The Clean Water Act (CWA) requires that the U.S. Environmental Protection Agency (EPA) limit discharges to the nation’s water to only those permitted pursuant to the National Pollutant Discharge Elimination System (NPDES). EPA can delegate to states the authority to administer the NDPES program. See 33 U.S.C. § 1342(b). Although EPA has delegated its NPDES permitting authority to forty-six states and the U.S. Virgin Islands, several recent petitions ask EPA to withdraw this delegated authority.