Drainage Manual - Past Edition
Snohomish County Drainage Manual Effective from September 21, 1998 to July 1, 2006
- 1992 Department of Ecology Stormwater Manual - Volume I (PDF)
- 1992 Department of Ecology Stormwater Manual - Volume II (PDF)
- 1992 Department of Ecology Stormwater Manual - Volume III (PDF)
- 1992 Department of Ecology Stormwater Manual - Volume IV (PDF)
- September 21, 1998 Snohomish County addendum (PDF) to 1992 Ecology Stormwater Manual
Snohomish County Drainage Manual Effective from July 1, 2006 to August 18, 2008
- 1992 Department of Ecology Stormwater Manual - Volume I (PDF)
- 2005 Department of Ecology Stormwater Manual - Volume II (PDF)
- 1992 Department of Ecology Stormwater Manual - Volume III (PDF)
- 1992 Department of Ecology Stormwater Manual - Volume IV (PDF)
- September 21, 1998 Snohomish County addendum (PDF) to 1992 Ecology Stormwater Manual
Snohomish County Drainage Manual Effective from August 18, 2008 to October 19, 2009
- 1992 Department of Ecology Stormwater Manual - Volume I (PDF)
- 2005 Department of Ecology Stormwater Manual - Volume II (PDF)
- 1992 Department of Ecology Stormwater Manual - Volume III (PDF)
- 2008 Snohomish County Drainage Volume IV (PDF)
- September 21, 1998 Snohomish County addendum (PDF) to 1992 Ecology Stormwater Manual
Snohomish County Drainage Manual Effective from October 19, 2009 to September 30, 2010
- 1992 Department of Ecology Stormwater Manual - Volume I (PDF)
- 2005 Department of Ecology Stormwater Manual - Volume II (PDF)
- 1992 Department of Ecology Stormwater Manual - Volume III (PDF)
- October 5, 2009 Snohomish County Addendum to Volume III (PDF)
- 2008 Snohomish County Drainage Volume IV (PDF)
- September 21, 1998 Snohomish County addendum (PDF) to 1992 Ecology Stormwater Manual
Snohomish County Drainage Manual Effective from October 1, 2010 to January 22, 2016
- Volume I (PDF) - Minimum Technical Requirements
- Volume II (PDF) - Construction Stormwater Pollution prevention best management practices (BMPs)
- Volume III (PDF) - Hydrologic Analysis and Flow Control BMPs
- Volume IV (PDF) - Source Control BMPs
- Volume V (PDF) - Runoff Control BMPs
Snohomish County Drainage Manual Effective January 23, 2016 to June 30, 2021
- Volume I (PDF) - Minimum Technical Requirements
- Volume II (PDF) - Construction Stormwater Pollution prevention best management practices (BMPs)
- Volume III (PDF) - Hydrologic Analysis and Flow Control BMPs
- Volume IV (PDF) - Source Control BMPs
- Volume V (PDF) - Runoff Control BMPs
Current Drainage Manual
View the current edition of the Drainage Manual.
The county is updating its stormwater management regulations to comply with federal and state law. View more details and draft updates to the county's Drainage Manual.