Glenn County, CA Environmental Rules: Flood Elevation Requirements (2026)
Key Facts
- Governing section
- Glenn County Code § 15.54.100(D)
- Elevation certified by
- Registered engineer or surveyor
- Verified by
- County building inspector
- AO zone rule
- FIRM depth number plus 1 ft, or 3 ft minimum
- Certification points
- Plan check, pre-construction, final inspection
Summary
In unincorporated Glenn County, new and substantially improved structures built in a special flood hazard area must have their lowest floor elevation certified by a licensed engineer or surveyor and verified by the county building inspector. Glenn County Code Section 15.54.100(D) sets the elevation and floodproofing rules, including a stricter add-on standard for the AO flood zone.
The elevation of the lowest floor, including basement, shall be certified by a registered professional engineer or surveyor, and verified by the community building inspector to be properly elevated. Such certification and verification shall be provided to the flood plain administrator at plan check, prior to vertical construction, and at final inspection. ... New and substantially improves residential structures located within AO Zones and requires to have their lowest floor elevated above the highest adjacent grade (HAG) at least as high as the flood depth number specified on the community Flood Insurance Rate Map (FIRM). California Residential Code (CRC) Section 322.2.1(2) also requires lowest floors to be elevated to a height about the highest adjacent grade of not less than the depth number on the FIRM plus 1 foot or not less than 3 feet if the depth number is not specified. The stricter standard shall apply.
Full Breakdown
100(D)(2) requires that the elevation of the lowest floor, including any basement, be certified by a registered professional engineer or surveyor and verified by the community building inspector to be properly elevated, with that certification delivered to the flood plain administrator at plan check, before vertical construction starts, and again at final inspection. 100(D)(3) so the structure stays watertight below the flood elevation, provided a registered civil engineer certifies the design. 100(D)(6) sets an even more specific elevation rule: new and substantially improved residential structures must have their lowest floor elevated above the highest adjacent grade at least as high as the flood depth number shown on the county's Flood Insurance Rate Map.
1(2) independently requires the lowest floor to sit above the highest adjacent grade by the FIRM depth number plus one foot, or by at least three feet if no depth number is listed, and the code directs that the stricter standard shall apply. 100(D)(7), tied to the California Building Code's incorporation of ASCE 7 and ASCE 24 design standards. 090.
Violations & Fines
Failing to provide the elevation or floodproofing certification required by Section 15.54.100(D) puts a project out of compliance with Chapter 15.54, which Section 15.54.060 makes a misdemeanor, in addition to any other lawful enforcement action the county chooses to pursue. Because the elevation certificate is due at plan check, before vertical construction, and again at final inspection, the building official can stop a non-compliant foundation before it is built on.
Frequently Asked Questions
Who certifies a building's flood elevation in Glenn County?
Does Glenn County require extra elevation above the FEMA flood height?
Can a nonresidential building be floodproofed instead of elevated?
Sources & Official References
Other rules in Glenn County
California rules heatmap·Compare Glenn County to another location·View the California environmental rules overview
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