10,000+ reports checkedCheck my water →
STATE WATER QUALITY RANKINGS — 2025
Worst states for drinking water quality
Ranked using EPA violation records, PFAS monitoring data, and lead risk across 135+ cities. States are scored based on the proportion of their tracked cities rated "high concern" by EPA data — the more high-risk cities, the worse the state scores.
⚠️ Methodology note: Rankings reflect cities tracked by WaterCheckup — primarily larger population centers. Rural areas and smaller systems may have different profiles not captured here. Always check your specific ZIP code for the most accurate picture.
TOP 10 WORST STATES
#1
California
13 high-concern cities · 1 to monitor · 15 tracked total
Chromium-6 (hexavalent chromium)PFAS in some districtsDrought-driven water blending
Worst city: Glendale → view full report#2
Arizona
9 high-concern cities · 0 to monitor · 9 tracked total
High TDS / hard waterPFAS from military sitesArsenic in groundwater
Worst city: Tempe → view full report#3
Texas
5 high-concern cities · 10 to monitor · 15 tracked total
Disinfection byproducts (THMs)ChloraminePost-hurricane aging infrastructure
Worst city: McAllen → view full report#4
North Carolina
7 high-concern cities · 0 to monitor · 7 tracked total
GenX / PFAS contaminationDisinfection byproductsCatawba River contamination
Worst city: Cary → view full report#5
Florida
4 high-concern cities · 6 to monitor · 10 tracked total
PFAS contaminationSaltwater intrusionAging infrastructure
Worst city: West Palm Beach → view full report#6
Ohio
4 high-concern cities · 2 to monitor · 6 tracked total
Lead service linesLake Erie algal bloomsPFAS from industrial legacy
Worst city: Dayton → view full report#7
Colorado
2 high-concern cities · 3 to monitor · 5 tracked total
Lead service linesChloramine DBPsWildfire-impacted watershed
Worst city: Aurora → view full report#8
Michigan
3 high-concern cities · 0 to monitor · 3 tracked total
Lead service linesPFAS contaminationIndustrial legacy pollution
Worst city: Ann Arbor → view full report#9
Virginia
2 high-concern cities · 2 to monitor · 4 tracked total
James River contaminationDisinfection byproductsIndustrial legacy
Worst city: Norfolk → view full report#10
Nevada
2 high-concern cities · 1 to monitor · 3 tracked total
Extremely hard waterHigh TDSDisinfection byproducts
Worst city: Henderson → view full reportALL STATES — FULL RANKING
Check your exact water
State rankings show the big picture. Your specific water system may be better or worse than your state average. Enter your ZIP for the full picture.
Check My Water Free →RELATED RANKINGS