Misha Vakoc,
Storm Water Permit Coordinator, NPDES Permits Unit,
Office of Water and Watersheds, US EPA Region 10

John Seigler,
Public Works Department, City of Pocatello

NPDES Permits for Municipal Separate Storm Sewer Systems (MS4)
The Stormwater Phase II Final Rule (December 8, 1999) requires operators of regulated small municipal separate storm sewer systems (MS4s) to obtain a National Pollutant Discharge Elimination System (NPDES) permit and develop a stormwater management program designed to prevent harmful pollutants from being washed by stormwater runoff into the MS4 (or from being dumped directly into the MS4) and then discharged from the MS4 into local waterbodies. Regulated small MS4 operators have the option of choosing to be covered by an individual permit, a general permit, or a modification of an existing Phase I MS4′s individual permit. In the MS4 program, operators are required to implement a stormwater management program as a means to control polluted discharges from these MS4s.