Is there PFAS in Fairfax County Water Authority water?
Yes. EPA's final UCMR 5 results show Fairfax County Water Authority averaged 4.6 ppt of PFOA at its worst sampling point, 1.1 times the EPA limit of 4 ppt.
Fairfax County Water Authority
Serves 1.1 million people · 24 PFOA samples from 6 sampling points · Mar 2024 to Feb 2025
Average above an EPA limit
PFOA Perfluorooctanoic acid
4.6 ppt avg · max 7.4
PFOS Perfluorooctanesulfonic acid
2.6 ppt avg · max 5.7
Hazard index GenX, PFBS, PFNA, PFHxS combined
not detected
Also detected, no federal limit: PFPeA, PFBA, PFHxA, 6:2 FTS, PFBS, PFHpA.
Fairfax County Water Authority is a public water system drawing on surface water, based in Herndon, Virginia, serving about 1.1 million people, including Centreville, Clifton, Chantilly, Sterling, Herndon, Reston. Under EPA's Fifth Unregulated Contaminant Monitoring Rule it was tested for 29 PFAS and lithium 24 times across 6 sampling points between Mar 2024 and Feb 2025.
Every PFAS detected
Not detected: 8:2 FTS, PFMPA, PFMBA, PFEESA, NFDHA, PFTrDA, PFHpS, PFTA, 4:2 FTS, PFDoA, NEtFOSAA, PFPeS, PFDA, NMeFOSAA, PFHxS, PFNA, PFUnA, 11Cl-PF3OUdS, 9Cl-PF3ONS, ADONA, HFPO-DA.
Lithium, tested in the same program: not detected.
What the EPA limits mean here
In April 2024 EPA set enforceable limits of 4 ppt for PFOA and PFOS, 10 ppt each for PFHxS, PFNA and GenX, and a hazard index of 1 for mixtures. Utilities were given until 2029 to comply. In May 2026 EPA proposed keeping only the PFOA and PFOS limits and moving that deadline to 2031. Until that proposal is final, the 2024 limits stand.
Compliance is judged on a running annual average at each entry point, so we show the average at this system's worst sampling point next to its single highest result. UCMR 5 results do not by themselves put a utility in or out of compliance.
What you can do at home
Two routes work for PFAS. For drinking and cooking water only, a reverse osmosis system certified to NSF/ANSI 58 with a PFOA/PFOS reduction claim is the cheapest proven option. To treat every tap and shower, a whole-house carbon system with enough contact time works, but check that the maker has PFAS test data, not just a marketing claim. See the best filters for PFAS and how PFAS removal works.
Other systems in Virginia
All 171 tested systems in Virginia
ZIP codes served
20120 20121 20124 20151 20153 20164 20170 20171 20190 20191 20192 20194 20195 22003 22015 22027 22030 22031 22032 22033 22035 22039 22041 22042 22043 22044 22046 22060 22066 22079 22101 22102 22122 22124 22150 22151 22152 22153 22180 22181 22182 22204 22206 22302 22303 22304 22306 22307 22308 22309 22310 22311 22312 22315
As reported by the utility to EPA. Neighbouring ZIPs are often split between systems; your water bill names yours.
Cite this page
Well & Tap. "PFAS in Fairfax County Water Authority water: EPA UCMR 5 results." Data: U.S. EPA Fifth Unregulated Contaminant Monitoring Rule, final release August 2026, PWSID VA6059501. https://wellandtap.com/pfas/virginia/fairfax-county-water-authority/
About this data
Source: U.S. EPA, UCMR 5 occurrence data, final release August 2026 (PWSID VA6059501). Population: EPA SDWIS. Averages count results below the reporting level as zero, the same convention EPA uses for running annual averages. Full method.
