Probability of Exposure to Contaminated Drinking Water

According to EPA data, approximately 7% of community water systems in the United States have health-based violations in any given year, potentially affecting millions of people. A comprehensive study found that between 2004 and 2022, nearly 1 in 4 Americans were served by community water systems that violated the Safe Drinking Water Act at some point.

Common contaminants found in drinking water include lead (especially in older homes with lead service lines), PFAS ("forever chemicals," detected in about 45% of US tap water samples), arsenic, nitrates, disinfection byproducts, and microbial contaminants. The Flint, Michigan water crisis brought national attention to lead contamination, but similar issues exist in many communities across the country.

Rural communities and communities of color are disproportionately affected by water quality issues. About 2.2 million Americans lack access to running water or basic plumbing. Prevention measures include regular testing of home water, using certified water filters (NSF/ANSI certified), and staying informed about local water quality reports (required to be published annually by water utilities). The EPA's Maximum Contaminant Levels set legal limits for dozens of water pollutants.