Thousand Oaks, CA Environmental Rules: Flood Elevation Requirements (2026)
Key Facts
- Governing chapter
- TOMC Chapter 7, Flood Damage Prevention
- Elevation standard
- Lowest floor at or above BFE
- Freeboard above BFE
- None required by local code
- Administrator
- City Engineer as Floodplain Administrator
- Certification
- Registered civil engineer or licensed surveyor
- Violation classification
- Misdemeanor under § 4-7.03(c)
Summary
In FEMA-mapped special flood hazard areas, Thousand Oaks requires the lowest floor of new construction and substantial improvements, including basements, to sit at or above the base flood elevation (BFE). The City Engineer enforces the standard as Floodplain Administrator under TOMC Chapter 7.
(i) Residential construction. All new construction or substantial improvements of residential structures shall have the lowest floor, including basement: (aa) In AE, AH, A1-30 Zones, elevated to or above the base flood elevation. (ab) 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 (2') feet above the highest adjacent grade if no depth number is specified.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: 2026 S-78: 2026 S-78 Supplement contains: Current city legislation passed through March 31, 2026).
Full Breakdown
05(a)(4)(i) sets the elevation floor for residential building in AE, AH and A1-30 zones: the lowest floor, including any basement, must be built to or above the base flood elevation shown on the FEMA Flood Insurance Rate Map. In an AO zone, the structure must clear the highest adjacent grade by the depth number printed on the FIRM, or by two feet if no depth number is listed. 04(b)(3), and once the building is finished a registered civil engineer or licensed land surveyor must certify the lowest floor elevation, verified by the City's building inspector.
05(a)(4)(ii) can either meet the same elevation or be dry floodproofed watertight below that line, with the design certified by a registered civil engineer or architect. 05(a)(3) and (a)(4)(iii) carry their own venting and material rules. 04(b)(1). 05(a)(4)(v)(ab).
Violations & Fines
Constructing or altering a structure in a mapped flood hazard area without meeting § 4-7.05's elevation and floodproofing standards violates TOMC § 4-7.03(c), which makes noncompliance a misdemeanor. The City Council may take any lawful action needed to prevent or remedy a violation, and a structure lacking the required elevation certificate is presumed noncompliant until the owner produces it, per the chapter's violation definition.
Frequently Asked Questions
How high must a new house be built in a Thousand Oaks flood zone?
Does Thousand Oaks require extra freeboard above the base flood elevation?
Who signs off on flood elevation compliance in Thousand Oaks?
Sources & Official References
Other rules in Thousand Oaks
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Flood Elevation Requirements in Nearby Cities
How other cities in Ventura County handle flood elevation requirements.