Wildfire Defense Guide
California defensible space runs in three zones from the house: Zone 0 (0–5 ft), Zone 1 (5–30 ft) and Zone 2 (30–100 ft). Fences matter most in Zone 0. The City of San Diego already sets Zone 0 fence rules under Fire-Rescue Standard D-2; the statewide rule adopted August 19, 2026 was not in effect as of September 2026.
Defensible space
The Three Zones, To Scale
A side view from the wall outward. Zone 0 is only the first 5 feet — see how small that is against the full 100 feet.
The 0–5 ft Zone 0 boundary in CAL FIRE defensible space guidance — where near-structure material choices matter most.
The lean, clean and green band of the CAL FIRE defensible-space model.
The outer reduced-fuel band of the CAL FIRE defensible-space model.
Resource Library
Guides & Tools
Expert resources to help you make informed decisions about fire-resistant fencing
Compliance Guide
Zone 0 Guide
Local ember-resistant guidance is evolving. Learn how near-structure material choices can help and how to prepare.
Financial Guide
Insurance & Coverage
Learn how fire hardening may affect coverage considerations. Discounts and eligibility vary by insurer and policy.
Technical Reference
ASTM Fire Ratings Explained
Complete guide to ASTM E84 flame spread index, E136 non-combustibility, and what Class A, B, and C ratings mean for local requirements.
Verified Data
Wildfire Loss Snapshot
Counts pulled from CAL FIRE DINS and state guidance
DINS inspections include structures within 100 meters of the fire perimeter
Source: CAL FIRE DINS
DINS counts reflect inspected structures within or near fire perimeters and may undercount total losses.
Official Resources
Government & Standards
Authoritative sources for California wildfire regulations
CAL FIRE
Fire Hazard Severity Zone Maps
Look up your property's official fire hazard zone designation
California Legislature
PRC Section 4291
Full text of California's Defensible Space law
Ready for Wildfire
Defensible Space Guide
CAL FIRE's official homeowner guide to creating defensible space
ASTM International
ASTM E84 Fire Test Standard
Official standard for surface burning characteristics testing
CA Building Standards
California WUI Code (Title 24, Part 7)
Ignition-resistant construction standards for wildfire zones. The CWUIC took effect Jan 1, 2026; it absorbed the provisions formerly in CBC Chapter 7A.
FEMA
Disaster Assistance
Federal assistance programs for wildfire victims
CAL FIRE dataset notes SRA FHSZ effective Apr 1, 2024 and LRA recommendations from 2007-2011 (source).
Local Regulatory Status
Has San Diego adopted Zone 0?
Where state and local Zone 0 rules stand as of September 2026 — and what still needs confirming with your AHJ.
Yes — the City of San Diego has already adopted Zone 0, ahead of the state. The city's requirement lives in San Diego Municipal Code (SDMC) §512.0604, part of the San Diego Wildland Urban Interface (SDWUI) Code. It defines Zone 0 and applies to new structures applying for a building permit on or after February 28, 2026, and to existing structures one year later, February 28, 2027. Its text does not use the word “fence”: the fence and gate rules come from Fire-Rescue Standard D-2 (new structures in a Very High Fire Hazard Severity Zone: new fences and gates in Zone 0 must be steel, aluminum, fiber cement board or masonry, with a 5-foot noncombustible transitional span where a fence attaches) and the Zone 0 Guidelines for Existing Structures. Our Zone 0 address checker shows whether an address point falls in a mapped Fire Hazard Severity Zone.
The statewide Zone 0 rule is different: the California Board of Forestry adopted it as emergency regulations on August 19, 2026 and submitted it to the Office of Administrative Law; as of September 2026 it is not yet in effect. The December 31, 2025 deadline set by Executive Order N-18-25 passed without adoption. The rule traces to AB 3074 (2020) and PRC §4291; the package adds 14 CCR §§1298.01–1298.04 for local-responsibility areas, where it covers occupied structures in Very High Fire Hazard Severity Zones, and amends §§1299.01–1299.03 for the State Responsibility Area, where it covers all structures. Once in effect, it bars combustible fences and gates attached to an occupied structure and new combustible fences and gates in Zone 0; existing structures get 3 years for the fence and gate rules, or up to 5 on a local fire agency’s timeline.
San Diego's Zone 0 Guidelines for Existing Structures include specific exceptions. Existing vinyl fencing (or fencing without combustible reinforcement) may stay within 5 feet if it runs parallel to the wall, sits no less than 4 feet from the structure, is in good condition and clear of debris, and has no vegetation between the fence and the structure. New parallel wood fencing is permitted only if it is Fire Retardant Treated Wood (FRTW), meets the vinyl conditions, and is listed in the California OSFM Wildland Urban Interface (WUI) Products Handbook. An existing fence attached perpendicular to the house needs a 5-foot noncombustible transitional span, and homeowners should attempt full compliance, including replacing noncompliant fences and gates, by February 28, 2029. The guidelines note that your insurer or the IBHS may not accept vinyl or FRTW within 5 feet.
| Rule | Status | Key dates |
|---|---|---|
| City of San Diego — SDMC §512.0604 (SDWUI Code), Standard D-2, Existing Structures guidelines | Adopted | New: Feb 28, 2026 · Existing: Feb 28, 2027 · Full-compliance target for existing homes: Feb 28, 2029 |
| Statewide — Board of Forestry (PRC §4291 / AB 3074) | Adopted, not yet in effect (emergency regulations, Aug 19, 2026) | Submitted to the Office of Administrative Law; no effective date as of September 2026. Existing structures: 3 years after it takes effect (up to 5 locally) |
Sources: City of San Diego Zone 0 Guidelines for Existing Structures (rev. 4/22/2026); San Diego Fire-Rescue Standard D-2; SDMC §512.0604; California Board of Forestry Zone 0 emergency action notice (Aug. 20, 2026). Confirm current status with your AHJ before final design decisions.
FAQ
Common Questions
What is defensible space for wildfire protection?
Defensible space is the area around a building kept clear or lean of fuel so a wildfire slows before it reaches the walls. California measures it in zones from the house: Zone 0 (0–5 ft, ember-resistant), Zone 1 (5–30 ft) and Zone 2 (30–100 ft). Fences matter most in Zone 0, where the City of San Diego already applies Fire-Rescue Standard D-2.
What fencing materials should I avoid in wildfire zones?
Wood fencing is combustible and can carry fire from vegetation to structures. Vinyl melts and can produce toxic fumes. Non-combustible options include aluminum, steel, gabion, and CMU block walls.
Where can I check my property fire hazard zone?
Enter the address in our Zone 0 address checker, which reads CAL FIRE's public Fire Hazard Severity Zone maps for San Diego County. The official designation comes from CAL FIRE's FHSZ maps and your local fire authority, which decides what applies to the parcel.
Has San Diego adopted Zone 0?
Yes. The City of San Diego adopted Zone 0 through San Diego Municipal Code (SDMC) §512.0604, part of the San Diego Wildland Urban Interface (SDWUI) Code; it applies to new structures applying for a building permit on or after February 28, 2026 and to existing structures one year later, on February 28, 2027. Fence and gate specifics come from Fire-Rescue Standard D-2 and the Zone 0 Guidelines for Existing Structures. The statewide Board of Forestry Zone 0 rule was adopted as emergency regulations on August 19, 2026 and is not yet in effect as of September 2026. Confirm current requirements with your AHJ.
Plan the First Five Feet
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