Drinking Water Safety
Explore 434,040 public water systems and 15,432,737 EPA drinking water violations across 65 states. Find water quality data from the EPA Safe Drinking Water Information System.
Browse by State
View public water systems and violations by state. Check which states have the most drinking water issues on record.
Browse by System Type
Filter water systems by type: Community (CWS), Non-Transient Non-Community (NTNCWS), or Transient Non-Community (TNCWS).
Top Violated Water Systems
Public water systems with the highest number of EPA drinking water violations on record.
| # | Water System | State | Violations |
|---|---|---|---|
| 1 | HERNDON COMMUNITY WATER | West Virginia | 15,272 |
| 2 | PIERPOINT WATER | West Virginia | 13,208 |
| 3 | KANAWHA FALLS COMMUNITY WATER | West Virginia | 12,680 |
| 4 | CONGREGATION OHR MENACHEM | Pennsylvania | 11,851 |
| 5 | SEVEN ESTATES | Texas | 11,585 |
| 6 | OTOOLE WATER | West Virginia | 11,548 |
| 7 | PINNACLE WATER ASSOCIATION | West Virginia | 11,432 |
| 8 | COAL MOUNTAIN WATER | West Virginia | 10,957 |
| 9 | EASTSIDE MHP | Oklahoma | 9,971 |
| 10 | LAKE FOREST PARK WATER DISTRICT | Washington | 9,527 |
Water Systems by State
States with the most registered public water systems.
| # | State | Systems |
|---|---|---|
| 1 | Michigan | 26,704 |
| 2 | Illinois | 25,185 |
| 3 | New York | 24,703 |
| 4 | North Carolina | 23,682 |
| 5 | Pennsylvania | 22,494 |
| 6 | Wisconsin | 22,144 |
| 7 | Minnesota | 21,653 |
| 8 | California | 19,626 |
| 9 | Florida | 19,277 |
| 10 | Texas | 16,244 |
How It Works
Search Water Systems
Browse 434,040 public water systems by state, type, or name. Each system includes its EPA identifier, population served, and water source type.
Review Violations
Check 15,432,737 drinking water violations. See which contaminants were found, whether they were health-based, and the compliance status of each violation.
Analyze Trends
View statistics on the most common contaminants, violation trends by year, and which states have the most water quality issues. 1,993,255 health-based violations have been recorded.
Frequently Asked Questions
The Safe Drinking Water Information System (SDWIS) is the EPA's database of all public water systems in the United States and their compliance with the Safe Drinking Water Act. It tracks 434,040 water systems across 65 states, recording violations for contaminants like lead, arsenic, nitrates, coliform bacteria, and disinfection byproducts.
Health-based violations occur when a water system exceeds the Maximum Contaminant Level (MCL) set by the EPA for a specific substance, or fails to properly treat drinking water. These violations indicate a potential health risk. Our database contains 1,993,255 health-based violations. Non-health violations typically involve monitoring, reporting, or administrative requirements.
Community Water Systems (CWS) serve the same population year-round (cities, towns, mobile home parks). Non-Transient Non-Community (NTNCWS) serve 25+ of the same people for 6+ months per year (schools, factories). Transient Non-Community (TNCWS) serve transient populations (rest stops, campgrounds). All three types must comply with federal drinking water standards.
All data comes from the EPA's ECHO (Enforcement and Compliance History Online) system, which publishes SDWIS data downloads at echo.epa.gov. The dataset includes water system information, violation records, contaminant details, and compliance status for all regulated public water systems in the United States.