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Defensible space · California AB 3074

Zone Zero and your fence

California has added an ember-resistant zone within five feet of structures to its defensible space rules. If a fence or gate sits inside that five-foot band, the material it is made of matters. Here is what the rule covers, what it does not, and how to find out whether it applies to your address.

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0–5 ftEmber-resistant zone, measured from the structure
AB 30742020 law amending PRC §4291
VHFHSZApplies in State Responsibility Areas and Very High zones
VerifyConfirm your parcel with CAL FIRE and local fire

What the rule actually says

Public Resources Code section 4291 requires defensible space around structures in State Responsibility Areas and in Very High Fire Hazard Severity Zones within Local Responsibility Areas. Assembly Bill 3074, signed in 2020, added an ember-resistant zone covering the first five feet from the building and directed the State Board of Forestry and Fire Protection to adopt the detailed regulations, with later compliance dates for existing structures than for new construction.

The purpose is narrow and physical. In a wildfire, most structure ignitions come from wind-blown embers landing on or beside a building rather than from a advancing flame front. Removing combustible material from the first five feet is intended to deny those embers a place to catch.

For fencing, the practical consequence is straightforward: a fence or gate that sits within five feet of the house, garage, or attached deck is inside the ember-resistant zone, while a property-line fence farther away generally is not.

This page is general information, not a compliance determination. Regulatory detail and timelines under AB 3074 have continued to evolve. Confirm the requirements for your specific parcel with CAL FIRE and your local fire authority before making decisions.

Official references: CAL FIRE fire hazard severity zone maps · Chula Vista Fire Department

Fence materials, by combustibility

Whether a fence material qualifies as non-combustible is a property of the material, not a brand claim. Treated wood is the most common point of confusion.

Combustible materials

  • Wood: cedar, redwood, pine, mahogany
  • Vinyl and PVC
  • Wood-plastic composite
  • Bamboo and reed screening
  • Fire-retardant treated wood — reduced flame spread, but still a combustible material

Non-combustible materials

  • Ornamental steel and wrought iron
  • Powder-coated aluminum
  • Galvanized chain link
  • Masonry and concrete block
  • Gabion walls (stone in wire mesh)

Chula Vista Fence installs ornamental steel and wrought iron, aluminum, and galvanized chain link, and can replace only the sections inside the five-foot zone while tying into your existing fence beyond it.

How to check

Three steps to find out where you stand

Step 1

Check your hazard zone

Look up your parcel on the CAL FIRE fire hazard severity zone map. If it is not in a State Responsibility Area or a Very High severity zone, PRC §4291 defensible space requirements generally do not apply.

Step 2

Measure five feet

Measure outward from the house, garage, and any attached deck or stairs. Note which fence or gate sections fall inside that band. Usually it is a short run, not the whole fence.

Step 3

Confirm locally

Call the Chula Vista Fire Department or your local fire authority to confirm current requirements, timelines, and any local ordinance that goes beyond the state rule.

FAQ

Zone Zero questions

What is Zone Zero?
Zone Zero, formally the ember-resistant zone, is the area within five feet of a structure. California Assembly Bill 3074 (2020) amended Public Resources Code section 4291 to require this zone as part of defensible space, and directed the State Board of Forestry and Fire Protection to adopt implementing regulations. The intent is to prevent wind-driven embers from finding combustible material immediately against a building.
Does this apply to my property in Chula Vista?
The defensible space requirements in PRC 4291 apply to properties in State Responsibility Areas and in Very High Fire Hazard Severity Zones within Local Responsibility Areas. Much of urban western Chula Vista is not in a Very High severity zone, while some eastern and canyon-adjacent areas are. Check the official CAL FIRE hazard severity map and confirm with the Chula Vista Fire Department before assuming the requirement applies to your address.
Would I have to replace my whole fence?
Not typically. The ember-resistant zone is measured from the structure, so only fencing and gates within five feet of a building are implicated. Fencing along a property line farther than five feet from any structure is outside the zone. On many lots that means a short return section near the house rather than the full perimeter.
Which fence materials are non-combustible?
Steel and wrought iron, aluminum, galvanized chain link, masonry and concrete block, and gabion walls are non-combustible assemblies. Wood, vinyl and PVC, wood-plastic composite, and bamboo are combustible. Fire-retardant treated wood reduces flame spread but is still a combustible material, so it should not be assumed to satisfy a non-combustibility requirement.
When does it take effect, and what are the penalties?
AB 3074 set a phased approach, with the ember-resistant zone requirements tied to regulations adopted by the Board of Forestry and Fire Protection and applying later to existing structures than to new construction. Timelines and enforcement have continued to be refined through subsequent state action, and penalties for defensible space violations are set by statute and local ordinance. For current dates and enforcement in your area, verify with CAL FIRE and your local fire authority rather than relying on a contractor website.
Can you build a non-combustible fence?
Yes. Chula Vista Fence installs ornamental steel and wrought iron, aluminum, and galvanized chain link, all of which are non-combustible fence materials. We can also replace only the sections within five feet of the structure and tie them into your existing wood or vinyl fence beyond that point.

Need a non-combustible fence section?

We will walk the fence line with you, identify which sections sit inside the five-foot zone, and quote steel, aluminum, or chain link for just those runs if that is all you need.

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