⚠ Forever chemicals

PFAS Contamination Map

PFAS are synthetic chemicals that never break down in the environment or the human body. In 2024 the EPA set the first-ever enforceable limits — but millions of Americans are already over them. See how every state compares.

1,621

Cities exceeding EPA PFAS limits

7,752

Cities with PFAS testing data

13,858

Individual PFAS compound detections

4 ppt

EPA limit for PFOA & PFOS (2024)

0%10%25%40%55%+ No data

Percentage of tested cities exceeding EPA PFAS maximum contaminant levels

⚠

200+ million Americans may be drinking water contaminated with PFAS, according to a 2023 USGS study — the largest national survey of PFAS in tap water ever conducted. The study found PFAS at detectable levels in 45% of US tap water samples.

PFAS contamination: key numbers

12,000+

Distinct PFAS compounds ever manufactured since the 1940s

700+

US military installations with confirmed PFAS groundwater contamination from AFFF foam

45%

Of US tap water samples had detectable PFAS — 2023 USGS national survey, the largest ever conducted

4 ppt

EPA's maximum contaminant level for PFOA and PFOS set in April 2024 — down from a 70 ppt advisory in 2016

PFAS compounds tested under EPA's UCMR 5 program (2020–2023), powering the data on this map

$2.3B/yr

EPA's estimated annual compliance cost for utilities to meet the 2024 PFAS rule

States ranked by PFAS exceedance rate

Percentage of tested cities where at least one PFAS compound exceeds the 2024 EPA maximum contaminant levels. The EPA MCLs: 4 ppt for PFOA, 4 ppt for PFOS, and a hazard index of 1.0 for mixtures of PFHxS, PFNA, PFBS, and GenX chemicals.

#	State	Cities exceeding	Cities tested	Exceedance rate	Avg Hazard Index
1	New Jersey	289	372	78%	3.86
2	Connecticut	94	128	73%	4.16
3	Delaware	13	25	52%	5.4
4	Florida	122	262	47%	5.57
5	South Carolina	52	116	45%	4.58
6	Massachusetts	103	238	43%	3.1
7	North Carolina	91	213	43%	4.94
8	Rhode Island	13	30	43%	2.41
9	New Hampshire	15	44	34%	2.28
10	Pennsylvania	81	267	30%	5.76
11	Alabama	62	232	27%	5.79
12	California	124	466	27%	5.44
13	Maryland	13	55	24%	4.65
14	Georgia	37	196	19%	4.57
15	West Virginia	17	92	18%	7.36
16	Ohio	44	258	17%	2.51
17	Arizona	18	112	16%	6.23
18	Kentucky	29	177	16%	2.49
19	Tennessee	35	218	16%	3.65
20	Washington	26	158	16%	4.59

How we got here: PFAS regulation timeline

PFAS contamination was known to industry decades before regulators acted. This is the timeline of how "forever chemicals" went from a trade secret to the EPA's most significant new drinking water rule in decades.

1940s PFAS first manufactured

3M and DuPont begin producing PFOS and PFOA for non-stick coatings (Teflon), stain-resistant textiles (Scotchgard), and AFFF firefighting foam used at military bases and airports. Internal company studies show toxicity in animals — findings are not shared with regulators for decades.

2000 3M voluntarily phases out PFOS production

Under EPA pressure, 3M agrees to phase out PFOS after internal documents reveal it accumulates in human blood worldwide. By this point, 3M's Minnesota manufacturing sites had already contaminated drinking water for hundreds of thousands of residents at levels thousands of times higher than current safety thresholds. 3M would eventually pay $850M to settle with Minnesota in 2018.

2006 DuPont settles Parkersburg contamination lawsuit — $107M

DuPont agrees to pay $107M over PFOA contamination from its Washington Works plant in Parkersburg, WV, which contaminated drinking water for 80,000 residents for decades. An independent scientific panel later linked PFOA exposure to kidney cancer, testicular cancer, thyroid disease, ulcerative colitis, high cholesterol, and pregnancy-induced hypertension. This case inspired the film "Dark Waters" (2019).

2016 First EPA lifetime health advisories — 70 ppt combined

EPA sets non-enforceable lifetime health advisory levels of 70 ppt combined for PFOA and PFOS — the first federal guidance for these chemicals in drinking water. Utilities above this level must notify customers but are not legally required to treat the water. Hundreds of water systems across the country discover they are above this advisory level.

2022 EPA revises advisories to near-zero levels

EPA updates interim health advisories to 0.004 ppt for PFOA and 0.02 ppt for PFOS — near the detection limit of most laboratory equipment. The reduction from 70 ppt to sub-part-per-trillion levels reflected updated cancer potency assessments and immune suppression data. These advisories are still not legally enforceable.

2020–2023 UCMR 5 national testing program reveals full scope

EPA requires all public water systems serving 3,300+ people to test for 29 PFAS compounds under the Unregulated Contaminant Monitoring Rule. Results confirm PFAS contamination is a nationwide problem — not limited to known industrial and military hotspots. The data from UCMR 5 powers this map.

Apr 2024 First-ever enforceable PFAS Maximum Contaminant Levels

EPA finalizes binding MCLs: 4 ppt for PFOA individually, 4 ppt for PFOS individually, 10 ppt for PFHxS, PFNA, and GenX (HFPO-DA), and a hazard index of ≤1.0 for mixtures of PFAS. Water systems must complete testing by 2027, notify customers of exceedances by 2028, and achieve full compliance by April 2029. The EPA estimates 66–77 million Americans are served by systems that will require treatment upgrades to comply.

Understanding PFAS in drinking water

What are PFAS?

