California’s Zone 0 ember-resistant zone requirements call for a five-foot noncombustible buffer around every building and structure on your property, including the outer edge of any attached deck. The rule comes from Assembly Bill 3074 and lives in Public Resources Code section 4291. New construction in high and very high fire hazard severity zones must comply as of early 2026, and existing homes have three years from that date to catch up.
Who Has to Comply and When
Zone 0 applies to buildings and structures in State Responsibility Areas and in fire hazard severity zones designated by the Director of Forestry and Fire Protection. That covers most rural and wildland-adjacent properties in California, plus suburban areas mapped as high or very high fire hazard severity zones by local agencies. If your home sits in one of those zones, every structure on the parcel needs its own five-foot ember-resistant perimeter.
The timing splits two ways. New construction must meet Zone 0 standards now that the Board of Forestry and Fire Protection has finalized its regulations and fuels management guidance, which happened in early 2026. Existing homes get three additional years from that effective date, and the statute directs the Board to allow staged implementation so you can spread the cost.1California Legislative Information. California Public Resources Code PRC 4291
One wrinkle on enforcement: PRC 4291 says the department will not change its defensible space inspection practices to implement Zone 0 until the State Fire Marshal certifies the Legislature has appropriated enough resources.1California Legislative Information. California Public Resources Code PRC 4291 Waiting on that is still a gamble. Early compliance positions you for insurance discounts and avoids a scramble when enforcement ramps up.
How the Five Feet Are Measured
Measure from the outer edge of any attached projection, not from the exterior wall. The statute defines “structure” to include attached decks for Zone 0 purposes, and the same logic applies to porches, covered patios, and stairways.1California Legislative Information. California Public Resources Code PRC 4291 Pick whichever attached feature sticks out furthest and measure five feet outward from there. The result is a continuous noncombustible band wrapping the whole footprint.
Ground Cover Within the Zone
Everything on the ground inside the five feet must be noncombustible. CAL FIRE’s guidance identifies gravel, decomposed granite, pavers, and concrete as the right materials, along with bare mineral soil.2CAL FIRE. Defensible Space The idea is simple: leave nothing on the ground that an ember can light.
Organic mulch is the most common failure point. Shredded bark, wood chips, and rubber mulch all catch embers easily and can smolder against siding for several minutes before producing flame. Swapping mulch beds for rock or gravel inside the five-foot ring is usually the single most impactful change you can make, and the California Department of Insurance lists it as one of the ten actions that qualify for a wildfire premium discount.3California Department of Insurance. Safer from Wildfires
Vegetation Rules
Current guidance from state fire agencies requires removing all vegetation within five feet of the structure. That includes grass, ground covers, plants, shrubs, and bushes, whether living or dead.4California Governor’s Office of Emergency Services. Defensible Space – Zones 0, 1, and 2 Even well-irrigated, nominally fire-resistant plants can ignite under extreme heat or after a long drought, and they form a fuel bridge between the wildland and your walls.
The statute directs the State Fire Marshal to identify vegetation types that should be excluded from the ember-resistant zone based on their likelihood of causing structural ignition.1California Legislative Information. California Public Resources Code PRC 4291 Limited exceptions for low-growing succulents or similar fire-resistant species in noncombustible containers may emerge as rules develop. For now, treat the five-foot zone as a vegetation-free area. Prune any tree branches that overhang the roofline or come within five feet of the structure so fire cannot climb into the canopy or reach the eaves.
Fences, Decks, and the Wall Base
A wooden fence attached to your house behaves like a fuse. Fire traveling along a fence can reach the siding within seconds. Create a noncombustible break where the fence meets the structure: a metal gate, the first five feet of fencing replaced with steel or wrought iron, or a masonry section. The Department of Insurance describes a wood fence as something that “can act like a candle wick leading fire straight to your home.”3California Department of Insurance. Safer from Wildfires
The space under decks, porches, and raised floors needs the same discipline. Clear vegetation and combustible items down to concrete, gravel, or bare soil.5Ready for Wildfire. Defensible Space Firewood, plastic furniture, cardboard, and lawn equipment stacked under a deck create a concentrated fuel load that traps embers and can light the joists above.
On top of the deck, minimize combustible items like furniture and planters within the zone.5Ready for Wildfire. Defensible Space Propane tanks and grills deserve their own treatment. Zone 1 rules require ten feet of bare-soil clearance around propane tanks, with no flammable vegetation for another ten feet, so moving tanks well away from the house is the practical move regardless of which zone line they sit on.
The Six-Inch Noncombustible Wall Base
The Safer from Wildfires program recommends at least six vertical inches of noncombustible material at the base of every exterior wall, measured from the ground up or from any attached horizontal surface such as a deck. Brick, stone, fiber-cement siding, and concrete all qualify.3California Department of Insurance. Safer from Wildfires Embers collect where vertical walls meet horizontal surfaces, and a small strip of combustible siding at the base is enough to start a fire. This retrofit is straightforward and counts toward one of the insurance discount categories.
