In what may be its first opportunity to test the waters of federal agency influence after the fall of Chevron deference, on October 16, 2024, the Supreme Court heard arguments in City and County of San Francisco v. Environmental Protection Agency. This case comes to the Court after a divided Ninth Circuit panel rejected a challenge to the EPA’s authority to enforce the Clean Water Act (“CWA” or the “Act”), 33 U.S.C. § 1251 et seq., through “general narrative prohibitions” spelled out in permits issued under the EPA’s National Pollutant Discharge Elimination System (“NPDES”) permitting program.