October 18, 2022, marked the anniversary of the Clean Water Act (CWA), the primary federal law governing pollution control and quality of the waters of the United States. Though the Act has achieved vital successes, whether they can be sustained and how further progress can be made remain fundamental questions. On October 25, 2022, the Environmental Law Institute hosted a panel of experts at its 2022 Annual Policy Forum to evaluate the past 50 years of the CWA, while looking ahead to the next 50 years.

This Comment examines the legal framework for state protection of nonfederal waters and its implications for cooperative federalism. After a brief overview and legal background, it identifies some recent state actions that attempt to fill gaps in coverage created by changes in federal interpretations of the Clean Water Act. It then summarizes the current scope of state regulation of waters in every state, in order to discern the likely impact of changes at the federal level on the status of waters in the states.