What are PFAS and why are they called 'forever chemicals'?

PFAS (per- and polyfluoroalkyl substances) are a class of over 12,000 synthetic chemicals characterized by extremely strong carbon-fluorine bonds that do not break down in the environment or in the human body under normal conditions. They have been used since the 1940s in non-stick cookware, stain-resistant textiles, food packaging, and AFFF firefighting foam. Because they persist indefinitely in the environment and accumulate in living organisms, they have been nicknamed 'forever chemicals.'

What is the EPA limit for PFAS in drinking water?

The EPA finalized Maximum Contaminant Levels (MCLs) for PFAS in April 2024 — the first federal enforceable limits for PFAS in drinking water. The MCL is 4 parts per trillion (ppt) for PFOA and PFOS individually — the most protective drinking water standard ever set. The EPA also set limits for PFNA (10 ppt), PFHxS (10 ppt), HFPO-DA/GenX (10 ppt), and a hazard index for mixtures. Public water systems must comply by 2027. The MCLG (the goal, not just the limit) is zero for PFOA and PFOS.

Where does PFAS in drinking water come from?

The two dominant sources of PFAS in U.S. drinking water are: (1) Military installations — AFFF (aqueous film-forming foam) used at Air Force, Navy, and Army installations for aircraft fire suppression and fire training has contaminated groundwater at hundreds of U.S. military bases over the past 60 years. This is the largest single category of PFAS contamination. (2) Industrial manufacturing — 3M, DuPont/Chemours, Saint-Gobain, Tyco Fire Products, and dozens of other manufacturers produced or used PFAS chemicals and discharged them into the environment.

Which states have the most serious PFAS contamination?

States with the most documented PFAS contamination include Michigan (Wolverine World Wide/Rockford and Wurtsmith AFB), Minnesota (3M East Metro), New York (Hoosick Falls, Newburgh, Long Island), New Jersey (DuPont legacy, military bases), Pennsylvania (Horsham/Warminster military cluster), North Carolina (Chemours Fayetteville Works/Cape Fear River), West Virginia (DuPont Washington Works), Colorado (Peterson/Buckley/Schriever Air Force bases), Massachusetts (Otis/Cape Cod, South Weymouth NAS), and New Hampshire (Saint-Gobain Merrimack, Pease ANG Base).

Does PFAS have health effects?

Yes — PFAS are associated with serious health effects at very low concentrations. The EPA's 2024 PFAS MCL is based on evidence linking PFAS exposure to kidney cancer, testicular cancer, thyroid disease, immune system suppression (including reduced vaccine effectiveness), high cholesterol, pregnancy complications, and developmental effects in children. PFOA and PFOS are classified as possible human carcinogens. The MCLG of zero for PFOA and PFOS reflects the scientific conclusion that there is no safe level of exposure.

Does a Brita or standard pitcher filter remove PFAS?

Most standard pitcher filters provide limited PFAS reduction but are not certified for PFAS removal. For reliable protection: (1) Reverse osmosis systems certified to NSF/ANSI 58 remove 90–99% of PFAS. (2) Under-sink activated carbon block filters certified to NSF/ANSI 53 or 58 for PFAS reduction provide significant removal. Always verify the specific product's NSF certification for PFAS — a general carbon filter claim is not sufficient. Replace filters on schedule.

Does boiling water remove PFAS?

No. Boiling does not remove PFAS. Because PFAS chemicals have high thermal stability (that's one reason they were commercially valuable), boiling has no significant effect on PFAS concentrations. Boiling can actually concentrate PFAS slightly by reducing water volume through evaporation.

How do I know if my water has PFAS?

Request your utility's most recent Consumer Confidence Report (CCR) — it is required to be sent to customers annually and must include PFAS monitoring results. Under EPA's UCMR5 program, public water systems have been required to test for PFAS since 2023. For private well owners, PFAS is unregulated — you must order a certified lab test yourself. State-certified labs typically charge $150–$400 for a PFAS panel covering multiple compounds.

