Stormwater Management Program

Stormwater is the flow of water generated by precipitation and runoff from land, pavement, building rooftops and other surfaces. These surfaces, called impervious surfaces, do not allow the soil to absorb and filter the rain water. The run off from these surfaces carries pollutants including oil, grease, metals, and bacteria. The City of Bainbridge Island (COBI) drains stormwater directly to the Puget Sound, through its municipal separate stormwater system (ms4) or via various streams on the island. Ecology requires that COBI apply for and implement the Western Washington Phase II Municipal Stormwater Permit (the Phase II permit) in order to discharge stormwater to these water bodies.

Tree With Surface Water

This permit requires the (COBI) to develop and implement a Stormwater Management Program (SWMP). COBI also publishes an Annual Report as part of the permit requirements. The current and previous Annual Reports for the previous four years are maintained in the Water Resources Library per permit requirements to maintain records for 5 years (Phase II Permit S9.B.).

Current Documents

Summary of COBI's Phase II Permit Requirements

COBI is a permittee under the Phase II Permit issued by the Department of Ecology (DOE). The Phase II Permit regulates discharges to waters of the state from small municipal separate storm sewer drainage systems (MS4s).

View the DOE Phase II Permit (PDF).

Program Elements Include the following sections of the Phase II Permit.

  1. Public Education and Outreach (S5.C.1)
  2. Public Involvement and Participation (S5.C.2)
  3. Illicit Discharge Detection and Elimination - See Water Resources Libraries for COBI IDDE Manual (S5.C.3)
  4. Controlling Runoff from New Development, Redevelopment and Construction Sites (S5.C.4)

City residents and businesses play a crucial role in protecting water quality in Puget Sound. COBI's SWMP works to eliminate or reduce to the maximum extent practical the impacts to stormwater and surface water. Below are some helpful links and guidance to show you what you can do to help protect water quality.

Helpful Stormwater Resources for COBI Citizens and Businesses

Stormwater Permits and Other Important Information COBI LID Page:

When it Rains it Drains

To request a document copy, see link below for public records requests:

* Western Washington Phase II Municipal Stormwater Permit S5.C.2.b pg. 19 - Each permittee shall post on their website their SWMP and the annual report required under S9.A no later than May 31st of each year.