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Construction Site

Construction and Post-Construction Program

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 and Post-Construction (C/PC) stormwater permits.

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

C/PC Criteria

Any development or redevelopment project (public or private) will require C/PC stormwater 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 NYC municipal operations and facilities where stormwater drains from the project directly to surface waters are also considered to be in the MS4 area.


  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 C/PC stormwater permits from DEP.

Determining Drainage and 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.

C/PC Program Resources