Updating Stormwater Regulations - Project Documents

Project Documents

• Current Stormwater Code and Stormwater Manual

Draft Documents for Public Review - April 1 through May 16 2020

• Summary of Changes
  • Summary of Changes to the Stormwater Code
  • Summary of Changes to the Stormwater Manual
• Draft Stormwater Code 
  • Seattle Municipal Code (Chapters 22.800 - 22.808)
• Draft Stormwater Manual (Joint SPU/SDCI Director's Rule)
  
  • Volume 1 - Project Minimum Requirements
  • Volume 2 - Construction Stormwater Control
  • Volume 3 - Project Stormwater Control
  • Volume 4 - Source Control
  • Volume 5 - Enforcement (no change at this time)
  • Appendix A - Definitions (no change at this time)
  • Appendix B - Chemical Treatment (to be retired)
  • Appendix C - On-site Stormwater Management BMP Infeasibility Criteria
  • Appendix D - Subsurface Characterization and Infiltration Testing for Infiltration BMPs
  • Appendix E - Additional Design Requirements and Plant Lists
  • Appendix F - Hydrologic Analysis and Design
  • Appendix G - Stormwater Control Operations and Maintenance Requirements
  • Appendix H - Financial Infeasibility Documentation for Vegetated Roofs and Rainwater Harvesting
  • Appendix I - Integrated Pest Management Plan

• Draft Stormwater Manual Figures
  • Manual Figure Redlines
• Comment template - Use this to send comments to SPUStormwaterCodeRev@seattle.gov, or via mail. See the get involved page for more information.

The actual Stormwater Code and Manual changes are still to be determined. However, our regulations must be equivalent to Ecology's NPDES 2019 Stormwater Permit (Ecology Permit). We will consider the following topics for our updates:

• Construction site stormwater runoff control/concrete handling
• Technical changes to structural stormwater controls
• Source control
• Clarification of drainage review for Master Use Permit (MUP) and common plans of development
• Combined sewer flow control standard/threshold updates
• Wetland flow control standard
• Stormwater/combined mainline extension requirement clarification
• Addition and clarification of definitions
• On-site Stormwater Management (OSM) list approach-