Disinfection byproducts
NDMA in U.S. tap water
39 public water systems across 3 U.S. states report NDMA in their annual Consumer Confidence Report. None currently sit at or above the federal limit.
Within the federal limit (7)
| Water system | Measured |
|---|---|
| Costa Mesa, CA 2024 annual report | Not detected ng/L |
| Covina Irrigating Co. — West Covina, Ca, CA 2023 annual report | Not detected ng/L |
| Covina Irrigating Co. — West Covina, Ca, CA 2020 annual report | Not detected ng/L |
| Covina Irrigating Co. — West Covina, Ca, CA 2021 annual report | Not detected ng/L |
| Mesa Water District — Costa Mesa, Ca, CA 2023 annual report | Not detected ng/L |
| Pomona, CA 2024 annual report | Not detected ng/L |
| Port Hueneme City Water Dept — Port Hueneme, Ca, CA 2023 annual report | Not detected ng/L |
Frequently asked
+What is NDMA?
NDMA is a contaminant some U.S. public water utilities measure and report in their annual Consumer Confidence Report.
+What is the federal limit for NDMA in drinking water?
The federal NL for NDMA 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 NDMA over the federal limit?
Zero of the 39 public water systems in The Water Map dataset currently report NDMA at or above its federal limit.
+How can I check if NDMA 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 NDMA.