Is PFAS in my tap water?

Possibly. The EPA's UCMR 5 monitoring found PFAS in approximately 45% of U.S. tap water samples. The best way to know for certain is to check your utility's Consumer Confidence Report (CCR), search the EPA's PFAS Analytical Tools database, or order a certified lab test for your specific address.

What water filter removes PFAS?

Reverse osmosis (RO) systems are the most effective, removing 90–99% of PFAS compounds. Activated carbon filters certified to NSF/ANSI Standard 58 also provide significant reduction. Standard pitcher filters, sediment filters, and water softeners do NOT remove PFAS.

What is the EPA's new PFAS drinking water limit?

In April 2024, the EPA set MCLs of 4 parts per trillion (ppt) for PFOA and PFOS — the two most studied PFAS compounds. This is the first federal legal limit for any PFAS in drinking water. Water systems have until 2029 to comply.

Are PFAS only in public water systems?

No. Private wells can also be contaminated, especially near military bases, airports, or industrial sites. Unlike public water systems, private wells are not regulated by the EPA and are not required to be tested. If you have a private well near a known contamination site, testing is strongly recommended.

How do PFAS get into drinking water?

PFAS enter water supplies primarily through industrial discharge, firefighting foam use at military bases and airports, leaching from manufacturing facilities, and runoff from land treated with PFAS-contaminated biosolids. They are highly mobile in groundwater and surface water.

All Contaminants

high risk levelSynthetic ChemicalsRelevant to well water

Per- and Polyfluoroalkyl Substances (PFAS)

PFAS are a group of thousands of man-made chemicals that have been used in industrial and consumer products since the 1940s. They do not break down in the environment or the human body, earning the name 'forever chemicals.' In April 2024, the EPA set the first-ever federal limits for six PFAS compounds in drinking water.

Quick Answer

Per- and polyfluoroalkyl substances (PFAS) are a class of over 12,000 synthetic chemicals characterized by strong carbon-fluorine bonds that resist degradation. The two most studied — PFOA (perfluorooctanoic acid) and PFOS (perfluorooctane sulfonic acid) — have been phased out of U.S. manufacturing but persist widely in the environment.

Why Do People Care?

PFAS contamination affects an estimated 200 million Americans' drinking water. Because they accumulate in the body over time, even low-level chronic exposure is associated with serious health outcomes including cancer, immune system disruption, and hormonal effects.

People near military bases (which used PFAS-containing firefighting foam), industrial sites, and communities that have received contaminated biosolid fertilizer face the highest exposure. Infants, pregnant women, and people with compromised immune systems are most vulnerable.

Known Health Effects

Increased risk of kidney and testicular cancer

Thyroid disease and hormonal disruption

Immune system suppression — reduced vaccine effectiveness

High cholesterol and cardiovascular effects

Developmental delays and low birth weight in infants

Liver damage at high exposure levels

Common Sources

Industrial manufacturing facilities (chemical plants, refineries)

Military bases and airports using AFFF firefighting foam

Non-stick cookware and food packaging manufacturing

Stain-resistant fabric and carpet treatments

Landfill leachate from consumer product disposal

Biosolid (sewage sludge) land application on farmland

Regulatory Limit

EPA Maximum Contaminant Level (MCL)

4 ppt

In April 2024, the EPA finalized the first federal Maximum Contaminant Levels (MCLs) for PFAS: 4 parts per trillion (ppt) each for PFOA and PFOS individually; 10 ppt for PFNA, PFHxS, and HFPO-DA; and a Hazard Index for mixtures. Water systems must comply by 2029. The MCL goal (MCLG) for PFOA and PFOS is zero.

How to Test for It

PFAS are detected through EPA Method 533 or Method 537.1 laboratory analysis. The EPA requires public water systems serving 10,000+ people to test for PFAS under the Fifth Unregulated Contaminant Monitoring Rule (UCMR 5). Check your annual Consumer Confidence Report (CCR) or contact your utility for test results.

Effective Treatment Options

These treatment methods have demonstrated effectiveness for PFAS.

Reverse Osmosis

Reverse osmosis (RO) is the most comprehensive point-of-use water treatment technology available for residential use. It removes 90–99% of dissolved contaminants including PFAS, lead, arsenic, nitrates, and disinfection byproducts by forcing water through a semi-permeable membrane with pores of approximately 0.0001 microns.

PFAS / PFOA / PFOS — 90–99% removalLead — 95–99% removal

Activated Carbon

Activated carbon is the most widely used residential water treatment technology. It removes chlorine, taste and odor compounds, disinfection byproducts, many volatile organic compounds (VOCs), and — with NSF/ANSI 53 certification — lead and some PFAS. It is available as pitcher filters, under-sink units, and whole-house systems.

Chlorine and chloramine — virtually complete removalTaste and odor compounds — highly effective

Frequently Asked Questions

Reverse Osmosis Filtration

Removes: PFAS

Activated Carbon Filtration

Removes: PFAS

Data Sources & Provenance

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

EPA Drinking Water Contaminant InformationView source

ATSDR ToxFAQs / Toxicological ProfilesView source

EPA SDWIS — violation and detection dataView source

Last updated: 2025-01-15

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