PFAS in Drinking Water

Last updated: February 2026

What Are PFAS? The Basics

PFAS stands for per- and polyfluoroalkyl substances — a broad class of over 12,000 synthetic chemicals that have been manufactured and used in consumer and industrial products since the 1940s. The defining characteristic: they're built around an exceptionally strong carbon-fluorine bond that makes them almost indestructible.

That stability is precisely what made them so useful. PFAS repel oil, grease, and water, making them ideal for:

• Non-stick cookware (Teflon)
• Waterproof clothing and gear
• Food packaging (pizza boxes, popcorn bags, fast food wrappers)
• Firefighting foam (AFFF) used at airports and military bases
• Stain-resistant carpets and upholstery
• Semiconductor manufacturing

The same stability that makes PFAS useful also makes them environmental and biological nightmares. They accumulate in soil, groundwater, and the human body for decades. Blood serum tests show detectable PFAS in 97% of Americans — the result of decades of near-universal exposure through water, food, dust, and consumer products.

How Common Is PFAS Contamination in Drinking Water?

PFAS contamination in U.S. drinking water is widespread and under-measured simultaneously. Here's the state of knowledge as of early 2026:

• The 2023 USGS study tested 716 tap water locations nationwide and found PFAS detectable in 45%, with higher rates near urban areas, military facilities, and industrial zones.
• EWG's analysis of utility data estimates that 200+ million Americans may be consuming tap water contaminated with PFAS at levels above their health guidelines.
• More than 2,800 locations across the U.S. are known to have PFAS contamination in surrounding water sources, per the Environmental Defense Fund — and that number grows as testing expands.
• Communities near military installations using AFFF firefighting foam face some of the highest documented PFAS levels. The Department of Defense has identified contamination at over 700 bases.

A critical caveat: most PFAS contamination data comes from utilities that have only recently begun testing. Thousands of water systems haven't yet reported comprehensive PFAS data, meaning national estimates are almost certainly undercounts.

Where Does PFAS Come From?

PFAS enters drinking water through several routes:

Industrial Discharge

Manufacturing facilities that produce or use PFAS chemicals — including chemical plants, semiconductor fabs, and textile mills — have historically discharged PFAS into waterways and wastewater systems. These compounds resist conventional water treatment and persist in source water for decades.

Military Firefighting Foam (AFFF)

Aqueous film-forming foam (AFFF), used at military bases and civilian airports for firefighting training and emergencies, contains extremely high concentrations of PFAS. Decades of use have contaminated groundwater at and around hundreds of military installations. This is the primary source of some of the highest PFAS concentrations found in U.S. water systems.

Landfill Leachate

Products containing PFAS — Teflon pans, waterproof gear, food packaging — end up in landfills. Over time, PFAS leach into surrounding soil and groundwater. Virtually every landfill in the U.S. that accepted modern consumer goods is a potential PFAS source.

Agricultural Application of Biosolids

Sewage sludge (biosolids) from wastewater treatment plants has been widely applied to farmland as fertilizer for decades. Much of this sludge contains PFAS from household and industrial wastewater. PFAS applied to fields can leach into groundwater or run off into nearby surface water, contaminating wells and downstream public water systems.

Urban Runoff

PFAS-containing products used in buildings, roads, and consumer goods eventually wash into storm drains and waterways through rain and runoff. This is a diffuse but significant source in highly urban areas.

Health Effects of PFAS Exposure

The health research on PFAS is extensive and continues to grow. The following effects have the strongest scientific evidence:

Cancer

PFOA (C8) is classified as a possible human carcinogen by the International Agency for Research on Cancer (IARC) and a "likely carcinogen" by the EPA. PFOS and other compounds are under review. Studies of highly exposed communities and workers link PFAS to:

• Kidney cancer (strongest association)
• Testicular cancer
• Bladder cancer
• Non-Hodgkin lymphoma
• Breast cancer (emerging evidence)

Thyroid Disruption

PFAS interfere with thyroid hormone production and function. Multiple studies link PFAS exposure to hypothyroidism, thyroid disease, and altered thyroid hormone levels in both adults and children. The thyroid effects are particularly concerning for pregnant women, as thyroid hormones are essential for fetal brain development.

Immune Suppression

Some of the most concerning recent evidence shows that PFAS reduce vaccine effectiveness and overall immune function. A 2020 study published in JAMA Pediatrics found that children with higher PFAS blood levels had significantly lower antibody responses to vaccines. This finding gained attention during the COVID-19 pandemic as researchers studied why some communities had poorer vaccine outcomes.

Reproductive and Developmental Effects

• Reduced fertility in both men and women
• Preeclampsia and pregnancy-induced hypertension
• Reduced birth weight and fetal growth restriction
• Altered puberty timing in children
• Breastfed infants may receive PFAS through breast milk from mothers with high body burdens

Liver Damage

PFAS accumulate in liver tissue and can cause elevated liver enzymes, hepatomegaly (enlarged liver), and in animal studies, liver tumors at high doses. Non-alcoholic fatty liver disease risk appears elevated in high-exposure populations.

