PFAS in Drinking Water: What It Is, Where It’s Found, and How to Remove It

LAST UPDATED: April 2026

On April 10, 2024, the EPA finalized the first-ever National Primary Drinking Water Regulations (NPDWRs) for PFAS, establishing an enforceable maximum contaminant level (MCL) of 4 parts per trillion (ppt) for PFOA and PFOS. This regulatory action reflects decades of toxicological research documenting PFAS accumulation in human tissue and association with cancer, immune suppression, and developmental harm. An estimated 200 million Americans have detectable PFAS in their drinking water, and according to EPA UCMR5 data and corroborating EWG tap water database results, millions currently exceed the new federal threshold.

For context on US tap water safety generally, see Is Tap Water Safe to Drink in the US?.

KEY TAKEAWAYS:

PFAS are synthetic “forever chemicals” linked to cancer, immune disruption, and developmental harm.
The EPA’s April 2024 rule set an enforceable limit of 4 ppt for PFOA and PFOS.
An estimated 200 million Americans drink water with detectable PFAS levels. Many exceed the new EPA limits.
NSF 53 for PFAS (P473 incorporated into NSF 53 in 2019) is the certification that verifies PFAS removal in water filters. NSF 42 alone does not. A filter “tested to NSF standards” is not the same as one holding NSF 53 certification for PFAS.
No filter removes all PFAS. Certified filters reduce PFOA and PFOS specifically. The broader PFAS family includes thousands of compounds.

What Is PFAS and Why Is It in Your Drinking Water?

PFAS stands for per- and polyfluoroalkyl substances—a family of more than 12,000 synthetic chemicals manufactured since the 1940s for industrial and consumer applications. The carbon-fluorine bond that confers their utility (nonstick properties in cookware, foam stability in firefighting formulations, grease resistance in food packaging) is also what makes them persistent. This bond resists hydrolysis (the chemical process by which water breaks molecular bonds) and does not degrade under normal environmental conditions—in water, soil, sediment, or biological tissue.

PFAS contamination reaches drinking water through multiple pathways:

Industrial discharge: Chemical manufacturing plants, fluoropolymer processing facilities, and metal finishing operations (chrome plating, steel treatment) release PFAS directly into groundwater and surface water.
Firefighting foam (AFFF): Aqueous film-forming foam, a firefighting agent deployed at military bases, civilian airports, and firefighting training sites, is the single largest identified source of PFAS groundwater contamination in the US. The Department of Defense has documented PFAS contamination at more than 700 military installations.
Landfill leachate: Consumer products containing PFAS (food packaging, textiles, cookware) end up in landfills. As water percolates through landfill waste, PFAS leaches into groundwater over years and decades.
Land application of biosolids: Wastewater treatment plants produce biosolids (the solid residue remaining after pathogen reduction treatment of sewage). When biosolids are applied to agricultural land as fertilizer, PFAS persists and migrates downward into groundwater.

Once PFAS enters a water source—whether groundwater, surface water, or both—it moves through the hydrologic system to municipal water intakes. Groundwater-fed public water systems and private wells face direct exposure. Surface water systems drawing from rivers and lakes downstream of industrial or military sites become contaminated secondarily.

Where Is PFAS Most Commonly Found?

PFAS contamination is widespread but unevenly distributed. The EWG Tap Water Database maps detections by water system across the US. High-risk areas:

Near military bases (over 700 military sites have documented PFAS contamination)
Near airports with active fire training operations
Adjacent to chemical manufacturing facilities, especially in the Cape Fear River basin in North Carolina and parts of the Midwest
San Fernando Valley groundwater in Los Angeles, with some of the highest documented PFAS levels in California — see our Los Angeles water quality report

To check your own water system, search your utility name in the EWG Tap Water Database and read your municipality’s Consumer Confidence Report (CCR). How to test your water at home

Health Effects of PFAS in Drinking Water

PFAS at the parts-per-trillion concentrations typical of tap water does not produce acute toxicity. The hazard stems from bioaccumulation (the process by which PFAS concentrates in tissue over time). PFAS binds to proteins in blood and accumulates in the liver, kidney, and other organs. Tissue concentrations reach levels substantially higher than water concentration because the compounds are neither metabolized nor excreted readily.

