Chelan County, WA Environmental Rules: Flood Elevation Requirements (2026)
Key Facts
- Residential freeboard
- 3 feet above base flood elevation, minimum
- Nonresidential freeboard
- 1 foot above base flood elevation, minimum
- Administering office
- Chelan County Dept. of Community Development
- BFE source
- FEMA Flood Insurance Study, rev. 9/30/2004
- AO zones
- 3 ft (residential) / 1 ft (nonresidential) above grade
Summary
New construction and substantial improvements in Chelan County's special flood hazard areas must raise the lowest floor, including any basement, at least three feet above the base flood elevation for residential structures, and at least one foot above it for commercial, industrial and other nonresidential structures, under Section 3.20.260.
In all areas of special flood hazard where base flood elevation data has been provided as set forth in Section 3.20.090, Flood hazard areas established, or Section 3.20.100, Use of other base flood data, the following provisions are required: ... Residential Construction. (A) New construction or substantial improvement of any residential structure shall require the lowest floor including basement to be elevated to three feet or higher above the base flood elevation. ... Nonresidential Construction. (A) New construction or the substantial improvement of any commercial, industrial or other nonresidential structure shall require the lowest floor, including basement, to be elevated to or above one foot higher than the base flood elevation.
Full Breakdown
This freeboard exceeds FEMA's minimum 'at or above' base flood elevation (BFE) standard, giving Chelan County an added safety margin. 100 has the floodplain administrator, housed in the Department of Community Development, pull the best available federal, state, or other BFE data instead. 260(2)(B) requires one foot for nonresidential structures, with the AO depth number controlling if higher. 260(2)(D)). Enclosed areas below the lowest floor used only for parking, access or storage need flood vents meeting minimum opening ratios so floodwaters can pass through automatically. The floodplain administrator requires an elevation certificate documenting the as-built lowest-floor elevation for qualifying structures.
Violations & Fines
Building or substantially improving a structure in a special flood hazard area below the required freeboard, without approval from the floodplain administrator in Community Development, violates Chapter 3.20 and can block issuance of the certificate of occupancy or elevation certificate FEMA requires; it can also raise flood-insurance premiums and jeopardize the county's National Flood Insurance Program standing under Section 3.20.050.
Frequently Asked Questions
How high above flood level must a new house be built in Chelan County?
Do commercial buildings have the same flood elevation rule as houses?
Who determines the base flood elevation for my Chelan County property?
Sources & Official References
Other rules in Chelan County
Compare Chelan County to another location·View the Washington environmental rules overview
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