Critical Risk LevelForever Chemicals

PFAS in Drinking Water

PFAS — per- and polyfluoroalkyl substances — are synthetic chemicals used for decades in industrial and military applications. They do not break down in the environment or the human body. In April 2024, the EPA finalized the first federal drinking water standard for PFAS: 4 parts per trillion for PFOA and PFOS.

Source: EPA, CDC, USGS · Last reviewed: 2025-01-01 · Data: official EPA SDWIS records

Quick Answer

Is PFAS in drinking water a real concern in the U.S.?

Yes — PFAS contamination of U.S. drinking water is one of the most significant public health issues in the country. The EPA's own data from the UCMR5 monitoring program found PFAS at detectable levels in approximately 45% of U.S. public water systems tested. PFAS from military AFFF foam and industrial manufacturing has contaminated groundwater near hundreds of installations and facilities. The EPA's 2024 MCL of 4 ppt for PFOA and PFOS — the most protective water standard ever set — will require hundreds of utilities to install new treatment.

Key Facts

EPA MCL (PFOA, PFOS)	4 ppt (parts per trillion) — finalized April 2024; utilities must comply by 2027
EPA MCL (PFNA, PFHxS, HFPO-DA/GenX)	10 ppt each — also part of the 2024 final rule
MCLG (health goal)	Zero for PFOA and PFOS — no safe level established
Primary source in water	AFFF firefighting foam at military bases and airports; industrial manufacturing (3M, DuPont, Chemours, Saint-Gobain)
Does boiling help?	No — boiling concentrates PFAS. Use certified reverse osmosis or activated carbon.
Effective treatment	NSF/ANSI 58 certified reverse osmosis (90–99% removal); NSF/ANSI 53/58 certified activated carbon
Compliance deadline for utilities	2027 — public water systems must meet the 4 ppt MCL
Private wells	Unregulated — owners near military bases or industrial sites should test independently

What Are PFAS?

A class of over 12,000 synthetic chemicals

PFAS is not a single chemical — it is a family of substances all sharing the carbon-fluorine bond structure. The most studied are PFOA (used in Teflon manufacturing) and PFOS (used in 3M Scotchgard). Newer 'short-chain' PFAS and 'next-generation' replacements like HFPO-DA (GenX) are now also regulated.

AFFF firefighting foam — the dominant contamination source

Aqueous Film-Forming Foam was standard firefighting equipment at U.S. Air Force, Navy, and Army installations from the 1970s onward. Fire training exercises and aircraft emergency responses used enormous quantities of AFFF, which soaked into soil and groundwater. The DoD has identified over 700 installations with known or suspected PFAS contamination.

Industrial manufacturing

3M manufactured PFOA and PFOS for decades at its Cottage Grove, MN facility. DuPont used PFOA to manufacture Teflon at its Washington Works plant in Parkersburg, WV. Saint-Gobain used PFAS in industrial tape manufacturing in Merrimack, NH and Bennington, VT. These industrial sources contaminated communities near their facilities.

Health effects at extremely low concentrations

The EPA's 2024 MCL of 4 ppt reflects evidence that PFAS causes harm at concentrations measured in parts per trillion — equivalent to about 4 drops in an Olympic swimming pool. Health effects linked to PFAS include kidney and testicular cancer, thyroid disruption, immune suppression, high cholesterol, and developmental effects in children.

PFAS in Drinking Water by State

State-specific guides covering local contamination sources, utilities, regulatory context, and resources.

Frequently Asked Questions

Data Sources & Provenance

All data on this page is sourced from official U.S. government or public datasets.

EPA — PFAS Drinking Water RegulationView source

EPA — Final PFAS National Primary Drinking Water Regulation (April 2024)View source

CDC — PFAS and Your HealthView source

EPA SDWIS — Violation and Compliance DataView source

EWG PFAS Contamination MapView source

Last updated: 2025-01-01

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