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Every community water system, with who it serves.
All 48,790 active community water systems in the 50 states and D.C., the systems that supply homes year round, from big-city utilities to mobile home parks, with the people and connections they serve, the counties and cities they serve, water source, ownership, and counts of health-based violations.
- Rows
- 48,790
- Columns
- 18
- Formats
- CSV, JSON, XML
As of: EPA Safe Drinking Water Information System, third quarter of 2026. The EPA refreshes its national download every quarter.
Preview
A few real rows
| Name | StateCode | PopulationServed | PrimarySource | Ownership | HealthViolations5Years |
|---|---|---|---|---|---|
| NEW YORK CITY SYSTEM | NY | 8271000 | Surface water | Local government | 0 |
| LOS ANGELES-CITY, DEPT. OF WATER & POWER | CA | 3875566 | Surface water | Local government | 0 |
| CITY OF HOUSTON | TX | 2970543 | Surface water | Local government | 1 |
| CHICAGO | IL | 2721308 | Surface water | Local government | 0 |
| SAN ANTONIO WATER SYSTEM | TX | 2643729 | Surface water purchased | Local government | 0 |
| MWRA | MA | 2580000 | Surface water | State or Territorial Government | 0 |
| MDWASA - MAIN SYSTEM | FL | 2377460 | Ground water | Local government | 0 |
| WASHINGTON SUBURBAN SANITARY COMMISSION | MD | 1900000 | Surface water | Local government | 0 |
Field guide
What's in each row
The system
EPA water system ID, name, state, and the agency that oversees it.
PWSID Name StateCode Regulator
Who it serves
Counties and cities served, the main kind of area served, people and service connections served, and the EPA size category.
CountiesServed CitiesServed ServiceArea PopulationServed ServiceConnections SystemSize
Source and ownership
Main water source, owner type, whether it sells water to other systems, and when it was first reported.
PrimarySource Ownership IsWholesaler FirstReported
Health-based violations
How many began in the last five years, how many are still open, and the date the most recent one began.
HealthViolations5Years OpenHealthViolations LastHealthViolation
Good to know
Before you use it
- Violations counted here are health-based only: a contaminant over its legal limit, a required treatment step not met, or a disinfectant level too high. Monitoring and reporting violations aren't counted.
- HealthViolations5Years counts violations that began on or after October 1, 2021. OpenHealthViolations counts those from any year that the state or EPA hasn't yet marked resolved.
- No violations doesn't certify that water is safe, and a violation doesn't mean the water is unsafe today. For a system's current water quality, see its annual Consumer Confidence Report or the state's drinking water program.
- SystemSize uses the EPA's categories by people served: very small (500 or fewer), small (501 to 3,300), medium (3,301 to 10,000), large (10,001 to 100,000) and very large (more than 100,000). CitiesServed is filled for about half of systems, because not every state reports it.
- 727 systems on tribal lands are overseen by the EPA or the Navajo Nation, as Regulator shows. Systems that serve people only part of the time or not at home, such as campgrounds, schools and businesses with their own wells, aren't included. Names are in capitals, as the EPA publishes them.
- In every format, dates are written as yyyy-MM-dd, and yes/no values as true or false. An empty value means nothing was recorded.
Where it comes in handy
What you can build with it
- Local information. Find the systems that serve a county or city.
- Research. Study water systems by size, source and ownership.
- Journalism. Report on systems with recent or unresolved health-based violations.
- Planning. Size up the utilities across a state.
Access
Try it free. Get all of it with a pass.
Free sample
- The water systems in Vermont
- A README with the field guide and source
Data Pass $69
- All 48,790 rows of U.S. drinking water systems
- One ZIP in CSV, JSON or XML, with a README
- Also every other collection and the whole dataset catalog, for 365 days
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