Yolo County, CA Environmental Rules: Flood Zones (2026)
FEMA flood zone rules in Yolo County, CA, also called floodplain regulations or special flood hazard area (SFHA) rules, determine flood insurance requirements and elevation standards for new construction.
Key Facts
- Permit required
- Development Permit before any work in flood hazard area
- Elevation standard
- 1 ft above base flood elevation (AE/AH/A1-30)
- Flood vent size
- 1 sq in net area per sq ft enclosed
- Appeal deadline
- 15 days to Planning Commission
- Enforcing officer
- Floodplain Administrator
- Enforcement
- Misdemeanor; permit suspension or revocation
Summary
Any construction or development inside a Yolo County special flood hazard area needs a Development Permit before work begins, under Sec. 8-4.403. New and substantially improved homes must have their lowest floor elevated at least 1 foot above the base flood elevation, and the county's Floodplain Administrator reviews plans, grading, and utility locations.
A Development Permit shall be obtained before any construction or other development begins within any area of special flood hazards established in Section 8-4.302. Application for a Development Permit shall be made on forms furnished by Yolo County.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: 2026 S-21: Supplement 2026 S-21 includes: Local legislation current through Ord. 1584, effective June 25, 2026).
Full Breakdown
Sec. 302," with the application made on county forms and including plans showing elevations, drainage, utility locations, the regulatory floodway, and the base flood elevation. Sec. 501(c)(1) sets the elevation standard: in AE, AH, and A1-30 zones the lowest floor, including any basement, must be elevated at least 1 foot above the base flood elevation, certified before framing by a registered engineer or licensed land surveyor and verified by the County Building Official. In an AO zone the structure must clear the FIRM's depth number by at least 1 foot, or 3 feet above the highest adjacent grade if no depth number is shown.
Nonresidential buildings may instead be floodproofed and certified watertight by a registered civil engineer or architect under Sec. 501(c)(2). Enclosed areas below the lowest floor used only for parking, access, or storage need automatic flood-venting: a minimum of two openings on different walls, with a combined net area of at least 1 square inch per square foot of enclosed area, and the bottom of each opening no higher than 1 foot above grade, per Sec. 501(c)(3). A Floodplain Administrator decision can be appealed to the Planning Commission within 15 days under Sec. 405, with a hearing set within 60 days.
Violations & Fines
Sec. 8-4.406 makes any violation of the flood damage prevention chapter a misdemeanor punishable under Title 1 of the County Code, and failure to correct a written notice of violation is itself deemed a public nuisance and a separate misdemeanor. The Floodplain Administrator can suspend or revoke a Development Permit for noncompliance, halting all work until the violation is remedied or a Board of Supervisors appeal is decided.
Frequently Asked Questions
Do I need a permit to build in a Yolo County flood zone?
How high must a new home be built in a flood zone?
What if I disagree with a Floodplain Administrator decision?
What happens if I develop in a flood zone without a permit?
Sources & Official References
Other rules in Yolo County
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