Contaminants
Do Water Filters Remove PFAS? What the Research Shows
PFAS are a large family of long-lasting synthetic chemicals, often called “forever chemicals.” Some home filters reduce them very well. Others are hit or miss. The type of filter matters more than the brand.
Key takeaways
- In a study of 76 home filters, under-sink reverse osmosis and two-stage filters removed 94% or more of the PFAS measured.
- Activated carbon filters (pitchers, faucet, fridge) removed 73% on average, but results ranged from complete removal to none.
- Whole-house carbon systems are not a good PFAS fix. Levels rose after filtration in 4 of 6 tested.
- The EPA set enforceable limits of 4 parts per trillion for PFOA and PFOS in 2024. A 2026 proposal would keep those limits but give utilities until 2031.
- Buy a filter certified to NSF/ANSI 53 or 58 for PFOA/PFOS reduction, and replace cartridges on schedule.
What the EPA requires right now
In April 2024 the EPA finalized the first national drinking water limits for PFAS. The rule set maximum contaminant levels of 4.0 ppt each for PFOA and PFOS, 10 ppt each for PFHxS, PFNA and HFPO-DA (GenX), and a Hazard Index limit for mixtures. The health goal for PFOA and PFOS is zero.[1]
Under that rule, water systems must finish initial monitoring by 2027, and the limits become enforceable in 2029.[1] Then the picture shifted:
- In May 2025 the EPA announced it would keep the PFOA and PFOS limits but extend their deadline and rescind the other four.[2]
- On May 18, 2026 it formally proposed both changes: PFOA and PFOS compliance moves to 2031, and the limits for PFHxS, PFNA, GenX and the Hazard Index would be withdrawn.[1][2]
- As of our last review, those proposals are not final, and the 2024 rule is still being challenged in federal court.[2]
For you, the practical upshot is simple. Your utility may not be required to meet the PFAS limits for several more years, so a home filter is a reasonable step if your water report shows PFAS.
Parts per trillion is tiny. One part per trillion is roughly one drop of water spread across 20 Olympic-size swimming pools. Most home test kits can't measure levels that low. Use your utility's results or a certified lab.
The best evidence on home filters
The most-cited real-world study comes from Duke University and North Carolina State University, published in Environmental Science & Technology Letters in 2020. Researchers tested 76 point-of-use filters and 13 whole-house systems in homes across North Carolina, including areas with high PFAS levels.[3][4]
| Filter type | PFAS removal in the study |
|---|---|
| Under-sink reverse osmosis | 94% or more, near-complete for the PFAS tested |
| Two-stage under-sink filters | 94% or more (only a few units tested) |
| Activated carbon: pitcher, faucet, fridge, countertop | 73% on average, ranging from complete to none |
| Whole-house activated carbon | Highly variable. PFAS rose after filtration in 4 of 6 systems |
The researchers found no clear link between carbon filter performance and brand, filter age or source-water PFAS levels.[4] They also warned that filters that aren't maintained can make PFAS levels worse, and that home filters are a stopgap while PFAS is controlled at the source.[4]
Why reverse osmosis does better
Carbon removes PFAS by adsorption, and it works best on long-chain PFAS like PFOA and PFOS. Short-chain compounds slip through more easily, and once the carbon's sites fill up, removal drops. A reverse osmosis membrane physically blocks most dissolved molecules, so it handles both long- and short-chain PFAS more reliably.[5]
How to choose a filter for PFAS
- Confirm the problem. Check your utility's water quality report or state PFAS sampling results. See our guide to reading your water report.
- Prefer reverse osmosis or a multi-stage under-sink filter if PFAS levels are well above 4 ppt.
- Check the certification. Look for NSF/ANSI 53 or 58 with a PFOA/PFOS reduction claim in the public listing. See how to check.
- Replace cartridges on time. Certification is tested up to the rated capacity. An overdue filter can release what it captured.
- Treat the kitchen tap, not the whole house. Drinking and cooking water are the main exposure routes. The EPA publishes a fact sheet on reducing PFAS with a home filter.[1]
Frequently asked questions
Does a Brita filter remove PFAS?
It depends on the cartridge. Brita sells several cartridges for the same pitchers, and their certified claims differ. Look up the exact cartridge model in NSF's listing and check for a PFOA/PFOS reduction claim. In the Duke and NC State study, carbon pitcher filters as a group were inconsistent.
Does boiling water remove PFAS?
No. Boiling does not destroy PFAS, and as water evaporates the concentration can rise slightly.
Is bottled water free of PFAS?
Not necessarily. Bottled water is regulated by the FDA, not the EPA, and PFAS have been detected in some bottled waters. A certified home filter is usually cheaper and easier to verify.
Sources
- US EPA, “Per- and Polyfluoroalkyl Substances (PFAS)” drinking water regulation page, updated May 18, 2026. epa.gov
- Harvard Law School Environmental & Energy Law Program, “PFAS in Drinking Water” regulatory tracker, updated September 2026. eelp.law.harvard.edu
- Herkert NJ, Merrill J, Peters C, et al. “Assessing the Effectiveness of Point-of-Use Residential Drinking Water Filters for Perfluoroalkyl Substances (PFASs).” Environ. Sci. Technol. Lett. 2020;7(3):178–184. doi.org
- Water Online, “Not All In-Home Drinking Water Filters Completely Remove Toxic PFAS,” February 5, 2020 (Duke University release). wateronline.com
- Duke University Superfund Research Center, “PFAS Factsheet on Filters”. sites.nicholas.duke.edu
This guide is general information, not medical advice. Rules and certifications change. We last checked these sources on October 7, 2026. Found an error? Tell us and we will correct it.