Compare Water Quality
Side-by-side comparisons of U.S. drinking water systems, states, and contaminants. See risk levels, violation counts, PFAS records, and treatment options together.
Water Utilities
Compare two public water systems: risk level, violations, PFAS records, population served, and primary contaminants.
States
Compare statewide water quality: violation rates, PFAS prevalence, high-risk and safest water systems.
Contaminants
Compare EPA limits, health effects, treatment options, and number of affected utilities for any two contaminants.
Utility Comparisons
New York City vs Chicago
Risk level, violations & PFAS records
Los Angeles vs Houston
Risk level, violations & PFAS records
Phoenix vs Las Vegas
Risk level, violations & PFAS records
Philadelphia vs Baltimore
Risk level, violations & PFAS records
Boston (MWRA) vs Washington DC (WSSC)
Risk level, violations & PFAS records
San Antonio vs Phoenix
Risk level, violations & PFAS records
Find any utility on its utility page and use the Compare button to run a custom comparison.
State Comparisons
California vs Texas
Water quality comparison
New York vs Florida
Water quality comparison
Ohio vs Michigan
Water quality comparison
Illinois vs Pennsylvania
Water quality comparison
Arizona vs Nevada
Water quality comparison
Washington vs Oregon
Water quality comparison
New Jersey vs Connecticut
Water quality comparison
North Carolina vs Virginia
Water quality comparison
Contaminant Comparisons
How Comparisons Work
Data Source
Violation and risk data comes from EPA SDWIS and UCMR 5 monitoring databases, covering all community water systems serving 25+ people.
Risk Levels
Risk is calculated from open health-based violations, contaminant severity, and population affected. Five tiers: Safe, Low, Moderate, High, Critical.
Limitations
Data reflects reported violations only. Unmonitored contaminants, private wells, and point-of-use conditions are not captured.