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Is there PFAS in Cliffdale West water?

Yes. EPA's final UCMR 5 results show Cliffdale West averaged 17.4 ppt of PFOS at its worst sampling point, 4.3 times the EPA limit of 4 ppt.

Cliffdale West Serves 15,220 people · 54 PFOA samples from 27 sampling points · Feb 2025 to Sep 2025 Average above an EPA limit
PFOA Perfluorooctanoic acid 16.1 ppt avg · max 16.3
EPA 4
PFOS Perfluorooctanesulfonic acid 17.4 ppt avg · max 19.5
EPA 4
PFHxS Perfluorohexanesulfonic acid 12.4 ppt avg · max 12.5
EPA 10
Hazard index GenX, PFBS, PFNA, PFHxS combined 1.2 avg · max 1.3
EPA 1

Also detected, no federal limit: PFBS, PFHxA, PFPeA, PFHpA.

Averages are for the worst sampling point, with non-detects counted as zero. Source: EPA UCMR 5.

Cliffdale West is a public water system drawing on groundwater, based in Cary, North Carolina, serving about 15,220 people. Under EPA's Fifth Unregulated Contaminant Monitoring Rule it was tested for 29 PFAS and lithium 54 times across 27 sampling points between Feb 2025 and Sep 2025.

Every PFAS detected

PFAS Detected Highest Worst point avg EPA limit
PFOS
Perfluorooctanesulfonic acid		 25 of 54 19.5 ppt 17.4 ppt 4 ppt
PFOA
Perfluorooctanoic acid		 25 of 54 16.3 ppt 16.1 ppt 4 ppt
PFHxS
Perfluorohexanesulfonic acid		 36 of 54 12.5 ppt 12.4 ppt 10 ppt
PFBS
Perfluorobutanesulfonic acid		 31 of 54 10.8 ppt 10.6 ppt none
PFHxA
Perfluorohexanoic acid		 25 of 54 10.2 ppt 10.0 ppt none
PFPeA
Perfluoropentanoic acid		 28 of 54 8.7 ppt 8.6 ppt none
PFHpA
Perfluoroheptanoic acid		 9 of 54 4.5 ppt 4.4 ppt none

Not detected: HFPO-DA, PFBA, 6:2 FTS, 4:2 FTS, 8:2 FTS, PFEESA, PFMBA, ADONA, PFNA, PFPeS, NFDHA, PFMPA, 9Cl-PF3ONS, 11Cl-PF3OUdS, PFUnA, PFDoA, PFDA, PFHpS, NEtFOSAA, PFTrDA, PFTA, NMeFOSAA.

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 North Carolina

All 291 tested systems in North Carolina

ZIP codes served

28304 28314

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 Cliffdale West water: EPA UCMR 5 results." Data: U.S. EPA Fifth Unregulated Contaminant Monitoring Rule, final release August 2026, PWSID NC0326332. https://wellandtap.com/pfas/north-carolina/cliffdale-west/

About this data

Source: U.S. EPA, UCMR 5 occurrence data, final release August 2026 (PWSID NC0326332). Population: EPA SDWIS. Averages count results below the reporting level as zero, the same convention EPA uses for running annual averages. Full method.