Stormwater Permits

City Stormwater Regulations

The following is a list of regulations/design manuals adopted by the City of Mercer Island:

• Standards for new development and redevelopment MICC 15.09.050
• Washington State Department of Ecology Stormwater Management Manual for Western Washington (2019)
• Low Impact Development Technical Guidance Manual for Puget Sound (2012)

Guidance / Handouts / Worksheets

The following is a list of informational handouts, guidance and worksheets regarding stormwater:

• Tip Sheet for small projects (creating <5,000 square feet of new plus replaced hard surfaces)
• Stormwater Permit Submittal Worksheet for small projects
• LID Infeasibility Map
• Storm Water Drainage Review and Permit Process for Single Family Residences
• Engineering Plan Submittal Requirements
• Permeable Paver Block Design Guidelines for Single Family Residential Projects
• List of Clearing and Grading Best Management Practices
• Covenant for new private drainage facilities
• Detention system sizing chart for projects with less than 9,500 square feet of impervious surface
• Fee in Lieu of Stormwater Detention Table (July 2024)