Vents and Openings
Embers do not just land on the ground. They get drawn into attic vents, crawlspace openings, and eave soffits, where they can smolder undetected until the house is burning from the inside. California Building Code Chapter 7A requires that ventilation openings resist the intrusion of burning embers and flame.6UpCodes. California Building Code Chapter 7A – SFM Materials and Construction Methods for Exterior Wildfire Exposure Vents must either be approved wildfire-resistant products listed by the State Fire Marshal or meet the ASTM E2886 testing standard.
At a minimum, cover vent openings with noncombustible, corrosion-resistant metal mesh sized between 1/16 and 1/8 inch. Standard quarter-inch screens are too coarse to stop embers. Fiberglass and plastic mesh will melt. Mesh alone is not enough for eaves and cornices, because embers can pile against the screen and radiate heat inward; baffled vents or enclosed eave soffits do more. Gable-end vents are especially vulnerable because of their size and vertical orientation, and replacing them with models that have passed ASTM E2886 testing is the preferred fix.3California Department of Insurance. Safer from Wildfires
Ongoing Maintenance
Zone 0 is not a one-time project. Wind deposits dead leaves, pine needles, and dry grass into the perimeter and onto the roof constantly, and those fine fuels ignite easily. CAL FIRE’s guidance calls out clearing dead plants, weeds, and debris from the roof, gutters, deck, porch, and stairways.2CAL FIRE. Defensible Space
Gutters need special attention. A gutter packed with dry leaves is a trough of kindling running along your roofline. Noncombustible gutter guards help but do not replace periodic cleaning. Inspect the full five-foot perimeter at least seasonally, and more often in fall and before fire season. The homes that burn are usually not the ones where the zone was never created; they are the ones where maintenance slipped.
Penalties, Discounts, and Selling the Home
Violating PRC 4291’s defensible space requirements is an infraction with a fine between $100 and $500. A second violation within five years raises the minimum to $250. A third within five years is a misdemeanor with a minimum $500 fine, and CAL FIRE can perform or contract the compliance work and bill you. If you fix the problem before sentencing and show the court proof, the judge may reduce the fine to $50.7California Legislative Information. California Public Resources Code PRC 4291.1
The larger financial issue is insurance. California’s Sustainable Insurance Strategy requires carriers to factor wildfire safety into their rates, and the Department of Insurance’s Safer from Wildfires program sets out ten specific actions tied to discounts. Zone 0 compliance covers several of them: the five-foot ember-resistant zone itself, noncombustible fencing, ember-resistant vents, enclosed eaves, the six-inch noncombustible wall base, and cleared space under decks.3California Department of Insurance. Safer from Wildfires California FAIR Plan dwelling fire policyholders who complete all twelve discount criteria may see up to 16.4% off the wildfire portion of their premium.8California FAIR Plan. Wildfire Hardening Discounts for Dwelling Fire and Commercial Policies
Selling adds its own layer. If you sell a home in a high or very high fire hazard severity zone, California Civil Code section 1102.19 requires you to give the buyer documentation showing the property complies with PRC 4291’s defensible space requirements, an obligation in effect since July 1, 2021. If your city or county has a local compliance inspection ordinance, follow it. If not and a state or local agency provides inspections, the documentation must come from an inspection within six months of listing. If you cannot get documentation before closing, you and the buyer can sign a written agreement giving the buyer one year from close of escrow to obtain it.9California Legislative Information. California Civil Code CIV 1102.19
How Zone 0 Fits With Zones 1 and 2
Zone 0 is the innermost of three defensible space zones under PRC 4291, and the rules differ at each distance. Knowing where Zone 0 ends keeps you from applying its stricter standards where they do not apply, and from assuming the looser standards of Zone 1 cover the first five feet.
- Zone 0 (0–5 feet) is the ember-resistant zone: noncombustible ground cover, no vegetation, cleared under decks, noncombustible fencing where it meets the home.
- Zone 1 (5–30 feet) is the lean, clean, and green zone. Landscaping is allowed but must be well maintained with spacing between trees and shrubs. Remove dead leaves, pine needles, and debris. Keep trees trimmed at least ten feet from chimneys, clear flammables from under any decks or balconies, and give propane tanks and outbuildings ten feet of clearance to bare soil.
- Zone 2 (30–100 feet) is the reduced fuel zone. Mow grass to four inches or less, space trees horizontally, prune lower branches up, and remove dead vegetation and fallen leaves.
All three zones extend only to the property line if the lot is smaller than the stated distance.10Board of Forestry and Fire Protection. Defensible Space Zones 0, 1 and 2 Zone 0 is the most restrictive, and because the area is small it is often the least expensive to implement. It is also the highest-impact zone, since embers cause most home ignitions during wildfires and clearing fuel within five feet of the structure is the single most effective step you can take.