Municipal Separate Storm Sewer System (MS4) General Permit Renewal
Municipal Separate Storm Sewer Systems (MS4s) consist of storm sewers, gutters, storm drain inlets, and similar features owned by cities, counties, and other government entities. These systems collect and discharge stormwater into local water bodies. The division regulates these point source discharges to state waters through permit requirements. MS4 Permits issued to qualifying municipalities require programs that help prevent pollutants in stormwater runoff from contaminating the MS4s.
The Water Quality Control Division will begin the process of renewing the MS4 general permit and the Cherry Creek Basin MS4 general permit next month. These meetings will be an opportunity for the division and stakeholders to discuss the proposed changes to the permit. At the end of this process, the division will consider stakeholder feedback and publish a draft permit for public comment. Following the public comment period, the division will respond to and incorporate comments into a final permit, where applicable.
To receive email notifications about this effort, please use this form and select “Permits - Non-Standard Stormwater” and/or “Permits - Standard Stormwater” from the menu.
How to get involved
The division will host a stakeholder engagement process beginning in July 2025 through May 2026.
Meeting materials will be located in this public folder.
Scheduled stakeholder meetings:
- Wednesday, July 30 | 2 to 4 p.m. (For new and potential new permittees.)
- Monday, Sept. 22 | 2 to 4 p.m.
- Thursday, Nov. 20 | 2 to 4 p.m.
- Thursday, Feb. 12, 2026 | 10 a.m. to noon.
- Thursday, April 2, 2026 | 10 a.m. to noon.
- Wednesday, May 20, 2026 | 10 a.m. to noon.
To learn more about MS4 permits, please visit this webpage. You can also view the following:
For questions or comments related to this stakeholder engagement webpage, email cdphe.commentswqcd@state.co.us.
For questions about the MS4 general permit, please email Mary Welch at mary.welch@state.co.us.