Drainage Manual - Past Edition

Snohomish County Drainage Manual
effective from 9/21/1998 to 7/1/2006

Snohomish County Drainage Manual
effective from 7/1/2006 to 8/18/2008

Snohomish County Drainage Manual
effective from 8/18/2008 to 10/19/2009

Snohomish County Drainage Manual
effective from 10/19/2009 to 9/30/2010

Snohomish County Drainage Manual
effective from 10/1/2010 to 1/22/2016

  • Volume I - Minimum Technical Requirements
  • Volume II - Construction Stormwater Pollution prevention best management practices (BMPs)
  • Volume III - Hydrologic Analysis and Flow Control BMPs
  • Volume IV - Source Control BMPs
  • Volume V - Runoff Control BMPs