Stormwater Management Program

Compliance with SPDES Construction Permit Requirements

Construction activities that disturb an acre (43,560 square feet) or more of land and discharge to waters of the State are subject to regulation under the New York State Department of Environmental Conservation (NYSDEC) SPDES General Permit for Stormwater Discharges from Construction Activity, Permit No. GP-0-20-001. In order for a construction activity to gain coverage under GP-0-20-001, applicants must first prepare a Stormwater Pollution Prevention Plan (SWPPP) that meets NYSDEC standards and submit a Notice of Intent (NOI) to the agency. Additionally, if the construction activities will occur within one or more of the Town's SPDES Regulated Storm Sewersheds, the SWPPP must be submitted for review and acceptance by the Engineering Department prior to submitting the NOI to the NYSDEC. SWPPPs subject to review and acceptance by the Town will also constitute a Stormwater Management Control Plan (SMCP) for the construction activity as per Chapter 236 of the Town Code.

Please note that the location and extent of the regulated storm sewersheds will be continually updated based on new modeling, field observations and regulations promulgated by the NYSDEC. You should check this page prior to planning any new construction activity to ensure that you are basing your permit applications on the current version of the regulatory boundary map.

Planning Application Requirements

Site Plan and Subdivision Applications submitted to the Planning Department must include a complete SMCP as part of the application package. The SMCP will be forwarded to the Engineering Department for review. Upon determination that the plan meets the requirements of Chapter 236, the approved plan will become part of the Planning Board's Site Plan or Subdivision approval.

Please note that if the development action is subject to SPDES Construction Permit Requirements, the applicant must also provide a copy of the Notice of Intent submitted to the NYSDEC prior to receiving final Site Plan or Subdivision approval. 

Municipal SPDES Permit Requirements

The Town of Southold (Town) adopted a revised Stormwater Management Program Plan (SWMPP) on April 23, 2013. The SWMPP specifies the methods and measures used by the Town to achieve compliance with the NYSDEC SPDES General Permit for Stormwater Discharges from Municipal Separate Storm Sewer Systems (MS4s), Permit No. GP-0-15-003. This general permit requires the Town to comply with six Minimum Control Measures (MCMs). GP-0-15-003 regulates municipal activities within the Town's SPDES Regulated Storm Sewersheds.

The Town's 2023 Draft MS4 Annual Report is available for public review and comment. Questions or comments about the content of the annual report or the Town's overall Stormwater Management Program may be submitted via email to