PFAS in tap water, Delaware County, Pennsylvania
None of the 2 water systems had a PFAS-4 compound above the 3 to 4 ng/L reporting limits at the latest sample. That's below the lab limit, not zero. 2 had PFOA or PFOS above the 4 ng/L federal MCL in at least one sample.
2 community water systems · 148,246 people served · newest sample October 20, 2025
Water systems in Delaware County
| Water system | People served | PFAS-4 at the latest sample | Entry points | Latest sample |
|---|---|---|---|---|
| Chester Water Authority | 140,437 | below the 3 to 4 ng/L reporting limit above the 2029 federal MCL in an earlier sample | 1 | November 13, 2024 |
| Veolia Water Bethel | 7,809 | below the 3 to 4 ng/L reporting limit above the 2029 federal MCL in an earlier sample | 4 | October 20, 2025 |
Not sure which one is yours? The systems report their own service areas to EPA. Check your water bill or your utility's Consumer Confidence Report.
ZIP codes in Delaware County
Census ZIP code tabulation areas that overlap the county. A ZIP served by one system opens that system's page; a ZIP shared by several systems lists them.
How to read these numbers
We compare PFAS-4 (PFOA + PFOS + PFNA + PFHxS) with this site's 0.5 ng/L benchmark, the same line as on the European pages. UCMR 5 reporting limits are 3 to 4 ng/L. So any quantified PFAS-4 compound is above the benchmark, and a clean result reads "below the 3 to 4 ng/L reporting limit", never zero. The US legal limit is the 4 ng/L federal MCL for PFOA and PFOS, which systems must meet from April 26, 2029 ("above the 2029 federal MCL").
EPA: "UCMR 5 results do not indicate compliance or noncompliance with the PFAS drinking water standards". Samples are taken where water enters the distribution system, not at your tap. A system may have changed sources or added treatment since. Source: U.S. Environmental Protection Agency (EPA), Office of Water, PFAS National Primary Drinking Water Regulation (NPDWR). Regulation details retrieved September 19, 2026. Every system page tracks the 2029 compliance date and the proposed rescission of the PFHxS, PFNA, HFPO-DA and Hazard Index limits.
This site is a data project, not an official source. If in doubt, check with your water supplier or local authority.