds
• GenX chemicals were detected in water systems in North Carolina and surrounding states
• PFHxS was found at elevated levels in communities near military bases
• Water systems near military installations and industrial facilities showed the highest contamination levels

You can search the UCMR 5 database on the EPA's website to find results for your specific water system. If your system is listed with detections above the new MCLs, your community has confirmed PFAS exposure.

The 2024 EPA PFAS MCLs: A Historic Regulatory Step

In April 2024, the EPA finalized the first-ever legally enforceable Maximum Contaminant Levels (MCLs) for PFAS in drinking water:

• PFOA: 4 parts per trillion (ppt)
• PFOS: 4 parts per trillion (ppt)
• PFHxS, PFNA, HFPO-DA (GenX): 10 ppt each
• PFAS mixtures: Combined hazard quotient approach for PFHxS, PFNA, HFPO-DA, and PFBS

Water systems must comply by 2029. The EPA estimates that compliance will cost water utilities approximately $1.5 billion annually — which is why the 3M and DuPont settlements were structured to fund filtration infrastructure.

The significance of 4 ppt cannot be understated. For context: 4 parts per trillion is roughly equivalent to 4 drops of water in an Olympic-sized swimming pool. This is near the limit of laboratory detection — reflecting the EPA's conclusion that no safe level of PFOA or PFOS exposure has been established.

Does a High-Limit Filter Remove PFAS?

Standard pitcher filters and most carbon filters are NOT effective at removing PFAS from water. Effective PFAS removal requires:

• Granular activated carbon (GAC) filters — effective for some PFAS at high-dose systems
• Reverse osmosis (RO) systems — most effective for residential use, removing 90–95%+ of PFAS
• Nanofiltration — used at municipal scale
• Ion exchange (IX) resins — most effective for municipal-scale removal

For information on testing your current water, see our PFAS water testing guide.

Your Legal Rights If Your Water Was Contaminated

If your municipal water supply had confirmed PFAS contamination above EPA limits and you developed a PFAS-linked illness — kidney cancer, testicular cancer, thyroid disease, ulcerative colitis — you may have a valid personal injury claim against the companies that contaminated the water supply.

The fact that a water utility served contaminated water does not mean the utility is liable to you personally — the liability lies with the manufacturers and industrial polluters who put PFAS into the environment in the first place.