New York City’s Municipal Separate Storm Sewer System (MS4) Stormwater Management Program is a multiagency effort led by the Department of Environmental Protection (DEP) to reduce pollution in stormwater runoff in the MS4 Area of NYC. This MS4 Map represents the known MS4 outfalls and drainage areas as of August 1, 2020 and provides additional data relevant to the MS4 Permit. The MS4 map only shows areas draining to the Municipal Separate Storm Sewer System. DEP also maintains combined sewer and sanitary sewer systems; these service area delineations are not represented on this map. More information about the MS4 Stormwater Management Program is available at www.nyc.gov/dep/ms4

Retired September 28, 2023. District MS4 Sewershed drainage areas. The dataset contains locations and attributes of the drainage areas of MS4 outfalls created as part of the DC Geographic Information System (DC GIS) for the D.C. Office of the Chief Technology Officer (OCTO) and participating D.C. government agencies. A database provided by WASA identified outfalls, drainage structures, and MS4 outfall locations. All DC GIS data is stored and exported in Maryland State Plane coordinates NAD 83 meters.

The dataset contains the boundaries of the MS4 general permit, which are defined as the intersection of US Census urbanized areas and the watershed boundaries of the stormwater-impaired waters with approved TMDLs.

Special Condition S8.D of the 2007-2012 Phase I Municipal Stormwater Permit required permittees to collect and analyze data to evaluate pollutant loadings of stormwater discharged from different land uses: high density (HD) residential, low density (LD) residential, commercial, and industrial. To meet the S8.D requirement, Phase I Permittees collected water quality and flow data, sediment data, and toxicity information from stormwater discharges during storm events.

,Every year, the District submits an Annual Municipal Separate Storm Sewer System (MS4) Report to the U.S. Environmental Protection Agency (EPA), documenting the activities that fulfill the requirements of the District’s National Pollutant Discharge Elimination System (NPDES) MS4 permit. The NPDES permit program, authorized by the federal Clean Water Act and managed by the EPA, addresses water pollution by regulating point sources that discharge pollutants to waters of the United States. Activities under the permit include, for example, implementation of stormwater management practices and water quality monitoring. This story map summarizes these activities and is a regulatory requirement under the permit.,MS4 is an acronym that stands for Municipal Separate Storm Sewer System. The MS4 collects and conveys stormwater from streets, sidewalks, and rooftops to nearby waterways through stormwater sewers and outfalls. In the District of Columbia, the MS4 area is located along the outer edges of the city and surrounds the combined sewer system (CSS) area that serves the inner portions of the city. The MS4 area is different from the CSS area in that it does not convey sanitary sewage. Stormwater from the CSS area is either conveyed to the Blue Plains Wastewater Treatment Plant or discharged at combined sewer outfalls. DC Water’s Clean Rivers Program is dedicated to reducing combined sewer overflows into the District’s waterways.,Several areas in the District are not part of either the MS4 or CSS. Most District parkland falls within this “Direct Drainage” category, and stormwater from these areas naturally drain to nearby waterways following the local topography.,Learn more about why the MS4 is important to the District's waterways in this Story Map collection.,,

,Every year, the District submits an Annual Municipal Separate Storm Sewer System (MS4) Report to the U.S. Environmental Protection Agency (EPA), documenting the activities that fulfill the requirements of the District’s National Pollutant Discharge Elimination System (NPDES) MS4 permit. The NPDES permit program, authorized by the federal Clean Water Act and managed by the EPA, addresses water pollution by regulating point sources that discharge pollutants to waters of the United States. Activities under the permit include, for example, implementation of stormwater management practices and water quality monitoring. This story map summarizes these activities and is a regulatory requirement under the permit.,MS4 is an acronym that stands for Municipal Separate Storm Sewer System. The MS4 collects and conveys stormwater from streets, sidewalks, and rooftops to nearby waterways through stormwater sewers and outfalls. In the District of Columbia, the MS4 area is located along the outer edges of the city and surrounds the combined sewer system (CSS) area that serves the inner portions of the city. The MS4 area is different from the CSS area in that it does not convey sanitary sewage. Stormwater from the CSS area is either conveyed to the Blue Plains Wastewater Treatment Plant or discharged at combined sewer outfalls. DC Water’s Clean Rivers Program is dedicated to reducing combined sewer overflows into the District’s waterways.,Several areas in the District are not part of either the MS4 or CSS. Most District parkland falls within this “Direct Drainage” category, and stormwater from these areas naturally drain to nearby waterways following the local topography.,Learn more about why the MS4 is important to the District's waterways in this Story Map collection.,,

This geospatial dataset depicts a sewage no-discharge zone established under Clean Water Act Section 312. The area(s) depicted are zones where the discharge of any sewage, treated or untreated, from vessels is prohibited. This layer was created using information from the corresponding Federal Register notice and is created for informational purposes, not to be used for enforcement.

This geospatial dataset depicts a sewage no-discharge zone established under Clean Water Act Section 312. The area(s) depicted are zones where the discharge of any sewage, treated or untreated, from vessels is prohibited. This layer was created using information from the corresponding Federal Register notice and is created for informational purposes, not to be used for enforcement.

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