Who is Regulated under Phase II?
Municipalities are automatically designated if their small municipal separate storm sewer system (MS4) is located either completely or partially within an urbanized area (UA) or densely populated area (DPA)
Federal, State, and Quasi-State facilities serving an average daily population of equal to or greater than 1,000 persons regardless of location
Department of Transportation (DOT) MS4s in UAs, DPAs, and areas qualifying as divided highways
MS4s designated on a case by case basis