Other
Nitrate Nitrite in U.S. tap water
127 public water systems across 1 U.S. states report Nitrate Nitrite in their annual Consumer Confidence Report. 4 sit at or above the federal limit.
127
systems measuring
4
over the limit
1
states represented
At or above the federal limit (4)
| Water system | Measured | vs. limit |
|---|---|---|
| Pomona - City, Water Dept., CA 2023 annual report | 12.933333333333332 MG/L | 1.3× the limit |
| Pomona - City, Water Dept., CA 2026 annual report | 11.683333333333334 MG/L | 1.2× the limit |
| Pomona - City, Water Dept., CA 2025 annual report | 10.988461538461538 MG/L | 1.1× the limit |
| Oxnard, CA 2024 annual report | 10.266666666666666 MG/L | 1.0× the limit |
Approaching the limit (3)
| Water system | Measured | vs. limit |
|---|---|---|
| Riverside, City of, CA 2026 annual report | 9.7 MG/L | 1.0× the limit |
| Cwsc Salinas, CA 2023 annual report | 9.2 MG/L | 0.9× the limit |
| SFPUC City Distribution Division, CA 2024 annual report | 8.886 MG/L | 0.9× the limit |
Within the federal limit (120)
| Water system | Measured |
|---|---|
| Saticoy Country Club-city of Ventura, CA 2024 annual report | 7.85 MG/L |
| San Francisco SFPUC, CA 2023 annual report | 7.81 MG/L |
| SFPUC City Distribution Division, CA 2025 annual report | 7.581666666666667 MG/L |
| Cwsc Salinas, CA 2026 annual report | 7.072413793103448 MG/L |
| Golden State Water Company - Los Osos, CA 2025 annual report | 6.975 MG/L |
| Riverside, City of, CA 2025 annual report | 6.203333333333333 MG/L |
| Glendale-city, Water Dept., CA 2023 annual report | 6.11578947368421 MG/L |
| Oxnard Water Dept, CA 2025 annual report | 5.766666666666667 MG/L |
| Cwsc Salinas, CA 2024 annual report | 5.55125 MG/L |
| San Gabriel Valley Wc - Fontana, CA 2026 annual report | 5.4 MG/L |
| Cws - Visalia, CA 2025 annual report | 5.266666666666667 MG/L |
| Cws - Visalia, CA 2026 annual report | 5.2 MG/L |
| Cwsc Salinas, CA 2025 annual report | 4.9624999999999995 MG/L |
| Rancho Estates Mutual Water Co., CA 2026 annual report | 4.7275 MG/L |
| El Monte-city, Water Dept., CA 2026 annual report | 4.6 MG/L |
| San Gabriel Valley Wc - Fontana, CA 2025 annual report | 4.542857142857143 MG/L |
| San Gabriel Valley Wc - Fontana, CA 2024 annual report | 4.42 MG/L |
| Pasadena Water and Power, CA 2025 annual report | 4.3 MG/L |
| Ontario Municipal Utilities Company, CA 2023 annual report | 4.041176470588235 MG/L |
| City of Santa Clara, CA 2025 annual report | 3.95 MG/L |
| Irvine Ranch Water District, CA 2024 annual report | 3.8485185185185187 MG/L |
| Cal-water Service Co.-chico, CA 2026 annual report | 3.6222222222222222 MG/L |
| Cal-water Service Co.-chico, CA 2025 annual report | 3.6 MG/L |
| City of Cupertino, CA 2025 annual report | 3.6 MG/L |
| Rialto, City of, CA 2026 annual report | 3.55 MG/L |
| City of Stockton, CA 2025 annual report | 3.436666666666666 MG/L |
| Clovis, CA 2024 annual report | 3.4081249999999996 MG/L |
| City of Fullerton, CA 2025 annual report | 3.345 MG/L |
| City of Fullerton, CA 2023 annual report | 3.291333333333333 MG/L |
| Irvine Ranch Water District, CA 2025 annual report | 3.2861971830985914 MG/L |
| City of Clovis, CA 2023 annual report | 3.232875 MG/L |
| San Gabriel Valley Wc - Fontana, CA 2023 annual report | 3.1919999999999997 MG/L |
| Cws - Visalia, CA 2023 annual report | 3.155625 MG/L |
| City of Clovis, CA 2025 annual report | 3.0751315789473685 MG/L |
| Sunnyvale, CA 2024 annual report | 3.0285714285714285 MG/L |
| City of Clovis, CA 2026 annual report | 2.925 MG/L |
| Rialto, CA 2024 annual report | 2.9 MG/L |
| City of Santa Ana, CA 2025 annual report | 2.865217391304348 MG/L |
| City of Fullerton, CA 2026 annual report | 2.718888888888889 MG/L |
| Fullerton, CA 2024 annual report | 2.7170588235294115 MG/L |
| Irvine, CA 2023 annual report | 2.682241379310345 MG/L |
| Visalia, CA 2024 annual report | 2.5889655172413795 MG/L |
| Los Angeles LADWP, CA 2023 annual report | 2.5504615384615383 MG/L |
| Valley Estates Poa, Inc., CA 2025 annual report | 2.55 MG/L |
| Ontario, CA 2024 annual report | 2.5 MG/L |
| Santa Ana, CA 2024 annual report | 2.4735294117647055 MG/L |
| City of Santa Ana, CA 2023 annual report | 2.4664285714285716 MG/L |
| Rialto, City of, CA 2023 annual report | 2.45 MG/L |
| Rialto, City of, CA 2025 annual report | 2.442857142857143 MG/L |
| Ventura Wwd No. 8 - Simi Valley, CA 2025 annual report | 2.4 MG/L |
Showing 50 of 120. The full list is in the JSON API.
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?
4 of the 127 public water systems on The Water Map report Nitrate Nitrite at or above its federal limit, spanning 1 U.S. states. The full list is on this page.
+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.