Drinking Water Safety
Explore 433,347 public water systems and 12,049,741 EPA drinking water violations across 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 | WV | 0 |
| 2 | PIERPOINT WATER | WV | 0 |
| 3 | KANAWHA FALLS COMMUNITY WATER | WV | 0 |
| 4 | OTOOLE WATER | WV | 0 |
| 5 | SEVEN ESTATES | TX | 0 |
| 6 | PINNACLE WATER ASSOCIATION | WV | 0 |
| 7 | COAL MOUNTAIN WATER | WV | 0 |
| 8 | CONGREGATION OHR MENACHEM | PA | 0 |
| 9 | LAKE FOREST PARK WATER DISTRICT | WA | 0 |
| 10 | TIMBER CREEK MHP EAST & WEST | OK | 0 |
| 11 | BROOKSIDE OTSEGO COMMUNITY WATER | WV | 0 |
| 12 | RIDGEDALE HOA | NC | 0 |
| 13 | DUO WATER WORKS | WV | 0 |
| 14 | SKYVIEW ESTATES | IL | 0 |
| 15 | UPCC INDIAN RIDGE | WV | 0 |
Top Contaminants
Most frequently cited contaminants in EPA drinking water violations.
| # | Contaminant | Violations |
|---|---|---|
| 1 | Coliform (TCR) | 632,869 |
| 2 | TTHM | 203,703 |
| 3 | Arsenic | 106,569 |
| 4 | Nitrate | 92,628 |
| 5 | Total Haloacetic Acids (HAA5) | 91,815 |
| 6 | Surface Water Treatment Rule | 81,115 |
| 7 | Combined Radium (-226 and -228) | 69,422 |
| 8 | Revised Total Coliform Rule | 60,925 |
| 9 | Groundwater Rule | 53,827 |
| 10 | Fluoride | 35,736 |
| 11 | Gross Alpha, Excl. Radon and U | 34,296 |
| 12 | Interim Enhanced Surface Water Treatment Rule | 29,055 |
How It Works
Search Water Systems
Browse 433,347 public water systems by state, type, or name. Each system includes its EPA identifier, population served, and water source type.
Review Violations
Check 12,049,741 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. 1,632,684 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 433,347 water systems across 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 1,632,684 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.