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Stay informed about common water contaminants affecting millions of Americans. Learn about health risks, EPA limits, and how to protect your family.
Click any contaminant to learn more about health effects, EPA limits, affected regions, and removal methods.
Health risks: Brain damage, developmental delays
Common in: Older homes, Midwest cities
Health risks: Cancer, immune system damage
Common in: Industrial areas, military bases
Health risks: Cancer, cardiovascular disease
Common in: Southwest, agricultural regions
Health risks: Blue baby syndrome, thyroid issues
Common in: Agricultural areas, Midwest
Health risks: Cancer, allergic reactions
Common in: Industrial areas, California
Health risks: Immediate illness, GI distress
Common in: Rural areas, aging infrastructure
Health risks: Taste issues, byproduct formation
Common in: All municipal water systems
Health risks: Hormone disruption, cancer risk
Common in: Agricultural regions
Health risks: Dental/skeletal fluorosis at high levels
Common in: Fluoridated systems, natural deposits
Health risks: Hormone disruption, antibiotic resistance
Common in: Downstream of wastewater treatment
See which cities have the highest contamination levels for each contaminant. Browse rankings by overall contamination or by specific contaminants like lead, arsenic, and PFAS.
Top 50 cities with the most concerning overall water quality scores.
View RankingsView contamination risks for major US cities. See which contaminants have been detected, historical issues, and current water quality grades.
EPA maximum contaminant levels balance health with what's economically feasible. Many scientists argue limits should be lower, especially for lead and PFAS.
Infants, pregnant women, elderly, and immunocompromised individuals are more sensitive to contaminants even at levels below EPA limits.
Municipal testing doesn't capture contamination from your home's plumbing. Consider testing for lead if you have older pipes or fixtures.
The right water filter can remove most contaminants and give you peace of mind. See our recommendations based on your specific water quality issues.