Here’s what the data actually shows. Health effects documented in peer-reviewed research and cited by the EPA:

Cancer: Higher kidney and testicular cancer incidence in occupationally exposed workers and populations near contamination sites.
Immune suppression: Reduced vaccine response antibody titers in children with elevated serum PFAS, suggesting impaired adaptive immune function.
Thyroid disruption: PFAS alters thyroid hormone binding and metabolism, with associations to hypothyroidism and reduced free thyroxine in exposed populations.
Reproductive effects: Pregnant women with elevated serum PFAS show increased risk for pregnancy-induced hypertension and preeclampsia. Offspring show associations with reduced birth weight and altered metabolic markers.
Lipid metabolism: Consistent association between PFAS serum concentration and elevated LDL cholesterol across multiple occupational and community cohort studies, as detailed in the ATSDR Toxicological Profile for PFAS.

The EPA’s 4 ppt MCL reflects a critical regulatory principle: the agency concluded there is no demonstrable threshold below which PFOA and PFOS cause no harm. The 4 ppt represents the practical quantitation limit (the lowest concentration laboratory methods can reliably measure), not a “safe level.” Below this limit, risk cannot be quantified. Above it, established health associations exist.

The 2024 EPA MCL Rule: What It Means for Homeowners

The EPA’s April 2024 final rule established enforceable MCLs for six PFAS compounds:

PFAS Compound	EPA MCL (April 2024)
PFOA	4 ppt (individual)
PFOS	4 ppt (individual)
PFNA	10 ppt
PFHxS	10 ppt
HFPO-DA (GenX)	10 ppt
PFBS	Hazard Index 1 (mixture)

The compliance timeline has two phases: utilities must complete initial monitoring and public reporting by 2027. The EPA extended the treatment compliance deadline from the original 2029 target to 2031, citing supply chain constraints for treatment equipment and ongoing litigation. As of 2026, water systems exceeding these new MCLs are in the monitoring phase but not yet legally required to have treatment in place. For households in affected areas seeking protection now, point-of-use filtration (at the tap) is the only available intervention.

According to EPA UCMR5 data corroborated by EWG database results, more than 70,000 public water systems will require testing under the new rule. Early monitoring data shows a significant number already exceed the 4 ppt PFOA and PFOS threshold.

Which Water Filters Remove PFAS?

This is where confusion and misleading marketing run rampant. Three home filtration approaches actually work for PFAS, each with trade-offs.

NSF 53 (PFAS): The Only Certification That Matters for PFAS

NSF 53 for PFAS is the American National Standard for PFAS removal verification in water filters. (Previously designated as NSF P473, the PFAS testing protocol was officially incorporated into NSF/ANSI 53 in 2019.) A filter bearing this certification has undergone independent third-party laboratory testing (by NSF International or equivalent accredited testing body) for PFOA and PFOS reduction. This is the only certification standard that addresses PFAS.

The distinction matters. NSF/ANSI 42 addresses chlorine taste and odor removal. NSF/ANSI 53 now encompasses both health-effect contaminants like lead and PFAS reduction protocols. A manufacturer’s claim that a filter is “tested to NSF standards” without explicitly holding NSF 53 certification for PFAS does not constitute proof of PFAS reduction. You can verify certifications directly in the NSF certified product database.

One more critical point: NSF 53 certification for PFAS specifically covers PFOA and PFOS. The PFAS family comprises more than 12,000 compounds. No residential filter removes all PFAS. Certified products reduce the two compounds driving regulatory action and the ones with the most extensive toxicological documentation. Reduction of other PFAS compounds cannot be claimed without separate third-party verification.

