12 min read · Fire-Resistant
The first five feet around a California home are now regulated space. On **August 19, 2026**, the Board of Forestry and Fire Protection approved the final Zone 0 rule package — the ember-resistant zone that AB 3074 ordered back in 2020 and that two later laws and a Governor's executive order pushed to completion. It is not yet in force: the package still goes to the Office of Administrative Law for review and to the Secretary of State for publication, and the compliance clock starts from that publication rather than from the vote. But the substance is settled, the phase-in is written, and the years of "still a draft" are over. This guide covers what the approved rule actually requires in the first five feet, the two-phase timeline for existing homes, the sequencing traps for landlords and sellers, and the part most Zone 0 coverage skips: the wall itself, where your siding meets the fuel the rule is trying to remove.
What Zone 0 is and where it came from
Zone 0 is the ember-resistant zone covering the first **0–5 feet** out from a structure — the strip where wind-driven embers land, lodge, and start the ignitions that burn homes down long before any flame front arrives. It was created by AB 3074 (2020), which amended California's defensible-space statute (Public Resources Code §4291) to add a third, most-intense tier to the familiar 30-foot and 100-foot framework, and directed the Board of Forestry and Fire Protection to write the regulations defining it. Three later actions kept the pressure on: SB 504 (2024), Governor Newsom's Executive Order N-18-25 issued after the January 2025 Los Angeles fires, and AB 1455 (2025), chaptered October 13, 2025, which wrote the compliance sequencing directly into statute. The science behind the five-foot figure is the same research base behind the IBHS and CAL FIRE hardening programs — post-fire investigation consistently shows embers igniting mulch, vegetation, fences, and stored combustibles against the wall, then the wall itself. Zone 0 is the regulatory version of a conclusion fire researchers reached years ago: the material touching your house is part of your house.
Where the rule stands — a date-stamped status check
Here is the honest status, stamped **as of late August 2026**, because this is a moving regulation and undated claims about it age badly. The Board of Forestry **approved the final Zone 0 rule package on August 19, 2026**, after roughly fifteen months of workshops, site visits, and public comment. What has *not* happened yet is the last procedural step: the package goes to the **Office of Administrative Law** for legal review, with a short public comment window, and then to the **Secretary of State** for publication. The compliance timelines below run from that publication date, not from the August vote — so until publication is confirmed, treat any specific effective date you read (including in news coverage) as an expectation rather than a fact. Two things you can rely on now: the requirements themselves are settled, and the phase-in is generous by design. The Board's own summary is explicit that implementation "will prioritize education and outreach," with inspectors focused on helping homeowners identify issues and demonstrate measurable progress over a five-year period rather than on immediate penalties. Check the Board of Forestry's defensible-space page for the current status before you make decisions on dates — including anything on this page.
Who the rule applies to
Zone 0 reaches the state's highest-exposure homes, and the scope is defined by two designations rather than by county lines. It applies to all property owners in the **State Responsibility Area** (the CAL FIRE-protected lands governed by PRC §4291) and to parcels mapped **Very High Fire Hazard Severity Zone within a Local Responsibility Area** (Gov. Code §51182). That second category matters more than it used to: CAL FIRE and the State Fire Marshal released updated Local Responsibility Area Fire Hazard Severity Zone maps in 2025 — the first comprehensive revision since 2007 — and local agencies are required to adopt them by ordinance. A parcel that was outside the Very High tier under the old maps may be inside it under the new ones, which means the 2025 remap quietly decided who Zone 0 applies to. If you are not certain which designation your address carries, check the state's Fire Hazard Severity Zone viewer and your county's adopted map before assuming the rule does or does not reach you; our California siding code and fire-zone reference explains how the designations connect to the building requirements that follow from them.
