Effective June 1, 2019, New York City is required to administer the Municipal Separate Storm Sewer Permit (MS4) for the NYC Department of Environmental Conservation (DEC). The NYC Department of Environmental Protection (DEP) is responsible for administering the permit and collecting all documentation for the compliance. All relevant projects are to be reviewed at the start of design to see if they are within this MS4 area.
The MS4 Construction and Post Construction Fact Sheet MS4 Construction and Post Construction Fact Sheet provides a quick reference of the history behind the permit and what is required.
The DEP's Municipal Separate Storm Sewer System webpage has detailed information with links to reference material. The webpage also includes an interactive map of the MS4 drainage area to be used to determine if a project is within the permit area. If a project site is near the MS4 area, designers are to submit a water-sewer request form , as the MS4 area is being actively increased and the map may not have been updated.
During the scoping phase, all projects that potentially affect stormwater quality are required to perform a Green Infrastructure Assessment. Besides new construction and other projects that disturb land, roof replacements and repaving projects also trigger this requirement. The SCA has created Green Infrastructure Assessment Report templates for both Capacity and CIP projects. In addition, a Green Infrastructure Assessment Flow Chart of the process for determining if green infrastructure (not inclusive of green roofs) is technically feasible can be used by designers to help in determining the feasibility. This flow chart is based on DEP guidelines and is currently in draft form. The SCA will review the assessment reports and make the determination on implementation.
In addition to the ongoing maintenance requirements of the MS4 Permit by the Department of Education, all Contractors must follow the requirements of the MS4 Permit. Besides following Stormwater Pollution Prevention Plans and Sediment and Erosion Control to prevent soils from entering the system, Contractors must follow and implement measures to meet the pollution prevention and good housekeeping (PP/GH) requirements of the permit. Chapter 7 of NYC Stormwater Management Plan highlights the items that need to be addressed. Further, the DEP has created single page guidance documents of typical construction activities that would require PP/GH to be implemented with references to the applicable portions of the permit. These documents can be accessed on the Pollution Prevention/Good HousekeepingPollution Prevention/Good Housekeeping page.