Cardiovascular Effects

Emerging evidence links PFAS to elevated cholesterol, hypertension, and metabolic syndrome. The cholesterol effects appear particularly dose-dependent and have been replicated across multiple study populations.

Children Are Especially Vulnerable

Children face heightened risks from PFAS exposure because they consume more water relative to body weight, their developing organs are more sensitive to endocrine disruption, PFAS can cross the placental barrier during fetal development, and they're exposed earlier in life, increasing cumulative lifetime exposure.

The 2024 EPA PFAS Limits: What Changed

In April 2024, the EPA finalized the first-ever enforceable national limits for PFAS in drinking water. This was a major milestone — for decades, PFAS had no federal drinking water standard, leaving utilities with no legal obligation to test or treat for it.

Key facts about the new rule:

• Utilities have until 2029 to comply — meaning many are still operating above these limits right now.
• Even the new EPA limits are thousands of times higher than EWG health guidelines, which are based on stricter 1-in-a-million cancer risk calculations.
• The rule covers only six PFAS compounds out of 12,000+. Many PFAS in widespread use have no limit at all.
• An estimated 6,600 to 12,000 water systems may need to add treatment to comply by 2029.

How to Test Your Water for PFAS

PFAS have no taste, odor, or color. You cannot detect them without testing. Here are your options:

Option 1: Check the EWG Database (Free)

Look up your utility at the EWG Tap Water Database. If your utility has reported PFAS testing data, you'll see it here. Limitation: many utilities haven't reported PFAS data yet, so a blank result doesn't mean your water is PFAS-free.

Option 2: Contact Your Utility

Call or email your water utility and ask specifically about PFAS testing results. Under the 2024 EPA rule, large utilities are required to test and report — though compliance timelines extend to 2025-2026 for some systems.

Option 3: Home PFAS Test Kit (Most Accurate for Your Tap)

A mail-in test kit provides lab-certified analysis of your actual tap water. Look for kits that test for the EPA's six regulated PFAS compounds at minimum, ideally more.

Which Water Filters Actually Remove PFAS

This is where many people get misled by marketing claims. Here's what the NSF/ANSI testing data actually shows:

✅ Reverse Osmosis (RO) — Most Effective

Reverse osmosis removes 94–99% of PFAS from drinking water. The semi-permeable RO membrane physically blocks PFAS molecules. NSF/ANSI 58 certified RO systems have been independently verified for PFAS removal. This is the gold standard for PFAS removal in home water treatment.

✅ Activated Carbon (NSF 53/58 Certified) — Effective

High-quality granular activated carbon (GAC) and solid block activated carbon filters can remove significant amounts of PFAS, particularly longer-chain PFAS like PFOA and PFOS. Effectiveness varies by filter quality, contact time, and which PFAS compounds are present. Look specifically for NSF/ANSI P473 certification, which is the PFAS-specific standard for drinking water treatment.

⚠️ Standard Pitcher Filters (Brita, Zero, etc.) — Limited

Basic pitcher filters use limited amounts of activated carbon optimized for taste and odor improvement. They do not reliably remove PFAS. The exception is certain upgraded filter cartridges marketed specifically for PFAS — check for NSF P473 certification on the specific cartridge, not just the pitcher brand.

❌ Boiling Water — Does Not Work

Boiling concentrates PFAS by removing water through evaporation. Never boil water as a PFAS removal strategy — it makes the situation worse.

❌ Standard Sediment Filters — Does Not Work

Sediment, ceramic, and UV filters do not remove chemical contaminants like PFAS.

Our Top PFAS Filter Recommendations

High-Risk Areas for PFAS in Drinking Water

While PFAS contamination is widespread nationally, certain areas face elevated risk:

Near Military Bases and Airports

Military installations that used AFFF firefighting foam, and airports required to stockpile AFFF for aircraft emergencies, are among the highest-risk locations for PFAS contamination. The Department of Defense has identified over 700 contaminated sites. If you live within 10 miles of a military base or major airport, PFAS testing is strongly recommended.

Near Chemical Manufacturing

3M, DuPont, and Chemours manufacturing sites have been associated with major PFAS contamination events. Communities in North Carolina (Cape Fear River), Alabama, and New Jersey near PFAS manufacturing facilities have documented some of the highest residential PFAS exposures in the country.

Agricultural Areas with Biosolid Application

Farmers in Maine, Michigan, and other states have found PFAS contaminating well water after biosolids (sewage sludge) were applied to fields. If you have a private well in an agricultural area, PFAS testing is important.

Industrial Corridors

Manufacturing and industrial zones with textile mills, semiconductor fabs, and chemical processing plants are common PFAS hotspots due to historical discharge practices.

Frequently Asked Questions