Bellevue, WA Environmental Rules: Flood Elevation Requirements (2026)
Key Facts
- Freeboard
- 1 foot above base flood elevation
- FIS reference
- King County FIS, Aug 19, 2020
- Governing code
- BCC 23.12.322.1.4 (IRC R322.1.4)
- NFIP status
- Regular Program, no mapped SFHA
- Adopted
- Ordinance 6781 § 7, 2024
- Enforcement
- Building official, BCC 23.05.170
Summary
Bellevue requires new residential construction in flood hazard areas to sit at least one foot above the base flood elevation shown on FEMA's King County Flood Insurance Study, a freeboard margin built into the city's amended International Residential Code. The rule applies wherever a FEMA flood hazard map or the King County FIS controls the site.
R322.1.4 Establishing the design flood elevation. The design flood elevation shall be used to define flood hazard areas. At a minimum, the design flood elevation shall be one foot above the higher of the following: 1. The base flood elevation at the depth of peak elevation of flooding, including wave height, that has a 1 percent (100-year flood) or greater chance of being equaled or exceeded in any given year, or 2. The elevation of the design flood associated with the area designated on a flood hazard map as identified by the Federal Emergency Management Agency in an engineering report entitled "The Flood Insurance Study (FIS) for King County, Washington, and Incorporated Areas," dated August 19, 2020, and any revisions thereto, with the accompanying Flood Insurance Rate Maps (FIRMs), dated August 19, 2020, and any revisions thereto.
Official source re-checked September 8, 2026: no newer edition of the code had been published (publisher’s edition: current through Ordinance 6929, passed July 14, 2026).
Full Breakdown
4 as part of Bellevue's 2021 International Residential Code adoption under Ordinance 6781, Section 7 (2024). It sets the design flood elevation, the number used to define flood hazard areas, at a minimum of one foot above the higher of two benchmarks: the base flood elevation at peak flood depth including wave height for a flood with a 1 percent annual chance of being equaled or exceeded (the 100-year flood), or the elevation shown on FEMA's engineering report, the Flood Insurance Study for King County, Washington, dated August 19, 2020, with its accompanying Flood Insurance Rate Maps of the same date.
5, Floodplain/Floodway Analysis, with studies submitted in enough detail for full review. 2 separately requires a floodway analysis in riverine areas where floodways have not been designated. A footnote to the adopted IRC climatic table confirms Bellevue is a Regular Program NFIP community with no mapped Special Flood Hazard Area, participating since March 12, 1974.
Violations & Fines
A residence built below the required design flood elevation is a technical-code violation enforced under BCC 23.05.170: the city can pursue it as a civil violation under Chapter 1.18 BCC with a monetary penalty, or as a misdemeanor punishable under the Bellevue Criminal Code, Title 10 BCC. The building official can also withhold approval until the required lowest-floor elevation certification is submitted and accepted.
Frequently Asked Questions
How high above flood level must a new Bellevue home be built?
What if my lot doesn't have a listed design flood elevation?
Does Bellevue participate in the National Flood Insurance Program?
Sources & Official References
Other rules in Bellevue
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Flood Elevation Requirements in Nearby Cities
How other cities in King County handle flood elevation requirements.