Water Quality Resources
Everything you need to understand, test, and improve your water.
Official Data Sources
These are the primary public databases we use and recommend for homeowners who want to dig deeper into their water quality data.
EPA
Safe Drinking Water Information System (SDWIS)
The federal database of every public water system, including violations and enforcement actions. Search by ZIP code or water system name.
The federal database of every public water system, including violations and enforcement actions. Search by ZIP code or water system name.
EWG
EWG Tap Water Database
A public tool that compares utility-reported contaminant levels against both legal limits and stricter health guidelines. Covers most US water systems.
A public tool that compares utility-reported contaminant levels against both legal limits and stricter health guidelines. Covers most US water systems.
USGS
USGS Water Hardness Map
Geological survey data showing regional hardness patterns based on bedrock type and groundwater chemistry.
Geological survey data showing regional hardness patterns based on bedrock type and groundwater chemistry.
Your Utility
Consumer Confidence Report (CCR)
Your utility's annual report with neighborhood-level data. Required by law. Contact your utility or search "[your city] water quality report" to find it.
Your utility's annual report with neighborhood-level data. Required by law. Contact your utility or search "[your city] water quality report" to find it.
CheckMyTap Tools
City Water Quality Search
Look up hardness, PFAS, lead, and other data for 1000 US cities.
System Comparisons
Side-by-side comparisons of water softeners, filters, and RO systems.
Water Quality Glossary
20 terms defined in plain language.
Our Methodology
How we collect, verify, and present water quality data.
Water Emergency Guide
What to do during boil-water advisories and contamination events.
Softener vs Filter Guide
Understand which type of system addresses your specific water issues.