Flood Protection

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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.

Flooding preparation

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:

Prepare for heavy rains and prevent flooding in your neighborhood
Keep yourself and your property safe during heavy rains
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.)

Actions to Take During Heavy Rain and Flooding

There are a number of things you can do to prepare for and respond to heavy rains, so you can prevent flooding in your home.

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. City employees clear storm drains, but it's hard to get to all 20,000 public drains. We appreciate your help.
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.
Install a sump pump. If you already own a sump pump, test it to make sure it will be in good working order if a storm hits.
Do not dump trash, grass clippings, wood, Christmas trees, large rocks or other debris into streams or drainage ditches. These activities 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.
Know how to shut off your electricity, gas and water at main switches and valves. You may need to shut off these utilities if your home floods.
- Puget Sound Energy has an online how-to for electric shutoff and gas shutoff, or call 1-888-225-5773 for guidance.
- Learn how to locate your water meter and shut off valve, or call Bellevue Utilities at 425-452-7840 for help.
Have an emergency kit prepared ahead of time in case you need to evacuate your home.

How to stay safe during heavy rains:

Call 911 for life-threatening emergencies.
Call Bellevue Utilities at 425-452-7840 (24-hour emergency number) if your home or office is in danger of flooding.
During a storm, it's normal for streams to rise. Some parking lots and parks are designed to fill with water.
Unplug all electrical appliances and turn off gas at the meter. Move valuables to higher floors.
Do not attempt to walk through flooded areas. It's easy to lose your balance.
Do not attempt to drive through standing water. Even a small amount of water can stall your car. If your car stalls in rapidly rising waters, abandon it immediately and climb to higher ground.
Stay away from fallen power lines and electrical wires. Assume any downed power line is an energized power line.
Learn more how to prepare for a flood in King County.

What to do if your property floods:

When reentering your home, use a flashlight. Do not use candles or cell phone lights in case of a gas leak.
Turn off power at the circuit breaker for areas that have flooded. If the circuit breaker is wet, contact Puget Sound Energy at 1-888-225-5773.
Check for structural damage and beware of gas leaks, electric shorts and live wires.
King County has information on how to clean up after a flood.
Call your insurance agent for information on flood claims.

Related Information

For general drainage questions about your property, call Utilities at 425-452-7840 or send an email to Utilities Operations and Maintenance.
If you are considering development near water sources, please consult Environmental and Critical Areas.
Learn more about Bellevue’s Streams, Lakes and Wetlands, their natural functions, and the regulations that protect them.
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). Real-time data allow users to know current water levels and track the rate of rise or fall of the water level. The rate of rise can be helpful for property owners to decide when to implement flood protection measures (i.e., sandbags). In addition, property owners can monitor the water level near their property when they're away. 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.