State-level regulation of disinfection byproducts in the United States

ABSTRACT Disinfection byproducts (DBPs), residual compounds formed from the chemical disinfection of drinking water, can cause a host of damaging public health and environmental impacts. This study evaluates the landscape of regulations designed to reduce the occurrence and/or impact of DBPs, focusing on regulations issued by the US states. Drawing on a systematic search of state administrative codes and agency websites, we first identify the presence, absence, and layering of DBP-related regulations. We then evaluate the number and types of policy tools – the specific approaches required by each regulation, such as monitoring requirements, economic incentives, and required treatment technologies – to identify how DBPs are being managed and how states cluster with relatively more and less robust regulatory frameworks. Finally, we evaluate the relationship between the regulatory approach and the frequency of drinking water quality violations for DBP compounds. While most states have at least one DBP-specific regulation, these vary substantially in their comprehensiveness. The most-used policy tools (monitoring, compliance schedules, and reporting) directly reflect federal regulations; few states have adopted innovative tools such as collaboration or financial incentives. We observe no relationship between regulatory efforts and water quality violations, suggesting that current policy implementation may not adequately address the complex risk of DBPs.