Storm Water and Municipal Separate Storm Sewer Systems (MS4s)

Permits required for the discharge of storm water from small, medium, and large systems. Phase I and Phase II requirements. Waivers for qualified small systems.

Municipal Separate Storm Sewer System (MS4) Discharges: Am I Regulated? Explains which MS4s are required to obtain permit coverage for their storm water discharges.

Topics Under This Category:

	General Permit TXR040000 for Phase II (Small) MS4s Requirements and steps necessary to obtain authorization for storm water discharges from small MS4s.
	Storm Water Permitting Requirements for Medium and Large (Phase I ) MS4s Explains the requirements and steps for applying for a permit to authorize storm water discharges from Phase I (medium and large) MS4s as well as annual reporting and discharge monitoring report requirements.
	Storm Water Permitting Requirements for Phase II (Small) MS4s Authorization options, control measures required, annual reporting requirements, and links to best management practices for operators of Phase II MS4s.
	Waiver Option 1 from MS4 Permitting Requirements (Small Systems Only) Explains the waiver from the permitting requirement available to small MS4s which serve a population of less than 1,000.
	Waiver Option 2 from MS4 Permitting Requirements (Small Systems Only) Explains the waiver from the permitting requirement available to small MS4s which serve a population of less than 10,000.