What Nitrate is, and why it's regulated
What the EPA limit means
10000 µg/L
Maximum Contaminant Level — the enforceable ceiling a supplier must stay under.
10000 µg/L
Health goal (MCLG) — the level with no known health effect. It is a goal, not a legal limit, and is often zero for carcinogens.
SYR4
Where these measurements come from. Hover the tag for the EPA programme and years.
Where Nitrate was found
The water suppliers reporting the highest levels, worst first. For lead and copper that is the 90th-percentile result the action level is written against; for Six-Year Review data, the 95th percentile of each system's samples.
| Supplier | City | State | Level vs EPA limit |
|---|---|---|---|
| California Mens Colony | San Luis Obispo | CA | 500000 µg/L 5000% of the EPA limit, at the 95th percentile of samples — 10000 µg/L |
| Cuyama Community Services District | New Cuyama | CA | 174020 µg/L 1740% of the EPA limit, at the 95th percentile of samples — 10000 µg/L |
| Farmstead Acres | Derry | NH | 86000 µg/L 860% of the EPA limit, at the 95th percentile of samples — 10000 µg/L |
| River Rd Ws #25 | Gonzales | CA | 82400 µg/L 824% of the EPA limit, at the 95th percentile of samples — 10000 µg/L |
| Chino Basin Desalter Auth. - Desalter 1 | Ontario | CA | 66218 µg/L 662% of the EPA limit, at the 95th percentile of samples — 10000 µg/L |
| Psmcsd - Springfield Ws | Royal Oaks | CA | 65406.7 µg/L 654% of the EPA limit, at the 95th percentile of samples — 10000 µg/L |
| Encinal Rd Ws #01 | Salinas | CA | 64850.7 µg/L 649% of the EPA limit, at the 95th percentile of samples — 10000 µg/L |
| Chino, City of | Chino | CA | 49720 µg/L 497% of the EPA limit, at the 95th percentile of samples — 10000 µg/L |
| Alamo Sewer and Water Gid | Alamo | NV | 49000 µg/L 490% of the EPA limit, at the 95th percentile of samples — 10000 µg/L |
| Eola Wsc | Eola | TX | 44800 µg/L 448% of the EPA limit, at the 95th percentile of samples — 10000 µg/L |
| El Camino Wc Inc | Salinas | CA | 44092.5 µg/L 441% of the EPA limit, at the 95th percentile of samples — 10000 µg/L |
| Vineyard Ave Estates Mwc | Oxnard | CA | 42262 µg/L 423% of the EPA limit, at the 95th percentile of samples — 10000 µg/L |
| Gleanings for the Hungry | Sultana | CA | 42000 µg/L 420% of the EPA limit, at the 95th percentile of samples — 10000 µg/L |
| Iverson & Jacks Apts Ws | Salinas | CA | 39000 µg/L 390% of the EPA limit, at the 95th percentile of samples — 10000 µg/L |
| Waterville Town of | Waterville | WA | 34460 µg/L 345% of the EPA limit, at the 95th percentile of samples — 10000 µg/L |
| Winterhaven County Water District | Winterhaven | CA | 32000 µg/L 320% of the EPA limit, at the 95th percentile of samples — 10000 µg/L |
| Lake Morena Views Mwc | — | CA | 32000 µg/L 320% of the EPA limit, at the 95th percentile of samples — 10000 µg/L |
| Yuima Municipal Water District Ida | Pauma Valley | CA | 31640 µg/L 316% of the EPA limit, at the 95th percentile of samples — 10000 µg/L |
| Valley Ford Water Association | Valley Ford | CA | 31640 µg/L 316% of the EPA limit, at the 95th percentile of samples — 10000 µg/L |
| Papago Butte Dwid | Maricopa | AZ | 31300 µg/L 313% of the EPA limit, at the 95th percentile of samples — 10000 µg/L |
| Marchi Central Farm | Pescadero | CA | 29380 µg/L 294% of the EPA limit, at the 95th percentile of samples — 10000 µg/L |
| San Lucas County Water District | San Lucas | CA | 27120 µg/L 271% of the EPA limit, at the 95th percentile of samples — 10000 µg/L |
| Sierra Mutual Water Company | Porterville | CA | 27120 µg/L 271% of the EPA limit, at the 95th percentile of samples — 10000 µg/L |
| Biola Community Services Dist | Biola | CA | 26095 µg/L 261% of the EPA limit, at the 95th percentile of samples — 10000 µg/L |
| Oak Lane Mobile Home Park | Stevens Point | WI | 25700 µg/L 257% of the EPA limit, at the 95th percentile of samples — 10000 µg/L |
Frequently asked questions about Nitrate
What is Nitrate in drinking water?
Nitrate comes from fertiliser, septic systems and manure; it is dangerous for infants, causing blue-baby syndrome.
What is the EPA limit for Nitrate?
The EPA's Maximum Contaminant Level for Nitrate is 10000 µg/L, and its health goal (MCLG) is 10000 µg/L. A result above the limit means the supplier must act; the goal is the level at which no health effects are expected.
How common is Nitrate in US tap water?
Of the 29,703 water suppliers with results on file, 24,520 detected Nitrate — 82.6% of those tested.