Stormwater Codes and Rules Update - Documents

2021 Stormwater Code and Manual Updates

Summary of Changes

• Summary of Changes to the Stormwater Code
• Summary of Changes to the Stormwater Manual

Stormwater Code (Seattle Municipal Code)

• 2021 Stormwater Code (Clean Version of full SW Code)
• 2021 Stormwater Code Ordinance, Council Bill 120044

2021 Stormwater Manual (Joint Director's Rule SPU DWW-200/SDCI 10-2021)

• Full Seattle Stormwater manual (Tracked-changed version with changes from the 2016 code in blue text with underlines)

New SPU Public Drainage System Requirements Director's Rule (DWW-210)

The following are archives of previous versions of the Seattle Stormmwater Code and Manual and supporting documents. For the current Seattle Stormwater Code and Manual and supporting documents, see Stormwater Code.

2016 Stormwater Code and Manual

2016 Stormwater Code

• 2016 Stormwater Code
• 2016 Stormwater Code Ordinance Council Bill (CB 118465)

2016 Stormwater Manual

• Stormwater Manual - Volumes 1-5 and Appendices (Directors' Rules SDCI 21-2015/SPU DWW 200) 
• Clarification Sheet for the 2016 Stormwater Manual
• Clarification Attachment 1: On-Site Performance Standard BMP Design (Additional to Appendix F - Hydrologic Analysis and Design)
• Clarification Attachment 2: BMP 10 Fueling at Dedicated Stations (Clarifications for Volume 4, Section 3.2.2)

2016 Forms and Documents

• Small Demolition Construction Stormwater Control Soil Management Plan
• Standard Construction Stormwater Control and Soil Amendment Plan (PDF) | CAD Version | CTB File
• Standard Drainage and Wastewater Control (DWC) Plan (PDF) | CAD Version | CTB File
• On-site Stormwater Management - List Approach Calculator
• Simple Infiltration Checklist - coming soon
• Pilot Infiltration Test (PIT) Checklist - coming soon
• Pre-Sized Flow Control Calculator - For projects with required flow control of less than 10,000 square feet of hard surface 
• Memorandum of Drainage Control
• Side Sewer Easement Agreement
• Side Sewer Joint Use and Maintenance Agreement
• Certification/Attestation of Mailing Notification Form

2009 Stormwater Code and Manual

2009 Stormwater Code

• 2009 Stormwater Code Ordinance
• 2015 Revision to 2009 Stormwater Code Ordinance

2009 Stormwater Manual

• Director's Rule 15-2009 / SPU 2009-003, Vol. I - Source Control Technical Requirements Manual
• Director's Rule 16-2009 / SPU 2009-004, Vol. II - Construction Stormwater Control Technical Requirements Manual
• Director's Rule 17-2009 / SPU 2009-005, III - Stormwater Flow Control and Water Quality Treatment Technical Requirements Manual
• Director's Rule 18-2009 / SPU 2009-006, Vol. IV - Stormwater Code Enforcement Manual

2009 Forms and Documents

• Standard Construction Stormwater Control and Soil Amendment Standard Plan
• Standard Drainage Control Plan - Small Projects
• Green Stormwater Requirement Calculator
• Pre-Sized Flow Control Calculator
• Infiltration Sizing for Small Projects Table
• DWW - 202 Small Project for OnSite Infiltration - No POD Procedure

2009 Reference Materials

• Director's Rule 13-2010 / SPU 5-2010, Groundwater / Dewatering
• Director's Rule 15-2012, Requirements for Green Stormwater Infrastructure to the Maximum Extent Feasible for Single-Family Residential and Parcel-Based Projects
• Director's Rule 16-2012, Requirements for Green Stormwater Infrastructure to the Maximum Extent Feasible for Roadway, Trail, and Sidewalk Projects, DWW-201.2
• Directors Rule: DWW-430.1, Identified Public Combined Sewer Basins Where Flow Control is Not Required (Note: if the immediate downstream drainage system is considered to be "Capacity Constrained," Flow Control may still be required.)
• Tip 531, Post Construction Soil Management
• Approved Tree List - Note: Trees in the "Small Category" are not eligible for credit