PFAS ("forever chemicals")
Perfluorohexanoic acid in U.S. tap water
226 public water systems across 28 U.S. states report Perfluorohexanoic acid in their annual Consumer Confidence Report. None currently sit at or above the federal limit.
See the PFAS Hotspots leaderboard → — every U.S. water system over EPA's finalized PFAS limit, ranked by severity, from the 2023–2025 UCMR5 lab dataset.
What it is
Perfluorohexanoic acid, a shorter-chain PFAS 'forever chemical.'
Why it's regulated
Monitored under EPA rules; persistent and widely detected.
Within the federal limit (38)
| Water system | Measured |
|---|---|
| Albuquerque, NM 2024 annual report | Not detected ng/L |
| Brown Deer, WI 2023 annual report | Not detected ng/L |
| Butler, WI 2023 annual report | Not detected ng/L |
| Calvert Manor, MD 2024 annual report | Not detected |
| Carpinteria Valley Water District — Carpinteria, Ca, CA 2023 annual report | Not detected % |
| Chesapeake, VA 2023 annual report | Not detected ng/L |
| City of Mountain House — Mountain House, Ca, CA 2023 annual report | Not detected |
| Cotati, City of — Cotati, Ca, CA 2023 annual report | Not detected ng/L |
| Dearborn, MI 2024 annual report | Not detected ng/L |
| East Valley Water District — Highland, Ca, CA 2023 annual report | Not detected ng/L |
| El Monte, CA 2024 annual report | Not detected ng/L |
| Fallbrook Pud — Fallbrook, Ca, CA 2023 annual report | Not detected ng/L |
| Fillmore Water Dept — Fillmore, Ca, CA 2023 annual report | Not detected ng/L |
| Foothill Municipal Water Dist. — La Canada Flintridge, Ca, CA 2023 annual report | Not detected ng/L |
| Franklin, WI 2023 annual report | Not detected ng/L |
| Freedom District, MD 2024 annual report | Not detected ng/L |
| Grand Rapids, MI 2025 annual report | Not detected ng/L |
| Greendale, WI 2023 annual report | Not detected ng/L |
| Greenfield, WI 2023 annual report | Not detected ng/L |
| Hales Corners, WI 2023 annual report | Not detected ng/L |
| Menomonee Falls, WI 2023 annual report | Not detected ng/L |
| Mequon, WI 2023 annual report | Not detected ng/L |
| Milwaukee, WI 2023 annual report | Not detected ng/L |
| Montecito Water Dist — Santa Barbara, Ca, CA 2023 annual report | Not detected ng/L |
| New Berlin, WI 2023 annual report | Not detected ng/L |
| Pasadena, CA 2023 annual report | Not detected ng/L |
| Salem, OR 2023 annual report | Not detected ng/L |
| Shorewood, WI 2023 annual report | Not detected ng/L |
| Solvang Water Division — Solvang, Ca, CA 2023 annual report | 0 ng/L |
| St. Francis, WI 2023 annual report | Not detected ng/L |
| Thiensville, WI 2023 annual report | Not detected ng/L |
| Tracy, CA 2024 annual report | Not detected |
| Ventura Cwwd No. 1 - Moorpark — Moorpark, Ca, CA 2023 annual report | Not detected |
| Vineyard Ave Estates Mwc — Oxnard, Ca, CA 2022 annual report | Not detected ng/L |
| Waukesha, WI 2023 annual report | Not detected ng/L |
| Wauwatosa, WI 2023 annual report | Not detected ng/L |
| West Allis, WI 2023 annual report | Not detected ng/L |
| West Valley City, UT 2024 annual report | Not detected ng/L |
Frequently asked
+What is Perfluorohexanoic acid?
Perfluorohexanoic acid, a shorter-chain PFAS 'forever chemical.' Monitored under EPA rules; persistent and widely detected.
+What is the federal limit for Perfluorohexanoic acid in drinking water?
The federal NL for Perfluorohexanoic acid is 0.003 . The EPA enforces this against the regulated reporting statistic (typically a running annual average or 90th percentile), not a single-sample spike.
+How many U.S. water systems have Perfluorohexanoic acid over the federal limit?
Zero of the 226 public water systems in The Water Map dataset currently report Perfluorohexanoic acid at or above its federal limit.
+How can I check if Perfluorohexanoic acid is in my city's tap water?
Search your city on The Water Map (https://www.thewatermap.com/) or browse the list on this page. Every U.S. public water utility is required to publish an annual Consumer Confidence Report that lists every contaminant it measured, including Perfluorohexanoic acid.