PFAS ("forever chemicals")
Perfluoroheptanoic acid in U.S. tap water
132 public water systems across 19 U.S. states report Perfluoroheptanoic 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
Perfluoroheptanoic acid, a PFAS 'forever chemical.'
Why it's regulated
Monitored under EPA rules; persistent in the environment.
Within the federal limit (44)
| Water system | Measured |
|---|---|
| Albuquerque, NM 2024 annual report | Not detected ng/L |
| Boonsboro Keedysville, MD 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 ng/L |
| Chandler, AZ 2024 annual report | 0 ng/L |
| 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 |
| Edison, NJ 2024 annual report | Not detected ng/L |
| Elsinore Valley MWD — Lake Elsinore, Ca, CA 2022 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 |
| 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 |
| Los Angeles Cwwd 36-val Verde — Alhambra, Ca, CA 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 |
| North Marin Water District — Novato, Ca, CA 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 |
| St. Francis, WI 2023 annual report | Not detected ng/L |
| Suburban Water Systems-la Mirada — Covina, Ca, CA 2023 annual report | Not detected ng/L |
| Suburban Water Systems-whittier — Covina, Ca, CA 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 |
| Winston Salem, NC 2024 annual report | Not detected |
Frequently asked
+What is Perfluoroheptanoic acid?
Perfluoroheptanoic acid, a PFAS 'forever chemical.' Monitored under EPA rules; persistent in the environment.
+What is the federal limit for Perfluoroheptanoic acid in drinking water?
The federal NL for Perfluoroheptanoic 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 Perfluoroheptanoic acid over the federal limit?
Zero of the 132 public water systems in The Water Map dataset currently report Perfluoroheptanoic acid at or above its federal limit.
+How can I check if Perfluoroheptanoic 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 Perfluoroheptanoic acid.