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General Permit, Forms, & FAQs

Final 2023 MS4 General Permit

The Agency re-issued the MS4 General Permit on September 28, 2023.  The MS4s will need to submit an NOI form by November 27, 2023 (60 days from permit issuance) and a complete SWMP with current PCP and FRP(s) by March 26, 2024 (180 days from permit issuance). 

Application Documents

Assistance Documents

Annual Report - Due April 1

  • Annual Report Form - (updated 2/26/2024) A complete Annual Report for the 2023 calendar year consists of the Annual Report Form, the Annual Report Workbook, and the BMP Tracking Table. 
  • Annual Report Workbook (updated 2/26/2024)
  • BMP Tracking Table (updated 3/13/2020) - latest change only affects practices with <0.1" of storage depth. If you have any questions or issues with the table, please contact Emily Schelley.

Past Permit, Presentations, and Forms

To submit your MS4's REI, first upload the data to the MRGP Implementation Table.  Once it has been uploaded, complete the REI Submittal Form and submit both the form and the MS4's complete SWMP to the Stormwater Program.  Submittal of the REI requires a permit amendment, so the complete application will be placed on public notice for 30 days.  At the end of that period, when the application has been reviewed and any comments have been addressed, the MS4 will receive an amended permit authorization.  There is no fee associated with this amendment.  

  • REI Guidance & Implementation Table - available on MRGP website

Frequently Asked Questions

Frequently Asked Questions and Guidance

MS4 Baseload and Reduction Target Calculations
Catch Basin Outlet Interim Methodology
MS4 Operational Tracking and Accounting Interim SOP

Stormwater Impaired Waters Flow Monitoring