Flood Protection

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.

Are you prepared for flooding?

• To determine whether your property is located in a floodplain, see the flood insurance rate maps for the City of Bellevue.
• To determine whether your property is located in the Special Flood Hazard Area, see our list of Elevation Certificates on file.
• To learn about drainage problem warning signs, visit Drainage Around Your Home.

• See Actions to Take with Rain and Flooding to:

1. Prepare for heavy rains and prevent flooding in your neighborhood
2. Keep yourself and your property safe during heavy rains
3. Know what to do if your property floods

• Become familiar with how the City of Bellevue’s Office of Emergency Management supports efforts to prevent, mitigate, respond and recover from hazardous events.

Flood insurance

• 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.
• Flood insurance can be purchased through the National Flood Insurance Program (NFIP), which provides flood insurance for all properties. Visit NFIP Floodsmart for more information on floods and flood insurance.
• Bellevue residents receive a 25% discount on NFIP policies due to Bellevue’s floodplain management program. (There is a 30-day waiting period before the policy goes into effect.)

For more information:

• For general drainage questions about your property, call Utilities at 425-452-7840 or send an email to Utilities Operations and Maintenance.
• Learn more about Bellevue’s Streams, Lakes, and Wetlands, their natural functions, and the regulations that protect them.
• For information on development projects near streams, wetlands or in floodplain areas, see the Land Use Code or call the city's Permit Center at 425-452-6864.
• The city's drainage system, including pipelines and in-stream regional flood control facilities, is detailed in the current Storm and Surface Water System Plan.
• Real-time water levels for Lake Sammamish and Mercer Creek (Slough). The Mercer Slough link also provides real-time flow data.
• For more information about floodplains in the region, see King County’s Be Flood Ready guide and King County Flood Insurance Rate Maps.