US Water Quality Maps
Visualize drinking water contamination across every US state. Explore PFAS levels, lead contamination, and violation records to see how your state compares.
Explore by contaminant
Dive deeper into specific contaminant data with dedicated maps, state rankings, and context about health risks and EPA regulations.
How we calculate state grades
Each city receives a score from 0-100 based on four pillars: violations (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). State averages are population-weighted and reflect the most recent EPA data available.
Data sources
Our maps draw from three EPA databases: the Safe Drinking Water Information System (SDWIS) for violations, the Lead and Copper Rule (LCR) testing results, and the fifth Unregulated Contaminant Monitoring Rule (UCMR 5) for PFAS data collected 2020-2023.
Understanding the maps
Darker colors indicate worse contamination or lower scores. States shown in gray have insufficient data for that particular contaminant. Click any state to view a detailed breakdown including city-level data, historical trends, and specific contaminant levels. You can also search for your specific city on our homepage.
Check your city's water quality
Get a detailed grade for your city's drinking water, including contaminant levels and personalized safety recommendations.
Search your city