Urban Drainage

Report a Problem

Each year surface water management staff responds to more than 325 drainage complaints called in by citizens. Report a drainage problem in your neighborhood or request a drainage investigation. If you have trouble using the drainage investigation request form, please contact our Drainage Services Coordinator via email or call 425-388-3464.


In order for the publicly and privately owned storm drainage facilities (e.g., detention ponds, biofiltration swales, detention vaults, etc.) to function properly, each needs regular maintenance. This program helps ensure that both public and private drainage facilities are regularly maintained by their owners. The ultimate goal of the program is to help reduce flooding of private property and public roads, improve water quality, and protect aquatic habitat.

In 2009, the program was expanded to comply with recent changes to the county’s National Pollutant Discharge Elimination System (NPDES) permit, which is mandated by the federal Clean Water Act. To comply with these regulatory changes, the county must inspect public and private storm drainage facilities, determine whether the facilities meet performance standards, and require facility owners to correct any problems or deficiencies.

For more information call 425-388-3464.


Snohomish County Department of Public Works (DPW) has adopted a revised Drainage Manual governing construction. The county's Drainage Manual, adopted by rule in accordance with Chapter 30.82 SCC, should be reviewed before any beginning any project possibly affecting drainage. The current version of the Drainage Manual applies to any development or redevelopment projects vested after September 30, 2010. The current Drainage Manual also applies to pollution-generating activities at sites with existing development.

Please address any questions to Bill Leif by calling 425-388-3148.


Under SCC 7.54, owners of storm drainage facilities are legally responsible for maintaining the facilities to ensure they continued to function properly. The Snohomish County Drainage Manual contains all applicable maintenance requirements. In many cases, maintenance will consist of removing sediment, tree roots, or trash from the facilities. In other cases, more extensive maintenance or repair work will be needed. Typically, the maintenance or repair of a storm drainage facility requires special equipment and skills, and should be carried out by a licensed contractor. List of storm drainage facility cleaning contractors (PDF).


Surface water management also offers an extensive look at drainage data currently found throughout Snohomish County, including some cities. Residents, developers, and others can use the information to find comprehensive information relating to drainage systems near their home, a future development or an area of interest.

For more information, contact Surface Water Management, 425-388-3464.