Wildfire Zones: Costa Mesa vs Irvine
How do wildfire zones rules compare between Costa Mesa, CA and Irvine, CA?
Irvine has fewer restrictions than Costa Mesa.
Costa Mesa, CA
Orange County
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.
View full Costa Mesa rules →Irvine, CA
Orange County
Irvine adopted updated Fire Hazard Severity Zone maps in 2025, expanding Moderate, High, and Very High designations into multiple communities. Properties in FHSZ areas face enhanced building standards and defensible space requirements.
View full Irvine rules →Key Facts Comparison
| Fact | Costa Mesa | Irvine |
|---|---|---|
| Ordinance | No. 25-015 (Aug 2025) | - |
| Zones | Very High, High, Moderate | Moderate, High, Very High |
| Building Code | CBC Ch. 7A / CRC R327 | CBC Chapter 7A in VHFHSZ |
| Disclosure Required | CC §1103 NHD Statement | - |
| VHFHSZ Areas | Canyon communities | - |
| FHSZ Map | - | Updated 2025, effective July 2025 |
| Expanded Areas | - | 8+ communities added |
| Defensible Space | - | 100 ft required in FHSZ |
Highlighted rows indicate differences between cities.
Costa Mesa FAQ
Is my unincorporated Orange County property in a wildfire zone?
Check the OC Fire Hazard Severity Zones Map adopted under Ordinance No. 25-015. Most canyon and hillside communities (Trabuco Canyon, Silverado, Modjeska, Santiago Canyon) are classified as Very High Fire Hazard Severity Zones.
What building requirements apply in Orange County wildfire zones?
Properties in Very High Fire Hazard Severity Zones must use fire-resistive construction per California Building Code Chapter 7A, including ignition-resistant materials, ember-resistant vents, and fire-rated roofing.
Irvine FAQ
Is my Irvine home in a wildfire zone?
Check the city's Fire Hazard Severity Zone Map. The 2025 update expanded zones into Orchard Hills, Woodbury, Portola Springs, Quail Hill, Turtle Rock, and other communities.
What building requirements apply in fire zones?
Properties in Very High FHSZ must meet CBC Chapter 7A standards for ignition-resistant construction, including Class A roofing and fire-resistant walls.
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