Unincorporated Orange County contains extensive Very High Fire Hazard Severity Zones (VHFHSZ) as designated by CAL FIRE and adopted by the Board of Supervisors via Ordinance No. 25-015. Canyon and hillside communities face the strictest building and vegetation management requirements.
CAL FIRE released updated Fire Hazard Severity Zone (FHSZ) maps for unincorporated Orange County, classifying areas as Very High, High, or Moderate using the latest climate data, fire history, topography, and wildfire modeling. The Board of Supervisors adopted the updated map via Ordinance No. 25-015 on August 26, 2025. Unincorporated canyon communities including Trabuco Canyon, Silverado Canyon, Modjeska Canyon, Santiago Canyon, and Coto de Caza foothill areas are classified as Very High Fire Hazard Severity Zones. Buildings in VHFHSZ areas must be constructed using fire-resistive features per California Building Code Chapter 7A and California Residential Code Section R327, including ignition-resistant exterior materials, ember-resistant vents, and fire-rated roofing. Property owners must maintain 100 feet of defensible space per PRC Β§4291. Real estate sellers must provide a Natural Hazard Disclosure Statement identifying fire hazard zones per California Civil Code Β§1103.
Non-compliance with building code fire-resistive requirements may result in permit denial or stop-work orders. Defensible space violations carry fines of $100β$2,000 under PRC Β§4291. Failure to provide fire hazard disclosure in real estate transactions may result in civil liability.
Orange County, CA
Unincorporated Orange County exempts one small detached non-habitable accessory structure - a shed - per 7,200 square feet of building site area from accesso...
Orange County, CA
Carports in unincorporated Orange County are governed by Section 7-9-70.3(d) of the Codified Ordinances, which requires carports to comply with main-building...
Orange County, CA
Unincorporated Orange County allows the conversion of an existing garage, carport, or accessory structure into an accessory dwelling unit (ADU) under Section...
Orange County, CA
Unincorporated Orange County requires every pool/spa deeper than 18 inches to be enclosed by a barrier at least 60 inches (5 ft) high under California Health...
Orange County, CA
Unincorporated Orange County allows ADUs on any residentially zoned lot under OC Zoning Code (Title 7, Division 9) and California Government Code Β§65852.2 (A...
Orange County, CA
Orange County does not levy a general gross-receipts business tax in unincorporated areas; businesses obtain a county business license tied to zoning, while ...
See how Orange County's wildfire zones rules stack up against other locations.
Help us keep this page accurate. If you notice an error or outdated information, let us know.