Municipal Separate Storm Sewer System

MS4 Construction Permits

Certain new and redevelopment projects located in New York City that involve or result in a soil disturbance within the municipal separate storm sewer system (MS4) area are required to apply for construction permits.

Projects that meet the criteria must submit permit applications to DEP. DEP will review and approve applications, and inspect construction activities for stormwater impacts and post-construction stormwater management practices.

Download the Stormwater Design Manual as a reference for use when complying with program rules.

Stormwater Permitting & Tracking System

To apply for MS4 construction permits, you must submit an application using our Stormwater Permitting and Tracking System or “SWPTS.”

Access SWPTS

Once you login to SWPTS, the system will walk you through the various steps of the permitting process. For your application, you will need to have completed your Stormwater Pollution Prevention Plan (SWPPP). Please refer to our SWTPS User Manual, the SWPPP Template, and the No Net Increase Calculator for additional guidance:

MS4 Construction Permits Criteria

Any development or redevelopment project (public or private) will require MS4 construction permits if:

  1. It contributes stormwater runoff to the MS4 area. A project is in the MS4 area* if stormwater drains from the project to surface waters via:
    • separate storm sewers owned or operated by NYC
    • combined sewer overflow (CSO) outfalls downstream of a CSO regulator (a device used in NYC’s combined sewers to control the diversion of sewage flow to the treatment plants during dry and wet weather)
    • high-level storm sewers and Bluebelts
  2. *Projects involving New York City municipal operations and facilities where stormwater drains from the project directly to surface waters are also considered to be in the MS4 area.

    AND

  3. It involves construction activity that results in one acre or more of land disturbance. This includes disturbances of less than one acre that are part of a larger common plan of development, or sale that will ultimately disturb one or more acres of soil.

All projects that meet both of the above criteria are required to obtain MS4 construction permits from DEP.

Determining Drainage & MS4 Area Boundaries

Please use our Records Request Form to determine if stormwater drains from your project into to the MS4 area.

Our interactive MS4 map can help you determine into which waterbody your project discharges runoff.

MS4 Construction Permits Resources

MS4 Construction Permits Contact

If you have additional questions regarding the permitting process, please email ms4construction@dep.nyc.gov, with MS4 Construction Permits in the subject line.