Linking Drinking Water Violations to Public Health: A Statewide Analysis of Emergency Department Visits for Waterborne Diseases

Ensuring safe drinking water remains a critical public health concern in the United States, where many community water systems (CWSs) experience regulatory noncompliance with drinking water standards that are designed to protect public health. The Safe Drinking Water Act establishes a regulatory framework with enforceable standards for a variety of water quality constituents. While health-based (HB) violations are commonly used as indicators of waterborne disease risk, there is a lack of studies directly linking these violations to health outcomes. This study addresses this gap by examining the association between HB and nonhealth-based (NHB) violations in CWSs and emergency department visits (EDVs) for gastrointestinal illnesses across Texas from 2016 to 2022. Using Poisson regression, we evaluate these associations while adjusting for system characteristics (e.g., size, ownership, population served) and socio-demographic indicators (e.g., Social Vulnerability Index (SVI) and percent urban population). Results show that both HB and NHB violations are positively associated with EDV rates, and these associations remain significant after accounting for system and sociodemographic factors. To address how spatial misalignment of health and violations data impacts model estimates, we apply a bootstrap approach that confirms the statistical significance of HB violations, source water type, population density, SVI, and urban population. This study represents an important step toward evaluating service-area-level associations between regulatory water quality violations and public health outcomes and highlights the importance of improved data quality and more refined health risk indicators. As the first study to examine associations between drinking water violations and EDV rates at the CWS service-area level, our findings offer critical insights that inform future research and guide the development of more effective regulatory and public health interventions.