Pitcher Filters: Verified Options Are Limited

The vast majority of pitcher filters perform no reduction of PFAS. A small number hold NSF 53 (PFAS) certification:

ZeroWater 10-Cup

One of the few pitchers with NSF 53 certification for PFAS. The system uses a 5-stage ion exchange resin that removes ionic PFAS compounds including PFOA and PFOS. Check on Amazon

Trade-offs: Filter lifespan is brief—approximately 15–25 gallons depending on your water’s total dissolved solids (TDS)—which creates high replacement frequency and cost accumulation. The ion exchange resin produces a slightly acidic pH shift as it nears saturation, which some users perceive as acidic taste in the final weeks of filter life.

Epic Pure Pitcher

Also holds NSF 53 certification for PFAS with independently verified third-party lab testing data demonstrating PFOA and PFOS reduction.

Trade-offs: Filtration rate is slower than gravity-fed pitchers using activated carbon (such as Brita). Per-filter cost is higher than pitchers lacking PFAS certification.

Standard Brita pitchers remove zero PFAS. Brita Longlast+ models have shown PFAS reduction in Brita’s internal testing, but carry no NSF 53 (PFAS) certification—no independent laboratory has verified these results. See Do Brita Filters Remove PFAS? for detailed analysis.

Additional pitcher options appear in our best water filter pitchers for 2026 guide.

Under Sink Filters: Higher PFOA and PFOS Reduction Than Pitchers

Under-sink systems with NSF 53 (PFAS) certification perform more reliable PFAS reduction than pitchers, with substantially higher flow rates and lower cost per unit volume of filtered water.

Aquasana AQ-5200

Holds NSF/ANSI 42, 53, and 401 certifications (including NSF 53 for PFAS, formerly P473)—all verifiable in the NSF certified product database. This dual-stage design offers mid-range cost for households with documented PFAS in drinking water. Check on Amazon

Trade-offs: Requires under-sink installation with a dedicated tap, which eliminates this option for many renters. Replacement filter cost approximates $60 per six-month replacement cycle. Flow rate diminishes progressively as filter approaches saturation. Timeline details appear in how often to change your water filter.

Crystal Quest manufactures NSF-certified under-sink and whole-house systems with PFAS reduction capability. Buy from Crystal Quest

Trade-offs: Initial system cost exceeds the Aquasana. Customer service responsiveness receives mixed reviews in published assessments.

For comprehensive comparison: best under sink water filters 2026.

Reverse Osmosis: Highest PFAS Reduction

Reverse osmosis (RO) systems demonstrate the highest documented PFOA and PFOS reduction—published data shows 90%+ removal in laboratory testing. The semi-permeable membrane (a synthetic polymer with pore size of approximately 0.0001 microns) physically excludes PFAS molecules from permeate (product water). RO systems carry higher cost ($200–$600), generate reject water, and substantially reduce flow rate. If serum PFAS levels or source water PFAS concentration is documented as high, RO remains the most comprehensive option. For municipal water with moderate PFAS, NSF 53-certified (PFAS) under-sink filtration typically achieves the treatment objective.

Trade-offs: Rejects 2–4 gallons of water for each gallon of treated water produced. This impacts municipal water bills and is problematic in water-constrained regions. RO systems remove beneficial minerals (calcium, magnesium) along with contaminants, producing slightly demineralized product water. Filling large containers becomes time-consuming due to reduced flow rate.

What No Filter Removes

No residential filtration system removes all PFAS compounds. NSF 53 (PFAS) certification addresses PFOA and PFOS—the compounds with the most extensive human health data and the ones specified in the EPA’s April 2024 regulation. The PFAS universe contains more than 12,000 distinct compounds. Analytical methods to quantify most PFAS compounds remain under development, and no established health guidance exists for the vast majority. No commercially available filter can support claims of complete PFAS removal.

For whole-house filtration options, see best whole house water filters 2026.

How to Find Out If Your Water Has PFAS

Step 1—Check the EWG Tap Water Database. Navigate to ewg.org/tapwater and enter your city or zip code. The database aggregates utility testing results and reports detection status and quantified PFAS levels by water system.

Step 2—Review your Consumer Confidence Report (CCR). Your municipal utility publishes this annually and makes it available on their website or by request. Under the EPA’s 2024 rule, utilities must test for and report detection of six specific PFAS compounds. Search “[your city] water quality report 2026” or visit your utility website directly. For municipal examples, see our analysis of the Chicago water quality report and Los Angeles water quality.

