Disparities in drinking water compliance: Implications for incorporating equity into regulatory practices

Disparities in drinking water quality pose harm to public health across the United States. Yet, few studies have systematically analyzed disproportionate exposure to impaired drinking water. This study sheds light on disparities in health-based drinking water violations and the shortcomings of regulatory assessment that only considers equity in terms of variation in compliance across system size. We examine the relationship between health-based violations, utility size, and socioeconomic factors, using probit regression and a balanced panel dataset of 1693 community water systems in California from 2000 to 2018. Demographics of water systems are developed using areal weighting. We find evidence of water equity concerns. Violation rates are several times higher at systems serving low-income areas and communities of color. These disparities are present even in models stratified by size of service population. Our findings highlight that equity in environmental regulation could be improved by considering factors beyond system scale.