E. coli (Escherichia coli) in drinking water
3,834 active public water systems in 44 states had a E. coli (Escherichia coli) violation in the past three years, and 2,209 had one in the latest quarter of EPA's data.
You are on Tapcensus, an independent guide to the EPA compliance records of every public water system in the United States. This page explains E. coli (Escherichia coli) and lists the water systems whose records include a related violation. It does not show measured levels.
Is E. coli (Escherichia coli) in the records for your water system?
Enter a ZIP code, town, or street address to see the water systems that serve your area, their status, and which rules and contaminants appear in their violations.
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What it is and where it comes from
E. coli is a fecal indicator bacterium. Its presence in treated water is an acute health violation, meaning the system must notify customers within 24 hours. Detection requires immediate corrective action — typically a boil water advisory, investigation of contamination source, and system flushing.
Health effects
Most E. coli strains cause diarrheal illness. Some strains (e.g., O157:H7) produce toxins causing severe bloody diarrhea, hemolytic uremic syndrome (HUS — a form of kidney failure), and death — especially in children under 5 and the elderly. Even non-pathogenic strains in drinking water indicate that disease-causing organisms may also be present.
The standard and what a violation means
EPA limit: Zero (one confirmed positive sample = acute MCL violation).
Water systems with a E. coli (Escherichia coli) violation, by state
Active public water systems that reported at least one related violation to EPA in the past three years. Each state links to the list of its affected systems.
| State | Systems with violations, 3 yr | Share of active systems | In violation, latest quarter |
|---|---|---|---|
| Florida | 1,676 | 33% | 239 |
| Texas | 233 | 3% | 233 |
| Oregon | 204 | 8% | 204 |
| Pennsylvania | 174 | 2% | 173 |
| New Jersey | 154 | 5% | 146 |
| Oklahoma | 148 | 11% | 148 |
| Idaho | 132 | 7% | 98 |
| North Carolina | 129 | 3% | 126 |
| Connecticut | 119 | 5% | 64 |
| Montana | 75 | 3% | 75 |
| Colorado | 73 | 3% | 20 |
| Indiana | 71 | 2% | 71 |
| Michigan | 70 | 1% | 67 |
| Missouri | 53 | 2% | 51 |
| Vermont | 44 | 3% | 44 |
| Georgia | 43 | 2% | 43 |
| Arizona | 38 | 2% | 38 |
| Ohio | 37 | 1% | 35 |
| Utah | 36 | 3% | 36 |
| Maine | 32 | 2% | 32 |
| New Mexico | 31 | 3% | 31 |
| Alaska | 29 | 2% | 19 |
| Wyoming | 27 | 3% | 27 |
| Virginia | 26 | 1% | 26 |
| Massachusetts | 25 | 2% | 25 |
| California | 22 | 0% | 21 |
| Tennessee | 16 | 2% | 16 |
| Iowa | 12 | 1% | 11 |
| Illinois | 12 | 0% | 11 |
| New Hampshire | 12 | 0% | 12 |
| South Carolina | 12 | 1% | 12 |
| Rhode Island | 11 | 3% | 1 |
| Arkansas | 10 | 1% | 10 |
| Wisconsin | 9 | 0% | 9 |
| North Dakota | 7 | 2% | 7 |
| Washington | 7 | 0% | 6 |
| Louisiana | 6 | 0% | 6 |
| Nevada | 5 | 1% | 4 |
| New York | 5 | 0% | 4 |
| South Dakota | 5 | 1% | 5 |
| Alabama | 1 | 0% | 1 |
| District of Columbia | 1 | 7% | 1 |
| Minnesota | 1 | 0% | 0 |
| Nebraska | 1 | 0% | 1 |
Largest water systems with a E. coli (Escherichia coli) violation
The ten biggest systems, by people served, whose records include a related violation in the past three years.
| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Pembroke Pines, City of Pembroke Pines · Broward County |
187,459 | 5 | 3 | |
|
Fort Lauderdale, City of Ft Lauderdale · Broward County |
185,163 | 5 | 2 | |
|
Hollywood, City of Hollywood · Broward County |
147,566 | 5 | 2 | |
|
Miramar (east ; West) Plants Miramar · Broward County |
137,107 | 5 | 2 | |
|
West Palm Beach Wtp West Palm Beach · Palm Beach County |
132,000 | 2 | 1 | |
|
Boynton Beach PWS Boynton Beach · Palm Beach County |
112,000 | 6 | 0 | |
|
Jupiter Public Water System,town of Jupiter · Palm Beach County |
94,929 | 4 | 0 | |
|
Winter Haven Water Department Winter Haven · Polk County |
87,537 | 2 | 1 | |
|
Aqua WSC Bastrop County |
86,325 | 5 | 1 | |
|
Naples Water Dept Naples · Collier County |
83,804 | 2 | 2 |
About this data
A system is counted once if any of its violations in the past three years involved E. coli (Escherichia coli), including monitoring and reporting lapses. Rules violated and status in the systems table are for the whole system, not E. coli (Escherichia coli) alone. Counts cover active systems in all 50 states and the District of Columbia.
Source: the U.S. EPA's Enforcement and Compliance History Online system (ECHO), which publishes the federal Safe Drinking Water Information System. EPA's terms and values are shown as published. The records are from EPA's data refresh of Oct 7, 2026; EPA refreshes this data quarterly, and states report to EPA with a lag of three to six months, so the newest violations may not appear yet.