How to Prevent Flooding

Man raking leaves to prevent flooding.

Bellevue’s drainage system—composed of streams, lakes, wetlands, flood detention sites, pipes and ditches—has been designed to hold and carry water during storms to prevent flooding. However, when intense storms hit and overwhelm the system, flooding can occur. Flooding can cause property damage and streambank erosion and also destroy salmon eggs.

To prepare for heavy rains and prevent flooding in your neighborhood:

  • Check storm drains near your home and business and clear away leaves and debris. Clogged grates are often the reason a street floods during a storm.
  • Inspect and clean sediment, debris and rocks from driveways on your property, private roadway culverts, and swales. Culverts (pipes that carry stormwater under a roadway) can get clogged and cause flooding. Property owners are responsible for maintenance of these private drainage systems. If you to hire a service, see list of vendors.
  • Clear debris and leaves from roof gutters and downspouts to protect your property.
  • Do not dump trash, grass clippings, wood, Christmas trees, large rocks or other debris into streams or drainage ditches, which can block the flow of water. If you see dumping, call Utilities at 425-452-7840.
  • Leave natural vegetation on steep slopes and along streams and lakes. Plants slow stormwater runoff, filter pollutants, and stabilize the earth so it won’t wash away.
  • Test your sump pump to make sure it will be in good working order if a storm hits.
  • During a storm, it's normal for streams to rise. Some parking lots and parks are designed to fill with water.
  • Do not attempt to drive through standing water or walk through flooded areas. It's easy to lose your balance.
  • If your home or business is in danger of flooding, call Utilities at 425-452-7840 (24-hour emergency number).
  • For general drainage questions about your property, call Utilities at 425-452-7840 or send an email to Utilities Operations and Maintenance.
  • To find out if your house or business is in a floodplain, see King County's flood insurance rate maps.
  • If your home is in a floodplain, you need flood insurance. Even if you don't live in a floodplain, flood insurance is a good idea because a typical homeowner's insurance policy will not cover water damage unless the damage is caused by interior flooding, such as an overflowing toilet or leaking sink.
  • To see if an elevation certificate is on file for your property in Bellevue, see Elevation Certificates.
  • For information on development projects near streams, wetlands or in floodplain areas, call the city's Permit Center at 425-452-6864.
  • For more information on floods, check Floodsmart. See also What's a 100-year flood?
  • If your home floods, there are certain actions to take.

The city's drainage system, including pipelines and in-stream regional flood control facilities, is detailed in the draft 2015 Storm and Surface Water System Plan.

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