What the approved rule requires in the first five feet
The approved package divides Zone 0 into two bands rather than treating all five feet identically — a change that makes it easier to comply with and easier to describe. Nearest the building is a noncombustible **"safety zone"** whose width flexes with your eaves: a 12-inch eave triggers a 12-inch safety zone, a 36-inch eave triggers a 36-inch one, with a **one-foot minimum** where eaves are shallow, plus a vegetation-free buffer **two feet from windows, glass doors, and vents** and **five feet around attached decks, stairs, and pergolas**. Outside that, running to the five-foot line, is a **low-combustibility zone**: no combustible mulch, wood chips, fallen leaves and needles, firewood, or stored wood, and none of that on roofs or in gutters either. Living landscape is not banned. Well-maintained herbaceous plants and flowers are allowed outside the buffers in spaced groupings, low ground covers are allowed, lawn is allowed if kept mowed to **three inches**, and potted plants are allowed in noncombustible containers that are easily moveable and **no taller than 18 inches**. Existing trees may stay, subject to maintenance: dead wood removed, ladder fuels cleared from the **lower six feet of large trees or the lower third of small ones**, branches kept **five feet above roofs** and **ten feet from chimneys** — though **no new trees may be planted in Zone 0** once the rule takes effect, for consistency with the state's wildland-urban interface building standards. Fences get their own rule: a **five-foot noncombustible section is required where a fence attaches to the home**, no new combustible fences or gates are permitted within Zone 0, and repairs to existing fences remain allowed.
The two-phase timeline, and the traps for landlords and sellers
For **new construction**, compliance is required as soon as the regulation takes effect — there is no phase-in. For **existing homes**, the rollout runs in two phases from the effective date. A short list of items applies **immediately** to align with laws already on the books: combustible debris off roofs and out of gutters, dead branches removed, and branches cleared ten feet from chimneys. **Phase 1, within three years**, covers the bulk of the work most homeowners picture — removing firewood, mulch, and wood chips from the five-foot strip, cleaning gutters, removing dead and dying plants, trimming trees to the rule, and adjusting plantings to what is allowed. **Phase 2, within five years** and with the specific timeline assigned by your local jurisdiction, completes the under-eave safety zone, replaces combustible gates, and brings sheds and fencing into line. Two statutory wrinkles from AB 1455 are easy to miss and expensive to miss: **rental properties must comply immediately** upon the new-structure effective date rather than on the three-year phase-in, and **properties offered for sale must comply upon sale or three years after the new-structure deadline, whichever comes first**. If you own a rental in a fire zone, or expect to sell within a few years, your clock is materially shorter than your neighbor's — see our pre-sale siding replacement guide and the rental property siding cost guide for how that tends to reshape a project's timing.
The siding angle: where the wall meets the fuel
Most Zone 0 coverage treats this as a landscaping rule, and for your house's walls that reading is basically correct — **Zone 0 does not require you to re-side your home in noncombustible material**. It regulates what sits in the strip, not what the strip is up against. Being precise about that matters, because a contractor who tells you Zone 0 forces a fiber-cement re-side is either confused or selling. There are two real exceptions and one real relationship. The exceptions: **sheds and outbuildings located within Zone 0 must have noncombustible exterior roofs and walls**, and the rule adds a definition of "noncombustible" drawn from the 2025 California Wildland-Urban Interface Code — so the same standard that governs cladding on a WUI-exposed house now governs the garden shed five feet from it. The relationship is the one we would actually point you at: the zone and the wall are two halves of one ignition sequence. Three wall details do most of the work. **Cladding-to-grade clearance** — siding that runs down into soil or mulch wicks moisture in normal years and meets ground fire directly in bad ones; our cladding-to-grade guide covers the detail. The **base of wall** — the bottom six vertical inches is the surface radiant heat and surface flame reach first, which is why both the IBHS standard and California's Safer from Wildfires framework single out a noncombustible wall base as its own line item. And **attachments** — a combustible fence or gate tied into the wall defeats both the zone and the cladding, which is precisely why the approved rule now requires that five-foot noncombustible fence section. A wall that is noncombustible from grade up, with a compliant zone in front of it, removes the ignition sequence Zone 0 targets. Neither half makes a home fireproof — nothing does — but together they take away the most common way homes ignite.
