Stormwater Management Program

June 2022: City Council adopted the 2019 Stormwater Management Manual of Western Washington for all future development, re-development, and construction projects effective June 30, 2022.

Permits issued by the City after June 30 shall be for project designed, reviewed, and constructed in accordance with BIMC 15.20 and the 2019 SWMMWW.


City of Bainbridge Island’s stormwater management program is a set of actions and activities designed to reduce the discharge of pollutants into water resources to protect water quality for human benefit.

Stormwater is the rain and melted snow/ice that falls onto built and natural landscapes and flows off rooftops, streets, and other surfaces. These surfaces can have pollutants on them such as pet waste, dirt, litter, yard waste, automotive fluids, chemicals, soaps, etc. that meet the stormwater as it makes its way into the ground or into lakes, rivers, and other water bodies. This is stormwater runoff and is the largest cause of water pollution in the world.


The City is required by the State of Washington Department of Ecology to have a Stormwater Management Program in place. This requirement is a condition of the City’s National Pollutant Discharge Elimination System (NPDES) Western Washington Phase II Municipal Stormwater Permit which is required for the City to continue to operate its Small Municipal Separate Storm Sewer (MS4) that discharges into island water bodies and Puget Sound. The City’s MS4 is operated and maintained by the Public Works Department. See links below for more information on National Pollutant Discharge Elimination System (NPDES):

Annually, the City reports to the Department of Ecology on the progress of the previous year’s Stormwater Management Program and provides an updated Plan for the coming year. Both documents are available for review here as well as upon request. Please submit your comments and/or concerns to the NPDES Permit Coordinator.

As required by the current 2019-2024 NPDES Permit, the City of Bainbridge Island’s Stormwater Management Program work addresses the following major components of stormwater management in Western Washington:

  • Stormwater Planning. 
  • Public Education and Outreach
  • Public Involvement and Participation 
  • Municipal Separate Storm Sewer System (MS4) Mapping and Documentation. 
  • Illicit Discharge Detection and Elimination 
  • Controlling Runoff from New Development, Redevelopment, and Construction Sites
  • Operations and Maintenance 
  • Source Control Program for Existing Development