Annual Reports


Each MS4 must submit an Annual Report indicating progress on implementing their stormwater management plan. CT DEEP strongly recommends using these templates but alternate formats will be accepted as long as all the required information is provided.

We have tried to streamline the annual report template this year based on feedback from DEEP on what they need and from towns on the need to simplify. Nothing dramatic, but hopefully an improvement. Note that you can still use your original template and just update with the new information on your activities if you prefer. The guidance document below indicates what changes were made.

  • The 2023 Streamlined Annual Report template can be accessed here.

    • Please note for this 2023 report: To receive credit for activities completed during the lapse in permit coverage, include those activities in this report. DEEP has stated that for enforcement, the focus will be on any violations of the permit which existed before the original expiration date on June 30th, 2022, rather than any lapses that occurred between then and October 1st, 2023 (when the permit was reissued). However, DEEP will be providing credit for any work
      which was completed between the timeframe of June 30th, 2022 and October 1st, 2023.
  • Download the Guide to changes to the Streamlined Annual Report here. Please note, these changes were made to the 2021 Annual Report. No recent changes have been made to the Streamlined Annual Report template.

Submission timeline

  1. January 31st - Notify the public when the Annual Report and stormwater management plan will be made available for review and who to contact to provide comments. More details can be found on page 21 of the general MS4 permit. Providing notice earlier than January 31st is encouraged.
  2. February 15th - Post the Annual Report and current stormwater management plan to the town or institution website (see page 16 of permit for details). Also have hardcopies of the report and plan available at town hall or a public library.
  3. April 1st - Submit the Annual Report to DEEP (see page 45 of permit for details). Mail the review fee which is $375 for institutions and $187.50 for municipalities and the Annual Report transmittal form (download here) to CT DEEP Central Permit Processing Unit and email an electronic copy of the Annual Report to

Reporting Software

In the past, MS4 communities were able to use a software called Assist to manage compliance with the MS4 permit and produce annual reports. That program is unfortunately no longer supported by the company. However, there are other companies that offer similar programs.

Examples of some of these programs include: