Our Mission
Clean Water Index exists to make EPA drinking water compliance data easy to understand. Every public water system in the United States is required to meet safety standards set by the EPA under the Safe Drinking Water Act. When systems fail to meet these standards, violations are recorded in a federal database. We take that data and make it searchable by state and city.
Where the Data Comes From
All data on this site comes from the EPA Safe Drinking Water Information System (SDWIS), accessed through the EPA's Envirofacts API. SDWIS is the federal database that tracks compliance of public water systems with National Primary Drinking Water Regulations.
We include data for active community water systems (CWS) serving 100 or more people. Community water systems are those that serve the same population year-round, such as municipal water utilities.
Understanding Violations
Not all drinking water violations are the same. There are two main categories:
Health-Based Violations
These are the most serious type. A health-based violation means a regulated contaminant was found above the Maximum Contaminant Level (MCL) set by the EPA, or a required treatment technique was not properly applied. Contaminants can include bacteria, lead, nitrates, disinfection byproducts, and many other substances.
Monitoring & Reporting Violations
These violations mean a water system failed to collect samples, test for required contaminants, or submit results on time. While these don't necessarily indicate unsafe water, they do mean the system isn't being properly monitored — which could mask actual contamination.
What This Data Does Not Tell You
This data has important limitations you should understand:
- Historical record: Violation data includes the full historical record. A city with many violations may have resolved its water quality issues years ago.
- Private wells: SDWIS only covers public water systems. If you use a private well, this data does not apply to you.
- Current water quality: This site shows compliance violations, not real-time water quality measurements. Your water may contain contaminants below MCL levels that are still present.
- All contaminants: The EPA regulates about 90 contaminants. There are thousands of other substances that may be present in water but are not currently regulated.
Protecting Your Drinking Water
If you're concerned about your water quality:
- Request your water system's annual Consumer Confidence Report (CCR), which details exactly what's in your water
- Consider having your water independently tested by a certified laboratory
- Use an NSF-certified water filter appropriate for the contaminants of concern in your area
- Contact your local water utility directly for the most current information
Contact
Clean Water Index is an independent informational resource. We are not affiliated with or endorsed by the EPA or any government agency. For questions about this site, contact us at [email protected].
Data Sources
EPA Safe Drinking Water Information System (SDWIS) via the Envirofacts API. Community water systems serving 100+ people.