Can responsibility for nonpoint source runoff and third parties' stormwater discharges be imposed upon a local government under the Clean Water Act through an NPDES permit for discharges from its municipal separate storm sewer system?

QUESTIONS PRESENTED The State of Maryland is authorized by the United States Environmental Protection Agency to issue National Pollutant Discharge Elimination System (NPDES) permits under the Clean Water Act. The Maryland Department of the Environment issued an NPDES permit to Carroll County, Maryland to authorize stormwater discharges from the County’s municipal separate storm sewer system. Notwithstanding that NPDES permits regulate only point source discharges from the permitted facility, this NPDES permit makes the County responsible for nonpoint source runoff and other third-party stormwater discharges that neither flow into nor discharge from the County’s municipal separate storm sewer system. The questions presented are: 1. Can responsibility for nonpoint source runoff and third parties’ stormwater discharges be imposed upon a local government under the Clean Water Act through an NPDES permit for discharges from its municipal separate storm sewer system? 2. Is a Clean Water Act permitting decision to classify a “Small” municipal separate storm sewer system as “Medium” and subject it to the Clean Water Act’s heightened requirements for such systems without complying with the applicable designation process prescribed by 40 C.F.R. § 122.26(a) subject to judicial review?