Is there PFAS in Wilmington Water Department water?
Yes. EPA's final UCMR 5 results show Wilmington Water Department averaged 7.7 ppt of PFOA at its worst sampling point, 1.9 times the EPA limit of 4 ppt.
Wilmington Water Department
Serves 107,976 people · 8 PFOA samples from 2 sampling points · Feb 2023 to Jan 2024
Average above an EPA limit
PFOA Perfluorooctanoic acid
7.7 ppt avg · max 9.9
PFOS Perfluorooctanesulfonic acid
not detected
Hazard index GenX, PFBS, PFNA, PFHxS combined
not detected
Also detected, no federal limit: PFPeA, PFHxA, PFBA, PFHpA, PFBS.
Wilmington Water Department is a public water system drawing on surface water, based in Wilmington, Delaware, serving about 107,976 people, including Upper Darby, Bear, Newark, Hockessin, Kirkwood, Montchanin. Under EPA's Fifth Unregulated Contaminant Monitoring Rule it was tested for 29 PFAS and lithium 8 times across 2 sampling points between Feb 2023 and Jan 2024.
Every PFAS detected
Not detected: 8:2 FTS, NFDHA, PFHpS, PFTA, PFNA, PFMBA, PFMPA, PFEESA, 4:2 FTS, PFOS, NEtFOSAA, PFTrDA, PFDoA, 6:2 FTS, HFPO-DA, ADONA, 9Cl-PF3ONS, 11Cl-PF3OUdS, PFPeS, PFDA, PFHxS, NMeFOSAA, PFUnA.
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 Delaware
All 36 tested systems in Delaware
ZIP codes served
19082 19701 19702 19707 19708 19710 19720 19732 19801 19802 19803 19804 19805 19806 19807 19808 19809 19810 19850 19880 19884 19898 19899
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 Wilmington Water Department water: EPA UCMR 5 results." Data: U.S. EPA Fifth Unregulated Contaminant Monitoring Rule, final release August 2026, PWSID DE0000663. https://wellandtap.com/pfas/delaware/wilmington-water-department/
About this data
Source: U.S. EPA, UCMR 5 occurrence data, final release August 2026 (PWSID DE0000663). Population: EPA SDWIS. Averages count results below the reporting level as zero, the same convention EPA uses for running annual averages. Full method.
