Vacaville, CA Environmental Rules: Flood Elevation Requirements (2026)
Key Facts
- Residential floor standard
- at or above base flood elevation
- AO zone standard
- FIRM depth number, or 2 ft if none shown
- Certification required
- by registered engineer or surveyor
- Nonresidential option
- dry-floodproofing in lieu of elevation
- Freeboard above BFE
- none specified beyond base flood elevation
Summary
Vacaville requires new residential construction and substantial improvements in a mapped flood zone to have the lowest floor, including any basement, built at or above the base flood elevation, with AO-zone structures elevated to the FIRM depth number or at least two feet above the highest adjacent grade. A licensed engineer or surveyor must certify the finished elevation to the Floodplain Administrator.
1. Residential construction, new or substantial improvement, shall have the lowest floor, including basement: a. In an AO zone, elevated above the highest adjacent grade to a height equal to or exceeding the depth number specified in feet on the FIRM, or elevated at least two feet above the highest adjacent grade if no depth number is specified. b. In an A zone, elevated to or above the base flood elevation; said base flood elevation shall be determined by one of the methods in Section 14.18.040.040.B. c. In all other zones, elevated to or above the base flood elevation. 2. Upon the completion of the structure, 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.
Full Breakdown
C sets the elevation standard by flood zone. In an AO zone, the lowest floor must clear the highest adjacent grade by the depth number printed on the Flood Insurance Rate Map, or by at least two feet if no depth number is shown. B; the code does not add an extra freeboard cushion above that elevation. 3. 2 requires the finished lowest-floor elevation be certified by a registered professional engineer or surveyor and verified by the City building inspector before the certification goes to the Floodplain Administrator. 040. 4.
Violations & Fines
Building below the required elevation without an approved variance violates Section 14.18.030.030 and is a misdemeanor; it also voids the flood-insurance rate reduction the elevation certificate would otherwise secure and can force costly retrofits before the City will issue a certificate of occupancy. The Floodplain Administrator can withhold final inspection until a licensed engineer or surveyor submits the required as-built elevation certification.
Frequently Asked Questions
How high above the flood level must a Vacaville home be built?
Does Vacaville require extra freeboard above the base flood elevation?
Who verifies the finished elevation meets the standard?
Sources & Official References
Other rules in Vacaville
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Flood Elevation Requirements in Nearby Cities
How other cities in Solano County handle flood elevation requirements.