Proactive maintenance of the City's drainage infrastructure helps to prevent urban flooding and reduces the amount of pollution flowing into our lakes, streams and the Puget Sound.  SWM maintains over 12,000 catch basins and manholes, over 150 miles of pipe and 30 miles of open channel and ditch, 204 residential retention / detention (R/D) ponds and six regional detention facilities. SWM is dedicated to providing services in an effective and efficient manner and is prepared to respond to flooding, spills and other emergencies that may arise 24 hours a day.

Maintenance activities are grouped into the following categories:

• Construction program- includes major maintenance projects to eliminate chronic flooding areas, the repair of catch basins and manholes contained within the city's asphalt overlay program and general construction activities such as ditch cleaning or repairing broken pipe.
• Pond program- focuses primarily on mowing and vegetation control at the city's residential and regional detention facilities. The program also includes selective re-grading, exterior landscaping improvements, noxious weed control and water quality improvements.
• Contracted services program- is comprised of service contracts related to catch basin / manhole cleaning and street sweeping. 
• Emergency response/severe weather program- focuses on the operation and maintenance of our existing stormwater system during severe weather events. SWM crews are also an important part of the City's snow and ice team.