PFAS ("forever chemicals") · 2023
PFOS in Philadelphia, PA tap water
Philadelphia, PA's 2023 PFOS level is between 80% and 100% of the federal limit (4 ng/L MCL) — measured but not in violation.
The measurement
| Statistic | Value | Federal limit |
|---|---|---|
Maximum System-wide | 5.5 ng/L | 4 ng/L MCL |
Range System-wide | 0–5.5 ng/L | 4 ng/L MCL |
Average System-wide | 3.6 ng/L | None set |
Range System-wide | 0–6 ng/L | None set |
Verbatim from Philadelphia, PA's 2023 Consumer Confidence Report — source document ↗
About PFOS
Perfluorooctanesulfonic acid, a PFAS 'forever chemical' once used in firefighting foam and coatings.
Linked to cancer, thyroid disease, and immune effects; the EPA set an enforceable limit of 4 parts per trillion.
People also ask
+Is there PFOS in Philadelphia, PA tap water?
Yes — Philadelphia, PA's 2023 Consumer Confidence Report lists PFOS at 3.6 ng/L. Philadelphia, PA's 2023 PFOS level is between 80% and 100% of the federal limit (4 ng/L MCL) — measured but not in violation.
+What's the federal limit for PFOS in drinking water?
The federal MCL for PFOS is 4 ng/L. The EPA enforces this against the regulated reporting statistic (running annual average or 90th percentile), not a single-sample spike.
+What is PFOS?
Perfluorooctanesulfonic acid, a PFAS 'forever chemical' once used in firefighting foam and coatings. Linked to cancer, thyroid disease, and immune effects; the EPA set an enforceable limit of 4 parts per trillion.
+Where does this PFOS measurement come from?
This page reproduces the PFOS entry from the 2023 Consumer Confidence Report published by the Philadelphia, PA water utility — the annual drinking-water report every U.S. utility is required by federal law to publish. The original source document is archived at /water/pa/philadelphia/2023/source.