Local variation: your jurisdiction may not look like the state rule
The approved package deliberately leaves room for local judgment, and this is the part most summaries omit. **Local fire agencies may authorize alternative practices** based on local variation — geography and topography, fire risk, lot size, response resources, structure composition, or compliance with the wildland-urban interface code — provided those alternatives deliver "substantially similar practical effects" to the state rule. The agency has to support the variation with a finding that it is equally effective, and the variation requires approval by the governing body, meaning a city council or county board of supervisors. One example the Board itself gives is directly relevant to anyone who has already hardened their exterior: an inspector may consider **the use of fire-safe construction or building materials** when applying the rule. That is not a promise, and it is not a trade — nobody should read it as "noncombustible siding buys you a landscaping exemption." But it does mean the practical answer in Grass Valley may differ from the practical answer in El Dorado Hills or Truckee, and that the authority to ask is your local fire agency, not a state webpage. Confirm your jurisdiction's position before you plan work around an assumption, the same way you would confirm a permit requirement rather than assume the statewide default applies.
How a re-side coordinates with Zone 0 — and why acting now still makes sense
If you are already planning exterior work, Zone 0 is a coordination opportunity rather than a separate project. A re-side is the one moment the base of the wall is open, the grade relationship is adjustable, fence attachments are exposed, and the crew is on site with the tools to change all three. Doing the Zone 0-adjacent wall details then — grade clearance, a noncombustible wall base, a noncombustible fence transition, ember-resistant vent treatment — costs a fraction of what it costs as a standalone visit later. As for waiting: the physics are not on a rulemaking schedule. Embers ignite the five-foot strip today, whether or not a regulation says so, and CAL FIRE and the UC ANR Fire Network have recommended an ember-resistant zone and noncombustible wall materials for years on post-fire evidence alone. The insurance system is not waiting either: California's Safer from Wildfires framework already recognizes the five-foot ember-resistant zone and the noncombustible wall base as discount-eligible mitigation — carrier-dependent, never guaranteed, but recognized now — and if you have been non-renewed, documented Zone 0-style work belongs in the requote file our non-renewal playbook describes. Doing the work early means doing it on your schedule, folded into projects you were doing anyway, rather than in year three alongside every other homeowner in your severity zone.
What the approved Zone 0 rule requires vs. what a re-side project can address
| Zone 0 element | What the approved rule requires | What a re-side can address |
|---|---|---|
| Combustible mulch, wood chips, stored wood | Removed from the 0–5 ft strip (Phase 1, within 3 years) | Not a siding scope — but we flag it during scoping and coordinate grade transitions |
| Under-eave safety zone | Noncombustible, width flexing with eave width, 1 ft minimum (Phase 2, within 5 years) | Soffit and eave detailing, and a noncombustible wall base at the same time |
| Fence or gate attached to the house | A 5 ft noncombustible section where the fence meets the structure (Phase 2) | The wall-side transition and flashing where the fence attachment meets the cladding |
| Sheds and outbuildings inside Zone 0 | Noncombustible exterior roofs and walls | Re-cladding an outbuilding in noncombustible material, same crew and visit |
| Cladding-to-grade clearance | Not directly regulated by Zone 0 | Manufacturer-spec ground clearance — the detail that fails most often at the wall base |
| Wall cladding on the house itself | Not required to be noncombustible by Zone 0 | Where the WUI code or your exposure calls for it, noncombustible cladding and ember-resistant venting |
Key takeaways
- The Board of Forestry APPROVED the final Zone 0 rule package on August 19, 2026. It is not yet in force — it still goes to the Office of Administrative Law and the Secretary of State, and the compliance clock runs from publication.
- Scope: all State Responsibility Area parcels (PRC §4291) plus Very High Fire Hazard Severity Zone parcels in Local Responsibility Areas (Gov. Code §51182). The 2025 LRA map update changed who that includes.
- Zone 0 splits into a noncombustible 'safety zone' that flexes with your eave width (one-foot minimum) and a low-combustibility zone out to five feet.
- New construction complies on the effective date. Existing homes get Phase 1 within three years and Phase 2 within five — but rentals comply immediately, and homes for sale comply at sale or three years, whichever comes first.
