Does Information Disclosure Reduce Drinking Water Violations in the United States?

The 1996 Safe Drinking Water Act Amendments required community water systems to disclose violations of drinking water standards to their customers in annual water quality reports. We explore the impact of three methods of disclosure on health-based drinking water quality violations using a matching and differences-in-differences framework with a national data set of drinking water quality violations from 1990 to 2001. We find that this information disclosure requirement reduced drinking water violations significantly and that the primary effect of disclosure on violations persists for at least four years after policy implementation. We find no evidence, however, that water systems trade these potentially more salient violation reductions for potentially less salient reductions in violations of other standards, nor do we find any evidence that water systems responded differentially to disclosure based on the demographic or political characteristics of their customers.