Whittier, CA Environmental Rules: Flood Elevation Requirements (2026)
Key Facts
- General rule
- Lowest floor at/above base flood elevation
- Zone AH/AO rule
- Above adjacent grade per FIRM depth number, or 2 ft min
- Certification required
- By registered engineer or surveyor
- Flood-vent minimum
- 1 sq in opening area per sq ft enclosed
- Manufactured homes
- Must also meet base flood elevation and anchoring rule
Summary
New construction and substantially improved structures in Whittier's mapped flood hazard areas must have their lowest floor, including any basement, elevated to or above the base flood elevation and certified by a licensed engineer or surveyor before the floodplain administrator will sign off, per WMC §15.40.160(C).
1.New construction and substantial improvement of any structure shall have the lowest floor, including basement, elevated to or above the base floor elevation. Nonresidential structures may meet the standards in subsection (C)(3) of this section. Upon the completion of the structure the elevation of the lowest floor including basement shall be certified by a registered professional engineer or surveyor, or verified by the community building inspector to be properly elevated. Such certification or verification shall be provided to the floodplain administrator.2.New construction and substantial improvement of any structure in Zone AH or AO shall have the lowest floor, including basement, elevated above the highest adjacent grade at least as high as the depth number specified in feet on the FIRM, or at least two feet if no depth number is specified.
Full Breakdown
160(C)(1) sets the baseline rule for all new construction and substantial improvements: the lowest floor, including a basement, must be elevated to or above the base flood elevation, with the completed elevation certified by a registered professional engineer or surveyor, or verified by the community building inspector, and that certification provided to the floodplain administrator. 160(C)(2): the lowest floor must sit above the highest adjacent grade at least as high as the depth number shown on the FIRM, or at least two feet if no depth number is listed, again with engineer or surveyor certification.
160(C)(3), watertight below the base flood level with hydrostatic-load-resistant walls, certified by an engineer or architect. 160(C)(4). 190: they must be elevated so the lowest floor is at or above the base flood elevation and be securely anchored to a permanent foundation system.
Violations & Fines
Failing to elevate a new or substantially improved structure as §15.40.160(C) requires is enforced through the chapter's general compliance rule: any noncompliant construction or alteration is a misdemeanor under §15.40.080, and the city can also pursue other lawful action to remedy the deficiency, including withholding the elevation certification the floodplain administrator must keep on file under §15.40.150(D).
Frequently Asked Questions
How high must my home's floor be above flood level in Whittier?
What if my property is in Zone AH or AO instead?
Can I use vents instead of raising a garage or crawl space?
Sources & Official References
Other rules in Whittier
California rules heatmap·Compare Whittier to another location·View the California environmental rules overview
See something wrong?
Help us keep this page accurate. If you notice an error or outdated information, let us know.
Flood Elevation Requirements in Nearby Cities
How other cities in Los Angeles County handle flood elevation requirements.