PFAS in tap water, Barnstable, Massachusetts
2 of 4 water systems had PFAS-4 above our 0.5 ng/L benchmark at the latest sample. Highest: Barnstable Fire District, 4.9 ng/L. 2 had PFOA or PFOS above the 4 ng/L federal MCL in at least one sample.
Barnstable is served by 4 community water systems · 95,338 people served
Water systems serving Barnstable
| Water system | People served | PFAS-4 at the latest sample | Entry points | Latest sample |
|---|---|---|---|---|
| Centerville Osterville Marstons Mills WD | 50,000 | 4.8 ng/L above the 2029 federal MCL | 15 | October 1, 2025 |
| Hyannis Water System, Town of Barnstable | 35,000 | below the 3 to 4 ng/L reporting limit | 3 | April 9, 2024 |
| Barnstable Fire District | 5,400 | 4.9 ng/L above the 2029 federal MCL | 3 | October 17, 2023 |
| Cotuit Fire District Water Department | 4,938 | below the 3 to 4 ng/L reporting limit | 5 | September 19, 2023 |
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.
Census place "Barnstable Town city", matched from the city rows the systems report to SDWIS.
County
ZIP codes in Barnstable
Census ZIP code tabulation areas with at least 5 % of their land inside this city or town.
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.