PFAS ("forever chemicals")
Perfluorononanoic acid in U.S. tap water
109 public water systems across 20 U.S. states report Perfluorononanoic acid in their annual Consumer Confidence Report. 5 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
Perfluorononanoic acid, a PFAS 'forever chemical.'
Why it's regulated
Regulated by the EPA at 10 parts per trillion and included in the PFAS Hazard Index.
At or above the federal limit (5)
| Water system | Measured | vs. limit |
|---|---|---|
| Backbone Mountain Boys Camp, MD 2024 annual report | 10 ng/L | 1.0× the limit |
| Campus Hills, MD 2024 annual report | 10 ng/L | 1.0× the limit |
| Cheltenham Youth Facility, MD 2024 annual report | 10 ng/L | 1.0× the limit |
| Eastern Correctional Institute, MD 2024 annual report | 10 ng/L | 1.0× the limit |
| Town of Accident, MD 2024 annual report | 10 ng/L | 1.0× the limit |
Within the federal limit (104)
| Water system | Measured |
|---|---|
| Atascadero Mutual Water Co — Atascadero, Ca, CA 2023 annual report | 5.5 ng/L |
| City of Hialeah, FL 2023 annual report | 0–5 ng/L |
| City of North Miami Beach, FL 2023 annual report | 0–5 ng/L |
| Miami Dade, FL 2023 annual report | 0–5 ng/L |
| Goodyear, AZ 2024 annual report | 4 ng/L |
| Orchard Dale Water District — Whittier, Ca, CA 2022 annual report | 2.1–2.8 ng/L |
| City of Bell Gardens — Downey, Ca, CA 2023 annual report | 2.7 ng/L |
| Orchard Dale Water District — Whittier, Ca, CA 2021 annual report | 2.66 ng/L |
| Mendota, City of — Mendota, Ca, CA 2023 annual report | 2.5 ng/L |
| City of Bell Gardens — Downey, Ca, CA 2022 annual report | 2.2 ng/L |
| Pico Rivera - City, Water Dept. — Pico Rivera, Ca, CA 2023 annual report | 1.9 ng/L |
| Atascadero State Hospital — Atascadero, Ca, CA 2022 annual report | 1.8 ng/L |
| Suburban Water Systems-la Mirada — Covina, Ca, CA 2022 annual report | 1.4 ng/L |
| Suburban Water Systems-whittier — Covina, Ca, CA 2023 annual report | 1.4 ng/L |
| Pico Rivera - City, Water Dept. — Pico Rivera, Ca, CA 2022 annual report | 1.3 ng/L |
| Bend, OR 2025 annual report | 1.2 ng/L |
| Boh Nak Mhp, MD 2024 annual report | 1.1 ng/L |
| Commerce-city, Water Dept. — San Jose, Ca, CA 2022 annual report | 1.1 ng/L |
| Commerce-city, Water Dept. — San Jose, Ca, CA 2023 annual report | 1 ng/L |
| Scwa - Laguna/vineyard — Sacramento, Ca, CA 2023 annual report | 1 ng/L |
| Suburban Water Systems-la Mirada — Covina, Ca, CA 2023 annual report | 1 ng/L |
| Philadelphia, PA 2023 annual report | 0.8 ng/L |
| Newark, NJ 2024 annual report | 0.69 ng/L |
| Green Bay, WI 2024 annual report | 0.57 ng/L |
| Saint Paul, MN 2024 annual report | 0–0.37 ng/L |
| Thornton, CO 2024 annual report | 0.1–0.3 ng/L |
| Rockville, MD 2024 annual report | 0.27 ng/L |
| Bakersfield, CA 2024 annual report | 0.01 ng/L |
| Cws - Bakersfield — San Jose, Ca, CA 2023 annual report | 0.01 ng/L |
| Albuquerque, NM 2024 annual report | Not detected ng/L |
| Anchorage, AK 2024 annual report | Not detected ng/L |
| Bellflower Municipal Water System — Rosemead, Ca, CA 2023 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 |
| Cal American Water Co — Rosemead, Ca, CA 2023 annual report | Not detected ng/L |
| Cal-am Water Company - Duarte — Rosemead, Ca, CA 2023 annual report | Not detected ng/L |
| Cal/am Water Company - Baldwin Hills — Rosemead, Ca, CA 2023 annual report | Not detected ng/L |
| Calvert Manor, MD 2024 annual report | Not detected ng/L |
| Carpinteria Valley Water District — Carpinteria, Ca, CA 2023 annual report | Not detected ng/L |
| Chandler, AZ 2024 annual report | Not detected ng/L |
| Chesapeake, VA 2023 annual report | Not detected ng/L |
| Cincinnati, OH 2024 annual report | Not detected ng/L |
| City of Baltimore, MD 2024 annual report | Not detected ng/L |
| City of Mountain House — Mountain House, Ca, CA 2023 annual report | Not detected ng/L |
| City of Pleasanton — Pleasanton, Ca, CA 2023 annual report | Not detected ng/L |
| 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 |
Showing 50 of 104. The full list is in the JSON API.
Frequently asked
+What is Perfluorononanoic acid?
Perfluorononanoic acid, a PFAS 'forever chemical.' Regulated by the EPA at 10 parts per trillion and included in the PFAS Hazard Index.
+What is the federal limit for Perfluorononanoic acid in drinking water?
The federal MCL for Perfluorononanoic acid is 10 ng/L. 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 Perfluorononanoic acid over the federal limit?
5 of the 109 public water systems on The Water Map report Perfluorononanoic acid at or above its federal limit, spanning 20 U.S. states. The full list is on this page.
+How can I check if Perfluorononanoic 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 Perfluorononanoic acid.