The federal Clean Water Act (CWA) has been instrumental in restoring the health and safety of the nation’s bays, harbors, and beaches from industrial and municipal discharges during the past 40 years. But does the CWA now regulate Independence Day fireworks? According to some California regulators, the answer may be yes. Recently, the California Regional Water Quality Control Board for the San Diego Region has interpreted the CWA in an unprecedented fashion that threatens some of San Diego’s most cherished community traditions—and dramatically extends the regulatory scope of the CWA—with potential unintended and far-reaching consequences throughout the United States.