Wildfire Zones: Hesperia vs Rialto
How do wildfire zones rules compare between Hesperia, CA and Rialto, CA?
Rialto has fewer restrictions than Hesperia.
Hesperia, CA
San Bernardino County
Updated CAL FIRE/OSFM Fire Hazard Severity Zone maps significantly expanded Very High Fire Hazard Severity Zones (VHFHSZ) in Hesperia effective July 22, 2025. Properties in VHFHSZ must comply with Chapter 7A of the California Building Code (WUI ignition-resistant construction) and PRC §4291 defensible space.
View full Hesperia rules →Rialto, CA
San Bernardino County
Most of Rialto is in a Local Responsibility Area (LRA) Moderate / Non-VHFHSZ classification, but the northern foothill / Cajon Pass overlay touches CAL FIRE State Responsibility Area (SRA) Very High Fire Hazard Severity Zones (VHFHSZ). Properties within these zones face Cal. Public Resources Code §4291 100-ft. defensible space, Cal. Government Code §51182 vegetation requirements, and Cal. Building Code Chapter 7A WUI construction standards.
View full Rialto rules →Key Facts Comparison
| Fact | Hesperia | Rialto |
|---|---|---|
| Zone Designation | Expanded VHFHSZ effective July 22, 2025 | - |
| Authority | CAL FIRE/OSFM + SB County Fire (LRA) | - |
| Building Standard | CBC Chapter 7A (WUI construction) | - |
| Defensible Space | 100 ft per PRC §4291 | - |
| Zone 0 | 0–5 ft ember-resistant (AB 3074) | - |
| Disclosure | AB 38 buyer disclosure required in VHFHSZ | - |
| Most of city | - | LRA Moderate / unzoned |
| Northern foothill / Cajon Pass | - | SRA Very High Fire Hazard Severity Zone |
| Defensible space | - | 100 ft. (PRC §4291 / Gov. Code §51182) in VHFHSZ |
| New construction in WUI | - | Cal. Building Code Ch. 7A required |
| AB 38 sale disclosure | - | Required for VHFHSZ properties |
Highlighted rows indicate differences between cities.
Hesperia FAQ
Is my Hesperia property in a wildfire zone?
Possibly. Updated VHFHSZ maps took effect July 22, 2025 and expanded coverage significantly. Check the CAL FIRE OSFM FHSZ viewer or City of Hesperia Building & Safety, and review Hesperia Information Bulletin IB-25-002.
What construction standards apply in VHFHSZ?
California Building Code Chapter 7A: ignition-resistant exterior walls, Class A roof, dual-pane tempered glass windows, ember-resistant vents (1/16–1/8 in mesh), protected eaves, and non-combustible decking near structures.
Do I have to disclose VHFHSZ when selling?
Yes. AB 38 (2019) requires sellers to disclose VHFHSZ designation to buyers and, for homes built before 2010, provide a home-hardening disclosure as part of the Natural Hazard Disclosure Statement.
What is Zone 0?
Zone 0 is the 0–5 ft ember-resistant zone immediately around a structure, mandated by AB 3074 (2020) and regulated by the California Board of Forestry. Combustible materials (wood mulch, fences attached to the home, stored items) must be removed.
Rialto FAQ
How do I know if my Rialto property is in a wildfire zone?
Check the official CAL FIRE FHSZ Viewer (osfm.fire.ca.gov/fhsz). Most Rialto urban parcels are LRA Moderate; only northern/foothill parcels near Lytle Creek and the Cajon Pass are SRA VHFHSZ.
What do I have to do if I'm in a VHFHSZ?
Maintain 100 ft. defensible space per PRC §4291, comply with Ch. 7A construction standards for new builds/remodels, and disclose the zone at any sale per AB 38.
Does Rialto Fire inspect for defensible space?
Yes — Rialto Fire conducts annual weed-abatement inspections of all parcels under Mun. Code §15.28.060; CAL FIRE separately inspects SRA parcels for PRC §4291 compliance.
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