Bureau of Economic Geology

Assessing Linkages between Drinking Water Quality Violations and Social Vulnerability in the United States

January 7, 2022 9:00 AM


Bridget R. Scanlon, Ph.D.
Senior Research Scientist
Bureau of Economic Geology
Jackson School of Geosciences
The University of Texas at Austin


Increasing concern over our drinking water supplies, particularly in socially vulnerable communities, has prompted government initiatives to increase compliance and provide safe drinking water for all. Here we evaluated health-based violations of the Safe Drinking Water Act in community water systems across the US to decipher spatiotemporal relationships between violations and social drivers. We show that water quality violations are strongly linked to social vulnerability in the Southwest US (e.g., arsenic, radionuclides, and nitrate) and Southcentral US (disinfection byproducts) where violations and social vulnerability are both high and in the Midwest where both are low. However, violations are generally not linked to social vulnerability in the Southeast (low violations, high social vulnerability) and in the Northeast (high violations, low social vulnerability). Texas ranked first in terms of EPA serious violators and in number of community water systems with any health-based violations. Approximately 100 times more people experience both high levels of any drinking water violation and high social vulnerability (~12 million people) relative to populations with low violations and social vulnerability. Of all social vulnerability metrics, poverty and minority status exhibited the strongest linkages to violation incidence. Notably, persistence of violations over time is strongly linked to social vulnerability (R2: 0.62–0.83) across the US, indicating much greater challenges for socially vulnerable communities to attain and maintain system compliance. These water quality challenges and associated environmental justice issues are likely exacerbated by climatic factors. Understanding spatiotemporal variability in noncompliance can help guide deployment of new infrastructure funding to address health-based violations which disproportionately persist in socially vulnerable populations served by very small to small community water systems in mostly rural settings.

Bridget Scanlon is a Senior Research Scients at the Bureau of Economic Geology, Jackscon School of Geosciences, Univ. of Texas at Austin. Her current research focuses on water quality issues related to EPA regulations and linkages to social vulnerabilty throughout the U.S., with particular emphasis in Texas. This study should help guide water infrastructure funding to improve compliance with EPA regulations. She has (co)authored ~160 publications. Dr. Scanlon is a member of the National Academy of Engineering.

Bridget Scanlon

University of Texas at Austin

University of Texas

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