Source Control – Business Inspection and Stormwater Pollution Prevention Program

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The City of Sammamish is launching a Business Inspection and Stormwater Pollution Prevention program to help prevent stormwater pollution from businesses and government properties. This program implements federal and state requirements, but more importantly, it helps keep our streams, lakes, and groundwater healthy for residents, businesses, and wildlife.

What is Source Control Stormwater Pollution Prevention?

Spills or improperly stored  materials outdoors can get washed into lakes and streams when it rains. This creates polluted stormwater runoff that can harm the water, the ground, and wildlife habitat. Pollution Source Control is accomplished by business practices that keep pollution out of contact with rainwater and prevent unauthorized stormwater discharges. In the simplest of terms, source control is controlling pollution to stormwater at the source. Examples of source control are covering dumpsters, proper use and storage of hazardous materials, and training of staff, which are referred to as Best Management Practices, or BMPs. Examples of some specific common pollutants and BMPs include the following:

Free Technical Assistance

The City will provide free technical assistance to businesses that have the potential to cause stormwater pollution, even in small amounts. The technical assistance will be provided through inspections at qualifying businesses and advice on the use of BMPs for pollution prevention. 


What Types of Businesses Qualify?

The City’s National Pollutant Discharge Elimination System, or NPDES, Permit provides guidance for what types of businesses should be included in a source control program. These include a wide variety of business types and commercial entities that:

If you received a letter or post card in the mail about the City’s Business Inspection and Stormwater Pollution Prevention program, it means your business likely qualifies. This is the case even if you have other environmental permits. Business types that qualify for the program include, among others:

  • automobile and equipment repair and rental, auto body
  • gasoline stations, car washes, auto detail
  • restaurants, cafes, bars, bakeries, food trucks
  • veterinarians and pet shops
  • dentists and medical laboratories
  • institutions, schools, and municipal sites
  • mobile businesses that provide on-site services
  • landscapers, storage yards, and sites with outdoor operations

The full list of qualifying business types by industrial classification code can be found in Appendix 8 of the NPDES Permit.

Register Your Business

Please register your home or business with the City Stormwater Utility at In the registration form, please select Source Control if you received a letter or postcard regarding the Source Control Program.


Why We Have this Program

The Washington State Department of Ecology, through the City’s NPDES Permit, requires Sammamish and other jurisdictions to have a Source Control Program beginning in 2023. Municipalities over a certain size throughout the state are required to have source control programs by the Department of Ecology.


  • August 2022: develop inventory of qualifying businesses
  • May 2022: update municipal code
  • November 2022: announce Source Control – Business Inspection and Stormwater Pollution Prevention Program to potentially qualifying businesses via postcard and webpage
  • December 2022: send upcoming inspection notification to qualifying businesses
  • January 2023: begin business inspections and provide technical assistance
  • Ongoing: annual or semi-annual inspection and technical assistance at qualifying businesses



What action is needed from businesses?

  • If you received a postcard from the City, register your business contact information on this webpage at the link above.
  • Audit your practices and ensure you are using BMPs that help prevent stormwater pollution.
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