Ky DOW Municipal Separate Storm Sewer Systems (MS4)

Medium and large Municipal Separate Storm Sewer Systems (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. Under the NPDES stormwater program, operators of large, medium and regulated small municipal separate storm sewer systems (MS4s) require authorization to discharge pollutants under an NPDES permit. Download spatial layer from Box.