What grade is your tap water?
Independent water quality ratings for thousands of US public water systems. Search by city, ZIP, or utility name.
Transparent scoring
Every grade is calculated from public EPA and EWG data using a published, weighted formula. No black boxes.
Health-guideline based
We compare contaminant levels against EWG's health-based guidelines, not just bare-minimum legal limits.
Filter recommendations
Each utility page recommends specific filters matched to that water's actual contaminants — not generic advice.
The state of US drinking water
Why these grades exist
Federal water quality standards have not been meaningfully updated in decades. Most US drinking water is technically legal yet still contains contaminants at levels modern science considers unsafe — PFAS, lead, disinfection byproducts, radium, and more. TapWaterSafety exists to make that gap visible to the people drinking the water.
Our scoring methodology is fully public. Our data comes from the EPA, the Environmental Working Group, and utilities' own Consumer Confidence Reports. We are not affiliated with any utility, government agency, or filter company — though we do earn affiliate commissions when readers buy filters through our recommendations (which never influences our scores).