Drainage Manual

Current Manual (January 2016, November 2017 for Volume I)

The documents listed below compose the entire Snohomish County Drainage Manual. The drainage manual is used in concert with Snohomish County code and Snohomish County engineering design and development standards (EDDS).

Proposed Changes

The Snohomish County Department of Conservation and Natural Resources (DCNR) is currently taking written comments on proposed changes to the Snohomish County Drainage Manual, in compliance with its National Pollutant Discharge Elimination System (NPDES) municipal stormwater permit. For more information about the rulemaking process, a summary of the drainage manual updates, and to view the public notice, visit the webpage.