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 §4291. Real estate sellers must provide a Natural Hazard Disclosure Statement identifying fire hazard zones per California Civil Code §1103.
Non-compliance with building code fire-resistive requirements may result in permit denial or stop-work orders. Defensible space violations carry fines of $100–$2,000 under PRC §4291. Failure to provide fire hazard disclosure in real estate transactions may result in civil liability.
Costa Mesa, CA
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Side-by-side rule comparisons with other cities in Orange County.
See how other cities in Orange County handle wildfire zones.
See how Costa Mesa's wildfire zones rules stack up against other locations.
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