PFAS (per- and polyfluoroalkyl substances) is an umbrella term for over 12,000 synthetic chemicals manufactured since the 1940s. They're used in non-stick cookware, waterproof clothing, stain-resistant fabrics, food packaging, and firefighting foam (AFFF). The carbon-fluorine bond — one of the strongest in chemistry — means they resist heat, water, and biological breakdown. They persist in soil and groundwater for decades and accumulate in human tissue over a lifetime.

Health effects

The EPA classifies PFOA and PFOS as probable human carcinogens. At concentrations as low as 1–2 ppt, studies link PFAS exposure to kidney and testicular cancer, thyroid disease, immune system suppression (including reduced vaccine effectiveness), elevated cholesterol, pregnancy complications including preeclampsia, and developmental delays in children. PFAS cross the placenta and are present in breast milk, making prenatal exposure a particular concern.

Major contamination hotspots

The worst PFAS contamination clusters around military bases where AFFF firefighting foam was used for decades — over 700 military installations have confirmed PFAS contamination. Industrial sites including chemical plants (DuPont's Teflon production in Parkersburg, WV; 3M plants in Alabama; chemours facilities in NC), airports, and firefighting training facilities are major point sources. Cape Fear River in North Carolina, contaminated by Chemours, became a landmark PFAS case in 2017.

The 2024 EPA PFAS rule

Finalized April 10, 2024, the rule sets the first-ever enforceable Maximum Contaminant Levels (MCLs): 4 ppt for PFOA and PFOS individually; 10 ppt for PFHxS, PFNA, and HFPO-DA (GenX); and a hazard index of 1.0 for mixtures. Water systems must test by 2027, notify the public by 2028, and comply by 2029. The EPA estimates 66–77 million Americans are served by systems that will need treatment upgrades to comply.

How PFAS gets into tap water

PFAS contaminate drinking water primarily through two pathways: industrial discharge into rivers and groundwater that feed surface water intakes, and direct groundwater contamination from AFFF use at military bases and airports. Landfill leachate from products containing PFAS is a growing secondary source. Unlike many contaminants, PFAS do not naturally attenuate in groundwater, meaning contamination from decades-old sources remains active today.

Removing PFAS from water

Reverse osmosis (RO) removes 90–99% of PFAS compounds and is the most effective point-of-use option. Granular activated carbon (GAC) filtration, used in most municipal treatment upgrades, removes 70–99% depending on PFAS chain length and contact time — long-chain PFAS like PFOA and PFOS are more effectively removed than short-chain variants. Ion exchange (IX) resin systems achieve 95–99% removal and are increasingly used by utilities. Standard pitcher filters with basic carbon offer limited protection and aren't recommended for high PFAS areas.

Which filters actually remove PFAS?

Not all water filters remove PFAS effectively. Boiling water makes it worse by concentrating PFAS as water evaporates. Look for filters certified to NSF/ANSI 58 (reverse osmosis systems) or NSF/ANSI 53 with explicit PFAS certification.

Filter type	PFAS removal	Long-chain (PFOA/PFOS)	Short-chain PFAS	NSF certification	Typical cost
Reverse osmosis (RO)	90–99%	Excellent	Excellent	NSF/ANSI 58	$150–$600 under-sink
Ion exchange (IX resin)	95–99%	Excellent	Good	NSF/ANSI 53 or 58	$200–$800 under-sink
Granular activated carbon (GAC)	70–99%	Good–Excellent	Fair	NSF/ANSI 53	$50–$300 countertop/under-sink
Pitcher filter (carbon block)	Limited	Fair	Poor	Varies — check label	$25–$60 + replacements
Refrigerator filter	Not recommended	Poor	Poor	Not PFAS-certified	$30–$60 replacement
Boiling water	Concentrates PFAS	Makes worse	Makes worse	N/A	—

Frequently asked questions

Is my PFAS exposure dangerous if levels are below the EPA limit?

The 4 ppt EPA limit represents the level at which health risk becomes significant enough to require regulatory action — not a threshold below which there is zero risk. Many health scientists argue that even lower levels cause harm, particularly for vulnerable populations including pregnant women, infants, and immunocompromised individuals. PFAS bioaccumulate over a lifetime, so chronic low-level exposure from water adds to exposure from food, cookware, and consumer products.

Why do some states have no PFAS data?

PFAS data comes from the EPA's UCMR 5 program, which tested public water systems serving 3,300+ people between 2020 and 2023. Smaller systems, private wells, and some rural utilities were not required to test. States shown in gray may have some testing but not enough data to calculate a reliable exceedance rate, or their water systems predominantly fall below the UCMR 5 size threshold.

How long will it take for utilities to comply with the 2024 rule?

Water systems have until 2029 to meet the new MCLs — a 5-year compliance window after the rule was finalized. However, systems must complete testing by 2027 and notify consumers of exceedances starting 2028. Installing GAC or RO treatment at a utility scale typically takes 2–4 years and costs millions of dollars. The EPA estimates total industry compliance costs of $1.5–$3.1 billion annually.

Do water filters in refrigerators remove PFAS?

Standard refrigerator filters use basic activated carbon and are certified to remove chlorine taste and some contaminants, but most are not certified for PFAS removal. Look for filters with NSF/ANSI 58 (reverse osmosis) or NSF/ANSI 53 certification specifically for PFAS. A dedicated under-sink RO system is more reliable than a refrigerator filter for PFAS removal.

Check PFAS levels in your city

Search for your city to see specific PFAS compounds detected, concentrations vs. EPA limits, and filter recommendations tailored to your water supply.

Search your city