Updating Stormwater Regulations - Project Documents

Project Documents

• Current 2016 Stormwater Code and Stormwater Manual

Draft Documents for Public Review #3 - January 11 through February 19, 2021

• Summary of Changes
  • Summary of Changes to the Stormwater Code
  • Summary of Changes to the Stormwater Manual
• Draft 2021 Stormwater Code
  • Seattle Municipal Code (Chapters 22.800 - 22.808)
• Related Code and Director's Rules
  • New Draft SPU Public Drainage System Director's Rule (includes Storm Mainline Extension rules and the Public Drainage System design requirements that are currently in SPU CAM 1180)
  • New Draft Grading Code Revisions (SMC Subtitle IB Chapter 22.170)
  • New Draft Land Use Code Revisions
• Draft 2021 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- Additional Submittal Requirements
  • 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

If you wish to submit a comment, please complete the comment template and email it to SPUStormwaterCodeRev@seattle.gov or mail your comments to:

Sherell Ehlers
Seattle Public Utilities
700 Fifth Ave, Suite 4400
PO Box 34018
Seattle, WA 98124-4018

Email correspondence is preferred.

Note: 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).

SEPA Determination of Non-Significance December 10-24, 2020

We have conducted a State Environmental Protection Act (SEPA) environmental review of the City of Seattle's proposed 2021 Stormwater Code and Rule Update. The lead agency, Seattle Public Utilities (SPU), has issued a Determination of Non-Significance (DNS). This proposal involves the adoption of ordinances amending the City of Seattle's Stormwater Code and associated Directors' Rule. 

• SEPA Environmental Checklist for the City of Seattle 2021 Stormwater Code and Rule Update
• Determination of Non-Significance (DNS)

You can see all of the documents related to the SEPA review and DNS listed under the headings below.

Draft Documents for Public Review #2 - November 2 - November 20, 2020

• Summary of Changes
  • Summary of Changes to the Stormwater Code
  • Summary of Changes to the Stormwater Manual (Volume 1 and Appendices B and I only)
• 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
  • Appendix B - Additional Submittal Requirements
  • Appendix I - Landscape Management Plan and Integrated Pest Management

Draft Documents for Public Review #1 - April 1 through May 16 20, 2020

These documents were posted for the review period of 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