California Attorney General Xavier Becerra, as part of a coalition of 16 states and four state environmental agencies, last Friday filed a comment letter warning the U.S. Environmental Protection Agency (EPA) that any attempt to roll back state oversight of federal projects under Section 401 of the Clean Water Act (CWA) would be unlawful. The letter responds to the EPA’s request for recommendations to revise existing guidance and regulations implementing Section 401. The statute preserves states’ authority to protect the quality of the waters within their borders.