Nitrite in U.S. Drinking Water
Health-based violation data for Nitrite from EPA Safe Drinking Water Information System (SDWIS). Covers all community water systems with violations on record.
Nitrite has been found in violation of EPA standards in 56 water systems across 8 states, with 174 total health-based violations recorded. The most affected states are Iowa, Illinois, Texas.
Nitrite 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, PlainEnviro's joined extract contains 174 health-based violation records carrying Nitrite (EPA code 1041) across 56 active community water systems in 8 states. Raw record counts are highest in Iowa, Illinois, Texas, with Iowa accounting for 58 records across 14 systems. Health-effect prose is shown only when the official ECHO substance name matches a verified topic; otherwise the portal stays silent rather than inventing guidance.
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.
Violations by State
States ranked by number of health-based violations for Nitrite.
| # | State | Violations | Systems Affected |
|---|---|---|---|
| 1 | Iowa | 58 | 14 |
| 2 | Illinois | 26 | 5 |
| 3 | Texas | 23 | 6 |
| 4 | South Dakota | 9 | 1 |
| 5 | New York | 3 | 1 |
| 6 | Arizona | 2 | 1 |
| 7 | West Virginia | 2 | 1 |
| 8 | California | 1 | 1 |
Most Affected Water Systems
Top 50 water systems by number of Nitrite health-based violations.
| Water System | State | Violations |
|---|---|---|
| KNIERIM WATER SUPPLY | IA | 25 |
| CHRISMAN | IL | 18 |
| GARDEN CITY | SD | 9 |
| D P & R WSC | TX | 8 |
| NORTH HUNT SUD | TX | 8 |
| JAMAICA WATER SUPPLY | IA | 5 |
| SHELDAHL WATER SUPPLY | IA | 4 |
| BLAIRSTOWN WATER SUPPLY | IA | 3 |
| KEYSTONE WATER SUPPLY | IA | 3 |
| CRYSTAL LAKE WATER SUPPLY | IA | 3 |
| GLENN OAKS ADDITION | IA | 3 |
| SLATER MUNI WATER DEPT | IA | 3 |
| SPIN LAKE HOMEOWNERS ASSOCIATION, INC. | IL | 3 |
| RIVERHEAD WATER DISTRICT | NY | 3 |
| Kykotsmovi | AZ | 2 |
| NEWHALL WATER SUPPLY | IA | 2 |
| LAWLER WATER SUPPLY | IA | 2 |
| WHEATLAND CITY WATER SUPPLY | IA | 2 |
| WOODLAND | IL | 2 |
| COAL VALLEY | IL | 2 |
| COLEMAN COUNTY SUD | TX | 2 |
| CITY OF BARDWELL | TX | 2 |
| CITY OF KEENE | TX | 2 |
| DANESE PSD | WV | 2 |
| BIANCHI FLOWERS INC | CA | 1 |
| APLINGTON WATER SUPPLY | IA | 1 |
| POMEROY WATER SUPPLY | IA | 1 |
| RYAN WATER SUPPLY | IA | 1 |
| ATLANTA | IL | 1 |
| CALLAHAN COUNTY WSC | TX | 1 |
Frequently Asked Questions
Is Nitrite in my water?
Nitrite has been detected in violation of EPA health standards in 56 water systems across 8 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 Nitrite violations?
EPA SDWIS records show 56 community water systems with health-based Nitrite violations, totaling 174 violations. These represent cases where the contaminant exceeded the EPA Maximum Contaminant Level (MCL).
Which states have the most Nitrite violations?
The states with the most Nitrite violations are: Iowa (58 violations), Illinois (26 violations), Texas (23 violations), South Dakota (9 violations), New York (3 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
Read our methodology - how this data is sourced, computed, and verified.