Coliform (Pre-TCR) in U.S. Drinking Water
Health-based violation data for Coliform (Pre-TCR) from EPA Safe Drinking Water Information System (SDWIS). Covers all community water systems with violations on record.
Coliform (Pre-TCR) has been found in violation of EPA standards in 3,444 water systems across 20 states, with 8,921 total health-based violations recorded. The most affected states are Oklahoma, Nebraska, California.
Coliform (Pre-TCR) 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 8,921 health-based violation records carrying Coliform (Pre-TCR) (EPA code 3000) across 3,444 active community water systems in 20 states. Raw record counts are highest in Oklahoma, Nebraska, California, with Oklahoma accounting for 1,511 records across 455 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 Coliform (Pre-TCR).
| # | State | Violations | Systems Affected |
|---|---|---|---|
| 1 | Oklahoma | 1,511 | 455 |
| 2 | Nebraska | 250 | 126 |
| 3 | California | 13 | 7 |
| 4 | Louisiana | 13 | 4 |
| 5 | Iowa | 12 | 1 |
| 6 | Kansas | 9 | 2 |
| 7 | West Virginia | 8 | 6 |
| 8 | Puerto Rico | 7 | 1 |
| 9 | Tennessee | 5 | 2 |
| 10 | Colorado | 4 | 1 |
| 11 | Oregon | 4 | 1 |
| 12 | Arizona | 3 | 1 |
| 13 | Idaho | 3 | 1 |
| 14 | Minnesota | 3 | 1 |
| 15 | Texas | 3 | 2 |
| 16 | Missouri | 2 | 1 |
| 17 | Nevada | 2 | 1 |
| 18 | South Dakota | 2 | 1 |
| 19 | Washington | 2 | 1 |
| 20 | New Jersey | 1 | 1 |
Most Affected Water Systems
Top 50 water systems by number of Coliform (Pre-TCR) health-based violations.
Frequently Asked Questions
Is Coliform (Pre-TCR) in my water?
Coliform (Pre-TCR) has been detected in violation of EPA health standards in 3,444 water systems across 20 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 Coliform (Pre-TCR) violations?
EPA SDWIS records show 3,444 community water systems with health-based Coliform (Pre-TCR) violations, totaling 8,921 violations. These represent cases where the contaminant exceeded the EPA Maximum Contaminant Level (MCL).
Which states have the most Coliform (Pre-TCR) violations?
The states with the most Coliform (Pre-TCR) violations are: Oklahoma (1,511 violations), Nebraska (250 violations), California (13 violations), Louisiana (13 violations), Iowa (12 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.