Nitrate in drinking water
From fertilizer, manure and septic systems. Highest in farm-country groundwater.
Health: Dangerous for infants under 6 months (blue baby syndrome). The limit is 10 mg/L measured as nitrogen.
Across the US
495 community water systems had at least one health-based Nitrate violation since 2016. Routine Nitrate sample results are reported to states, not to EPA's national database, so this page ranks systems by violations rather than levels.
Most violations
| Water system | People | Violations |
|---|---|---|
| Franklin Water Systems 3 | 201 | 114 |
| Twin Valley Inc | 317 | 54 |
| City of Burlington | 3,720 | 45 |
| City of Quitaque | 342 | 42 |
| Turkey Municipal Water System | 317 | 42 |
| South Midland County Water System | 165 | 42 |
| Eola Water Supply Corporation | 165 | 42 |
| Greenwood Terrace M H Subdivision | 120 | 42 |
| Northside Water Supply Corporation | 250 | 41 |
| Lemon Cove Water Company | 168 | 41 |
| Canyon Dam Mobile Home Park Water System | 108 | 41 |
| Grassland Water Supply Corporation | 55 | 41 |
| Meadow Lark Court LLC | 45 | 41 |
| Whitharral Water Supply Corporation | 200 | 40 |
| Sierra Vista Association | 43 | 40 |
| Twin Oaks MHP Midland | 234 | 38 |
| Encinal Rd WS #01 Water System | 91 | 38 |
| Quiet Oaks Mobile Home Park Water System | 120 | 37 |
| Rainbird Valley Mutual Water Company | 238 | 36 |
| Psmcsd – Springfield Water System | 200 | 36 |
| River Rd WS #25 Water System | 65 | 36 |
| Martin County Fresh Water Supply District 1 | 54 | 36 |
| White Horse Ranch Owners Association | 292 | 35 |
| City of Ford | 204 | 34 |
| San Joaquin Estates Mutual Water Company | 165 | 34 |
States with the most systems with violations
- California: 119
- Texas: 84
- Kansas: 45
- Arizona: 41
- Washington: 34
- Pennsylvania: 20
- Iowa: 14
- Colorado: 13
- Idaho: 13
- Minnesota: 11
- Illinois: 11
- Wisconsin: 11
Sources
The limits, health goals and health effects on this page come from these EPA sources. The results come from EPA's monitoring data for each water system.
- EPA: National Primary Drinking Water Regulations (limits and health effects table)
- EPA ECHO: Safe Drinking Water Information System data
This page summarizes public regulatory information. It is not medical advice. How we source and check this site.
Questions
What is the safe level of Nitrate in drinking water?
The federal legal limit (MCL) is 10 ppm. EPA's health goal (MCLG), the level with no known risk, is 10 ppm.
How do I remove Nitrate from tap water?
See the filter guidance on this page: look for a product certified for Nitrate specifically, and check the claim in NSF's certified product listings.
Source: U.S. EPA drinking water records and PFAS testing (UCMR 5). How we read the data.