Step 3—Request laboratory analysis if you use private well water. The EWG database and CCRs cover municipal water systems only. Private wells receive no regulatory testing. Wells located near military installations, civilian airports, or industrial sites face elevated PFAS contamination risk due to source proximity. A mail-in laboratory panel from Tap Score that includes comprehensive PFAS analysis runs $350–$450 and provides quantified concentration data for your specific well water.

Full guide: How to Test Your Water at Home

Frequently Asked Questions

Is PFAS in my drinking water dangerous?

At the parts-per-trillion concentrations found in most US municipal water, PFAS does not produce acute toxicity. The hazard is accumulative—PFAS persists and concentrates in tissue over time, reaching blood and organ levels substantially above water concentration. The EPA’s 2024 regulation assumes no safe threshold (no-observed-adverse-effect level, or NOAEL) exists for PFOA and PFOS. The 4 ppt MCL was set at the practical quantitation limit, meaning below this level, current methods cannot measure exposure. If PFAS is detected in your water at any measurable level, point-of-use filtration represents a reasonable risk mitigation approach, particularly for pregnant women, infants, and young children, whose developmental windows create windows of heightened susceptibility.

What did the EPA’s 2024 PFAS rule actually change?

Before April 2024, no enforceable federal MCLs existed for PFAS. The EPA issued only a non-enforceable health advisory of 70 ppt (combined PFOA and PFOS). The 2024 final rule established binding MCLs: 4 ppt for PFOA and PFOS individually, 10 ppt for PFNA (perfluorononanoic acid) and PFHxS (perfluorohexanesulfonic acid), and a hazard index (mixture rule) for PFBS and HFPO-DA (GenX). Compliance deadline is 2029. Systems currently exceeding the new thresholds have not yet faced legal enforcement to address noncompliance.

Does boiling water remove PFAS?

No. Boiling water concentrates PFAS. As water evaporates during heating, dissolved compounds remain behind, producing higher PFAS concentration in the remaining liquid. Boiling effectively removes microbial pathogens and some volatile organic compounds. It has no effect on persistent synthetic chemicals like PFOA and PFOS.

Pitcher filter versus under-sink filter for PFAS—which performs better?

Both ZeroWater and Epic Pure pitchers hold NSF 53 (PFAS) certification and demonstrate measurable PFOA and PFOS reduction. Under-sink systems including the Aquasana AQ-5200 also carry NSF 53 (PFAS) certification and typically achieve lower cost per liter of filtered water due to longer cartridge lifespan. For single-person or two-person households filtering drinking water only, pitcher systems represent adequate coverage. For larger households or simultaneous filtration of drinking and cooking water, under-sink systems prove more practical. See best under sink water filters 2026

What is the actual difference between NSF 53 (PFAS) certification versus “NSF tested”?

NSF 53 certification for PFAS (formerly NSF P473) means an independent third-party laboratory (NSF International or equivalent ANSI-accredited testing body) has verified filter performance for PFOA and PFOS reduction through controlled testing and ongoing compliance verification. This certification status is public and verifiable. “Tested to NSF standards” is marketing language that does not require third-party verification—the manufacturer may have conducted testing using NSF protocol, but no external laboratory confirmed the results. Only filters listed in the NSF certified product database carry genuine third-party verification.

Sources

EPA: National Primary Drinking Water Regulations for PFAS — Final Rule, April 2024
EWG Tap Water Database
NSF International — NSF 53 (PFAS) Certification Standard (formerly P473)
EPA PFAS Health Advisories and Maximum Contaminant Level technical documents
Agency for Toxic Substances and Disease Registry (ATSDR): PFAS Toxicological Profile
Department of Defense PFAS Information
Tap Score: PFAS in drinking water testing resources
Environmental Science & Technology: peer-reviewed PFAS bioaccumulation research

Filterd Water Guide

PFAS in Drinking Water: What It Is and How to Remove It