What is Perfluorooctanoic acid (PFOA)* and Why Does It Matter?

PFOA: The "Forever Chemical" Hiding in Millions of Americans' Tap Water

PFOA (perfluorooctanoic acid) is a man-made chemical that doesn't break down in the environment — or in your body. It belongs to a larger family of chemicals called PFAS (per- and polyfluoroalkyl substances), which manufacturers have used for decades to make products like non-stick cookware, stain-resistant fabrics, food packaging, and firefighting foam. When these products are made, used, or disposed of, PFOA can leach into soil and groundwater. Industrial facilities, military bases, and airports that used PFAS-based fire suppressants are among the most common sources of contamination. Once PFOA enters a water source, it travels easily and lingers for years.

The health concerns around PFOA are serious and well-documented. The EPA classifies PFOA as a likely human carcinogen. Research linked to long-term exposure includes kidney cancer, testicular cancer, thyroid disease, high cholesterol, immune system disruption, and developmental problems in children (EPA, EWG). What makes PFOA especially concerning for families is that it accumulates in the body over time. Even low-level exposure adds up. Children are particularly vulnerable because their immune and hormonal systems are still developing.

Right now, 1,048 water systems across the United States have detected PFOA in tap water. Of those, 1,020 — nearly 97% — exceed the EWG health guideline of 0.1 parts per trillion (ppt). The average detected level across those systems is 2.314 ppt, and the highest recorded level reached 95 ppt. The EPA set a Maximum Contaminant Level (MCL) of 4 ppt for PFOA in 2024, which is stricter than older standards but still 40 times higher than what EWG considers safe based on current health research. Essentially, water that meets the legal limit can still pose a meaningful health risk, especially for pregnant women, infants, and young children.

Geographically, PFOA contamination is concentrated in states with heavy industrial activity, military installations, or legacy manufacturing. New York leads the country with 183 affected water systems, followed closely by North Carolina with 160. Illinois, Texas, and South Carolina round out the top five, with 71, 68, and 62 affected systems respectively. New York's numbers reflect decades of industrial manufacturing in the Hudson Valley and Long Island regions. North Carolina's contamination is tied in large part to PFAS manufacturing facilities in the Cape Fear River basin — an area that has drawn national attention in recent years. That said, PFOA has been found in water systems across nearly every state, so no region is entirely off the hook.

The good news is that effective filtration options exist. Reverse osmosis (RO) filtration is the most reliable method for removing PFOA from drinking water, capable of eliminating up to 99% of PFAS compounds, including PFOA (NSF International). Activated carbon filters — particularly those using granular activated carbon (GAC) — can also reduce PFOA levels, though they are generally less effective than RO systems at very low concentrations. Standard pitcher filters and basic faucet attachments typically do not remove PFOA adequately. If your home is in one of the high-risk states, or if you're simply not sure what's in your water, the most important first step is to test your water. Echo Water's at-home testing options can show you exactly what you're dealing with — so you're making decisions based on your actual water, not a regional average. From there, a whole-home or under-sink RO system gives you a consistent, measurable layer of protection for the water your family drinks every day.

Regulatory Standards for Perfluorooctanoic acid (PFOA)*

Cities With the Highest Perfluorooctanoic acid (PFOA)* Levels

States Most Affected by Perfluorooctanoic acid (PFOA)*

Frequently Asked Questions

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