Stormwater Discharges
Stormwater Discharges From Municipal Separate Storm Sewer Systems (MS4s)
Under the NPDES storm water program, operators of large, medium and regulated small municipal separate storm sewer systems (MS4s) require authorization to discharge pollutants under an NPDES permit.
Medium and large MS4 operators are required to submit comprehensive permit applications and are issued individual permits. 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.
Specific NPDES permit requirements for MS4s can be found through the links provided below
- NPDES Permit Requirements for MEDIUM and LARGE MS4s
- NPDES Permit Requirements for Regulated SMALL MS4s
