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Nitrate Nitrite in U.S. tap water
153 public water systems across 19 U.S. states report Nitrate Nitrite in their annual Consumer Confidence Report. 2 sit at or above the federal limit.
At or above the federal limit (2)
| Water system | Measured | vs. limit |
|---|---|---|
| Richardson, TX 2024 annual report | 211 mg/L | 21.1× the limit |
| La Canada Irrigation Dist. — La Canada, Ca, CA 2020 annual report | 10 mg/L | 1.0× the limit |
Approaching the limit (6)
| Water system | Measured | vs. limit |
|---|---|---|
| Chapel Hill Water System, MD 2024 annual report | 9.2 mg/L | 0.9× the limit |
| Sleepy Valley Water Company — Santa Clarita, Ca, CA 2021 annual report | 9.1 mg/L | 0.9× the limit |
| Sleepy Valley Water Company — Santa Clarita, Ca, CA 2020 annual report | 9.1 mg/L | 0.9× the limit |
| Boh Nak Mhp, MD 2024 annual report | 8.3 mg/L | 0.8× the limit |
| Loma Linda, City of — Loma Linda, Ca, CA 2023 annual report | 0.47–8.2 mg/L | 0.8× the limit |
| Gaither Manor Apartments, MD 2024 annual report | 8.1 mg/L | 0.8× the limit |
Within the federal limit (145)
Showing 50 of 145. The full list is in the JSON API.
Nitrate Nitrite by state
Every state where a public water system reports Nitrate Nitrite in its annual report, ranked by systems at or above the federal limit.
Frequently asked
+What is Nitrate Nitrite?
Nitrate Nitrite is a contaminant some U.S. public water utilities measure and report in their annual Consumer Confidence Report.
+What is the federal limit for Nitrate Nitrite in drinking water?
The federal MCL for Nitrate Nitrite is 10 mg/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 Nitrate Nitrite over the federal limit?
2 of the 153 public water systems on The Water Map report Nitrate Nitrite at or above its federal limit, spanning 19 U.S. states. The full list is on this page.
+Which states report the most Nitrate Nitrite in their drinking water?
Of the systems on The Water Map, California (1 system at or above the limit), Texas (1 system at or above the limit) report the most Nitrate Nitrite exceedances. The state-by-state table on this page lists every state.
+How can I check if Nitrate Nitrite 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 Nitrate Nitrite.