Stormwater Code and Manual Update 2026 - Project Documents
Project Documents
The following documents outline the summary of changes we made to the code and manual.
- Summary of Changes to Stormwater Code & Manual (July 2025)
Draft documents for the 2026 City of Seattle Stormwater Code
- Draft Stormwater Code Ordinance (July 2025)
- Draft Stormwater Manual (July 2025)
- Volume 1 – Project Minimum Requirements
- Volume 2 – Construction Stormwater Control
- Volume 3 – Project Stormwater Control
- Volume 4 – Source Control
- Volume 5 – Enforcement
- Appendix A – Definitions
- Appendix B – Additional Submittal Requirements
- Appendix C – Onsite Stormwater Management BMP Infeasibility Criteria
- Appendix D – Subsurface Investigation and Infiltration Testing for Infiltration BMPs
- Appendix E – Additional Stormwater Design Requirements
- Appendix F – Hydrologic Analysis and Design
- Appendix G – Stormwater Control Operations and Maintenance Requirements
- Appendix H – Financial Feasibility Documentation for Vegetated Roofs and Rainwater Harvesting
- Appendix I - Landscape Management Plans and Integrated Pest Management
- Appendix J – Contaminated Sites
- Appendix K – Plant and Tree list