Surface Water Management

Snohomish County's Surface Water Management (SWM) Division provides a variety of programs and services for reducing road and property flooding and preserving and improving the health of Snohomish County's water resources and natural systems. We focus on four areas of service:

  • Clean water in rivers, streams and lakes;
  • Habitat for fish and aquatic wildlife;
  • River flooding and erosion;
  • Stormwater drainage systems.

We work in partnership with the residents of Snohomish County. You can find us responding to water-quality problems and complaints, monitoring river levels during flood season, maintaining drainage systems, managing habitat improvement projects and more.

SWM's Mission, Values, and Priorities
Summary List of SWM Services

SWM Highlights

  1. Port Susan

    The Port Susan Marine Stewardship Area is a haven for wildlife and a mecca for people to escape back into nature located on the Salish Sea in Snohomish County of Washington State.

Draft 2017 Stormwater Management Program Plan Available for Review


The draft 2017 National Pollutant Discharge Elimination System (NPDES) Stormwater Management Program Plan is available for review. This draft plan describes programs the county will implement in 2017 to comply with the NPDES municipal stormwater permit, which is a part of the federal Clean Water Act. Find out more about the NPDES permit, what the county does to meet its requirements, and how you can comment on these programs by visiting our NPDES page.

Lake Serene Project


Learn latest details about the Lake Serene Project.