SDWIS (Safe Drinking Water Information System)
The EPA database that tracks every public water system in the United States, violations, enforcement actions, contaminant levels, and system characteristics.
How It Works
SDWIS is the authoritative federal database for drinking water compliance. It contains records for over 150,000 public water systems, including their violation history, enforcement actions, contaminant monitoring results, and system details (population served, source type, treatment methods). States submit data to SDWIS as the primary regulators of drinking water under the Safe Drinking Water Act. IsWaterSafe uses SDWIS data as its primary data source. While SDWIS is publicly accessible through EPA's Enforcement and Compliance History Online (ECHO) tool, the raw data is difficult for consumers to navigate, which is why IsWaterSafe translates it into accessible Water Safety Scores and plain-language analysis.
Related Terms
- Consumer Confidence Report (CCR), An annual water quality report that every public water system must send to customers, showing which contaminants were detected, at what levels, and whether any violations occurred.
- Health-Based Violation, The most serious type of drinking water violation, indicating that water quality has exceeded a maximum contaminant level or failed to meet a treatment requirement that directly protects health.
- Environmental Protection Agency (EPA), The federal agency that sets drinking water standards, regulates public water systems, and publishes the data that IsWaterSafe uses to assess water safety.
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About This Definition
This definition is part of the IsWaterSafe Drinking Water Safety Glossary, 22 terms explaining water contaminants, treatment methods, and safety standards. Written for homeowners, renters, journalists, and public health professionals.