Project 2


Stormwater is water that runs off impervious surfaces such as roads, parking lots, and rooftops, as well as runoff from bare earth that can deliver excess sediment, nutrients and/or bacteria to surface waters. The County protects water quality by cleaning streets and treating the stormwater runoff containing bacteria, nutrients, heavy metals, and gas/oil through facilities such as bioswales, rain gardens, and created wetlands. The risk of flooding is also reduced by properly cleaning, sizing, and routing pipe and ditch infrastructure to receiving waters. Development and land disturbing activities are required to manage their stormwater as part of the land use permitting process. 


Street Sweeping

San Juan County implemented enhanced vacuum assisted street sweeping beginning in 2019. Street sweeping occurs monthly, May through October, to prevent pollutants from entering our drainage system. Street sweeping allows the safe removal of heavy metals, rubber, hydrocarbons left by our vehicles. Target areas include: Eastsound, Orcas Village, Lopez Village, and the Friday Harbor, Orcas and Lopez Ferry Terminals. Moving cars on your designated street sweeping day is an important way you can help reduce pollution from our waterways and storm drain system. Here is the 2021 schedule:

Orcas - Eastsound, Orcas Village, and the WSF Terminal 

  • 2nd Mondays, May thru October, between the hours of 7:30am and 11am

Lopez - Lopez Village and WSF Terminal

  • 3rd Mondays, May thru October, between the hours of 7:30Street Sweepam and 11am

San Juan Island - Friday Harbor and the WSF Terminal are swept by the Town of Friday Harbor per their designated schedule.

Storm System Cleaning

San Juan County conducts annual catch basin and storm line cleaning before the first heavy rains of the fall, to ensure the system is functioning properly and to prevent accumulated sediment in the system from discharging into waterways. Storm system cleaning and regular street sweeping, together, help protect our waters.

Storm System Cleaning

Stormwater Monitoring

Stormwater sampling provides quantitative data to determine pollutant concentrations in runoff. Stormwater sampling is conducted twice a year before and after the first Stormwater Monitoringflush of fall rains. San Juan County has been sampling stormwater since 2012 on San Juan, Orcas, and Lopez Islands at a  variety of point sources and test for nutrients, bacteria, heavy metals and hydrocarbons.


Stormwater permits can be applied for through the following links for The Department of Community Development and through the Online Permit Center

Environmental Stewardship provides review, approval and technical assistance to the Stormwater permit process.  

Application Requirements:

San Juan County's stormwater management requirements differ depending on the size project and scope of work. San Juan County reference the Minimum Requirements provided in the 2005 Washington State Department of Ecology (DOE) Stormwater Manuals (see under Quick Links on right).

Clearing and Grading Permits: 

All Clearing and Grading Permits require a stand-alone Large Stormwater Management Plan DOE MINIMUM REQUIREMENTS #1-10.

Building Permits:

Stormwater management plans differ depending on the amount of proposed impervious surfaces. All building permits applications require that the Impervious Worksheet and Stormwater Minimum Requirement Certification be submitted as part of the permit package regardless of project size.

The Impervious Surface Worksheet will determine what size Stormwater Management Plan is required for your project. The Stormwater Management Plan Application is required for projects proposing over 2000 square feet of impervious surfaces.

Stormwater Application Forms:

  1. Impervious Surface Worksheet
  2. Stormwater Minimum Requirement Certification
  3. Stormwater Management Plan Application  
  4. Stormwater Management Certification for Utilities


There are several active stormwater projects in various stages of planning, design, and construction throughout the County. These projects construct natural treatment systems to provide stormwater flow control, infiltration, and treatment; they are partially funded by the Department of Ecology. 

San Juan County Clean Water icon

To view the project factsheets and design plans, please click on the links below:

Lopez Island:

Orcas Island:


The Stormwater Basin Planning Volume I & II (2015) provides a general overview of watershed and infrastructure conditions throughout the County and offers recommendations for improvements. This information feeds into the County's management policies and capital improvement programming for Clean Water. 

To view the Stormwater Basin Plans, please click on the links below:

Whale Banner


San Juan County aims to reduce stormwater runoff and improve water quality by supporting stormwater management practices. When water infiltrates into the soil, it is filtered and replenishes our aquifer or flows into our local waterways. As climate changes, more frequent, higher intensity storms and flooding events will occur. These rainfall events overwhelm the capacity of our stormwater infrastructure causing localized flooding, increased erosion, and flushing of contaminants into local waterways. 

San Juan County's Department of Environmental Stewardship is continually evaluating its projects and management strategies to ensure climate risks are addressed, including but not limited to: 

  • Elevated water temperatures and harmful algal blooms
  • Sea level rise and coastal flooding
  • Stream and drainage culvert flood capacity
  • Drought and saltwater intrusion