Nitrate in U.S. Drinking Water
Health-based violation data for Nitrate from EPA Safe Drinking Water Information System (SDWIS). Covers all community water systems with violations on record.
Nitrate has been found in violation of EPA standards in 2,216 water systems across 38 states, with 22,209 total health-based violations recorded. The most affected states are California, Texas, Kansas.
Nitrate is regulated under the EPA Safe Drinking Water Act, which sets enforceable Maximum Contaminant Levels (MCLs) and associated treatment technique requirements for public water systems. The EPA Safe Drinking Water Information System (SDWIS) tracks every recorded violation nationwide and links it back to the specific public water system (PWSID), violation type, and begin date.
Across the United States, SDWIS records show 22,209 health-based violations for Nitrate affecting 2,216 community water systems in 38 states. Violation counts cluster heaviest in California, Texas, Kansas, with California alone accounting for 2,428 violations across 136 systems. EPA health-effect summaries describe the specific exposure concerns that drove the federal standard.
A health-based violation does not mean residents were necessarily harmed, it means the contaminant exceeded the federal MCL in a compliance sample, triggering notification and remediation requirements. States and utilities maintain primary enforcement responsibility. To check the status of a specific water system, request its most recent Consumer Confidence Report or consult the EPA's Drinking Water Watch portal for the corresponding state.
What are the health effects of this contaminant?
Nitrate in drinking water at high levels is especially harmful to infants, potentially causing "blue baby syndrome" (methemoglobinemia), which reduces blood's ability to carry oxygen.
Source: U.S. Environmental Protection Agency. Consult your doctor for personalized health guidance U.S. Environmental Protection Agency. Consult your doctor for personalized health guidance
Violations by State
States ranked by number of health-based violations for Nitrate.
| # | State | Violations | Systems Affected |
|---|---|---|---|
| 1 | California | 2,428 | 136 |
| 2 | Texas | 2,309 | 75 |
| 3 | Kansas | 813 | 48 |
| 4 | Washington | 582 | 40 |
| 5 | Arizona | 581 | 31 |
| 6 | Oklahoma | 333 | 53 |
| 7 | Missouri | 296 | 7 |
| 8 | Idaho | 210 | 13 |
| 9 | Colorado | 153 | 17 |
| 10 | New Mexico | 100 | 1 |
| 11 | Iowa | 97 | 15 |
| 12 | Illinois | 74 | 11 |
| 13 | Pennsylvania | 73 | 20 |
| 14 | Delaware | 72 | 10 |
| 15 | Nebraska | 71 | 33 |
| 16 | Indiana | 65 | 5 |
| 17 | Massachusetts | 54 | 2 |
| 18 | Minnesota | 49 | 11 |
| 19 | New Jersey | 47 | 9 |
| 20 | Oregon | 39 | 6 |
| 21 | Florida | 37 | 4 |
| 22 | New York | 31 | 10 |
| 23 | Wisconsin | 29 | 16 |
| 24 | New Hampshire | 28 | 4 |
| 25 | Michigan | 26 | 6 |
| 26 | West Virginia | 19 | 1 |
| 27 | Alaska | 18 | 1 |
| 28 | North Carolina | 16 | 4 |
| 29 | Utah | 10 | 4 |
| 30 | Maine | 8 | 3 |
| 31 | Maryland | 8 | 4 |
| 32 | Vermont | 8 | 2 |
| 33 | Rhode Island | 5 | 2 |
| 34 | Ohio | 4 | 2 |
| 35 | Connecticut | 3 | 1 |
| 36 | Kentucky | 2 | 1 |
| 37 | South Dakota | 2 | 1 |
| 38 | Nevada | 1 | 1 |
Most Affected Water Systems
Top 50 water systems by number of Nitrate health-based violations.
Frequently Asked Questions
Is Nitrate in my water?
Nitrate has been detected in violation of EPA health standards in 2,216 water systems across 38 states. To check your specific utility, look up your annual Consumer Confidence Report (CCR) - water systems are required to disclose all violations.
How many water systems have Nitrate violations?
EPA SDWIS records show 2,216 community water systems with health-based Nitrate violations, totaling 22,209 violations. These represent cases where the contaminant exceeded the EPA Maximum Contaminant Level (MCL).
Which states have the most Nitrate violations?
The states with the most Nitrate violations are: California (2,428 violations), Texas (2,309 violations), Kansas (813 violations), Washington (582 violations), Arizona (581 violations).
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About This Data
Violation data is from the EPA Safe Drinking Water Information System (SDWIS). Only health-based violations are shown, these include Maximum Contaminant Level (MCL) and Treatment Technique (TT) violations. Monitoring and reporting violations are excluded. Data may not reflect the most current enforcement actions.
Source: U.S. Environmental Protection Agency, SDWIS Federal Reporting Services U.S. Environmental Protection Agency, SDWIS Federal Reporting Services
Read our methodology - how this data is sourced, computed, and verified.