A new study reveals that nearly a third of people in the United States—around 97 million residents—are exposed to harmful, unregulated chemicals in their drinking water.
The study, conducted by scientists at Silent Spring Institute and published in Environmental Health Perspectives, highlights significant concerns about water quality and its unequal impact on different communities.
Dangerous chemicals in water
The U.S. Safe Drinking Water Act regulates around 100 contaminants, requiring public water systems to test for them and take action if levels are too high.
However, thousands of other harmful chemicals are not regulated, meaning they can still end up in drinking water.
According to the study, many unregulated contaminants have been detected in water supplies, including:
- 1,4-dioxane: A probable cancer-causing chemical used in consumer products and solvents.
- PFAS: Also known as “forever chemicals,” these are used in non-stick coatings and are linked to cancer, thyroid disease, and other health issues.
- Chlorodifluoromethane (Freon 22): A refrigerant linked to ozone depletion.
- 1,1-dichloroethane: A solvent used in paints and plastics that is associated with cancer.
These chemicals were found in 27% of water systems serving millions of Americans.
Communities of color hit hardest
The study found that Hispanic and Black residents are more likely to have unsafe levels of unregulated contaminants in their water.
These communities are often located near sources of pollution, such as industrial sites, airports, military bases, and wastewater plants, which release harmful chemicals into water supplies.
Lead author Aaron Maruzzo explained that racial disparities in water quality are not fully explained by income or socioeconomic status. Historical factors like systemic racism and redlining—the practice of segregating neighborhoods and placing industrial facilities in communities of color—have contributed to these inequities.
Nitrate and PFAS: Ongoing concerns
This study builds on earlier research by Silent Spring Institute, which showed that Hispanic communities are more likely to have higher levels of nitrates in their drinking water. While the Environmental Protection Agency (EPA) set limits on nitrate decades ago to protect infants from “blue baby syndrome,” new research suggests even lower levels can increase the risk of colorectal and bladder cancer.
Similarly, a 2023 study co-authored by Silent Spring scientists found that water systems in areas with higher Hispanic and Black populations had more PFAS contamination. Recent testing shows PFAS contamination is even more widespread than previously thought, meaning the actual number of affected residents may be higher than estimated.
Calls for action
In April 2024, the EPA introduced drinking water standards for six PFAS chemicals. However, the study’s authors argue that more needs to be done. They emphasize the need for stricter regulations on unregulated contaminants and better protection of source water from pollution.
“We need to reduce discharges of pollutants into water supplies and provide more resources for communities of color to address these challenges,” said Laurel Schaider, a senior scientist at Silent Spring Institute.
This research highlights the urgent need for fairer policies and stronger protections to ensure clean, safe drinking water for everyone in the U.S.