- Zone 0 does NOT require noncombustible siding on your house. It does require noncombustible roofs and walls on sheds and outbuildings inside the zone, and a five-foot noncombustible fence section where a fence meets the home.
- Local fire agencies may approve alternative practices with substantially similar effect — so confirm your jurisdiction's position rather than assuming the statewide default.
FAQ
Quick Answers
Almost. The Board of Forestry and Fire Protection approved the final rule package on August 19, 2026, which was the substantive decision. The package still requires Office of Administrative Law review and publication by the Secretary of State before it takes effect, and every compliance deadline runs from that publication rather than from the August vote. Treat specific effective dates in news coverage as expectations until publication is confirmed on the Board of Forestry's own page.
No. Zone 0 regulates what occupies the first five feet around a structure — mulch, plants, stored combustibles, fences, sheds — not the cladding on your house. Anyone telling you the rule forces a fiber-cement re-side is overstating it. The two places the approved rule does reach building materials are sheds and outbuildings inside the zone, which must have noncombustible exterior roofs and walls, and the five-foot noncombustible section now required where a fence attaches to a home.
It flexes with your eaves. A 12-inch eave produces a 12-inch safety zone; a 36-inch eave produces a 36-inch one. Where eaves are shallow the safety zone is still a minimum of one foot, and the vegetation-free buffer extends two feet from windows, glass doors, and vents and five feet around attached decks, stairs, and pergolas. Beyond the safety zone, out to five feet, the low-combustibility rules apply instead.
Existing trees can stay, with maintenance: dead wood removed, ladder fuels cleared from the lower six feet of a large tree or the lower third of a small one, branches five feet above the roof and ten feet from chimneys. No new trees may be planted in Zone 0 once the rule takes effect. Herbaceous plants and flowers are allowed in spaced groupings outside the buffers, low ground covers are allowed, lawn is allowed if mowed to three inches, and potted plants are allowed in noncombustible containers no taller than 18 inches.
No. Under AB 1455 (2025), rental properties must comply immediately upon the new-structure effective date rather than on the three-year Phase 1 schedule. Properties offered for sale must comply upon sale or three years after the new-structure deadline, whichever comes first. If you own a rental or expect to sell, your timeline is materially shorter than an owner-occupant's.
Not exactly. Local fire agencies may authorize alternative practices based on local geography, fire risk, lot size, response resources, structure composition, or wildland-urban interface code compliance, provided the alternative delivers substantially similar practical effects, the agency makes a finding to that effect, and the governing body approves it. That means the practical answer can differ between counties, and your local fire agency is the authority to ask.
Possibly, but never assume it. The Board's own summary notes that a local alternative practice might involve an inspector considering the use of fire-safe construction or building materials. That is discretion available to a local agency, not an exemption you can claim. What documented hardening more reliably does is strengthen your insurance position — California's Safer from Wildfires framework recognizes both the five-foot ember-resistant zone and a noncombustible wall base as mitigation, though any discount is carrier-dependent and never guaranteed.
Sources
Authoritative references
- California Board of Forestry & Fire Protection — Defensible Space Zones 0, 1, and 2 (Zone 0 rulemaking)
- Board of Forestry — Summary of Zone 0 Regulation Language, August 2026 rule package (approved August 19, 2026)
- AB 3074 (2020) — bill text creating the ember-resistant zone (amending PRC §4291)
- SB 504 (2024) — ember-resistant zone amendments to PRC §4291
- AB 1455 (2025, chaptered Oct 13 2025) — Zone 0 compliance sequencing for new, existing, rental, and for-sale property
- Public Resources Code §4291 — defensible space in the State Responsibility Area
- Government Code §51182 — defensible space in Very High Fire Hazard Severity Zones (LRA)
- 2025 California Wildland-Urban Interface Code (Title 24, Part 7) — the source of the rule's 'noncombustible' definition
- CAL FIRE Ready for Wildfire — defensible space & the 0–5 ft ember-resistant zone
- UC ANR Fire Network — Siding (vinyl combustibility & sheathing dependence; noncombustible options)
External links to government, code, and manufacturer sources. Sierra Siding is not affiliated with these organizations; references are provided for verification.