California Board of Forestry Adopts Emergency “Zone 0” Regulations Under AB 3074
On August 19, 2026, the California State Board of Forestry and Fire Protection ("Board") adopted emergency regulations establishing an ember-resistant defensible space zone within five feet of qualifying structures, commonly called "Zone 0." The Board submitted the regulations to the Office of Administrative Law (OAL) on August 28, 2026, and OAL's five-calendar-day public comment period closed on September 2, 2026. OAL approval and filing are required before the regulations become effective.
The regulations add ember-ignition controls to California's existing defensible space framework. They establish standards for Very High Fire Hazard Severity Zones in Local Responsibility Areas (LRAs) and revise the rules for State Responsibility Areas (SRAs). Cities and districts may be affected both as owners or operators of facilities in covered areas and as agencies responsible for notice, inspection or enforcement.
Where the Regulations Apply
State Responsibility Areas
The amended SRA rules apply to buildings and structures throughout an SRA, regardless of whether a parcel is mapped as Moderate, High or Very High Fire Hazard Severity. Although SRAs generally exclude incorporated cities, a city or district may own or operate facilities outside city limits that fall within an SRA. Covered structures are broadly defined and may include combustible decks, stairs and pergolas, as well as public facilities such as treatment buildings, pump stations, equipment shelters, maintenance yards, warehouses, offices and park structures. There is an unresolved ambiguity in the defensible space regulations in SRAs regarding applicability to public agencies, although compliance may still be appropriate for safety, insurance, or operational reasons.
Local Responsibility Areas
The new LRA rules apply only to occupied structures in locally designated Very High Fire Hazard Severity Zones. They do not apply throughout Moderate or High LRA zones. The definition of an occupied structure includes a roofed structure used to support, enclose, shelter or protect people, animals or property. As a result, an equipment building may qualify even if employees are not regularly stationed there.
What Zone 0 Requires
Zone 0 generally extends five feet from the exterior wall, roof, attached deck, stairs or pergola, or to the property line if it is closer. A new structure on neighboring property, including an accessory dwelling unit, does not expand another owner's defensible space obligation. Subject to the implementation dates discussed below, the regulations generally require:
- Combustible materials and debris. Remove combustible mulch, wood chips, leaves, needles, bark and similar materials, subject to limited temporary exceptions for erosion control during construction or emergencies.
- Roofs and attached features. Keep roofs and gutters clear; remove vegetation and combustible items from beneath decks, balconies, pergolas and stairs; and do not store firewood within Zone 0.
- Trees and vegetation. Remove dead or dying branches and ladder fuels, maintain required separation from chimneys, roofs, eaves and walls, and keep vegetation away from vulnerable openings and attached features. Limited, maintained nonwoody plants may be allowed in portions of Zone 0 if they satisfy height, spacing, area and container standards.
- Fences and gates. Do not attach combustible fences or gates directly to a qualifying structure. New combustible fencing is prohibited within Zone 0, and attached or nearly attached fencing generally requires a five-foot noncombustible span. The rule allows the use of combustible materials for repairs to existing combustible fencing.
- Small outbuildings. An outbuilding of less than 120 square feet may be located within Zone 0 only if it is made entirely of materials meeting the regulation's noncombustible standard.
Local Alternatives in LRAs
The regulations allow an agency responsible for fire protection in an LRA to adopt alternative defensible space practices. The agency may not simply suspend or weaken Zone 0. An alternative must be adopted by ordinance and supported by a finding from the responsible fire protection agency that it will provide at least substantially similar practical effects. Local ordinances may also impose more stringent requirements.
Alternatives may account for local fire hazards, lot size, structure density, exterior construction, emergency response, geography, topography and compliance with Wildland-Urban Interface building standards. A defensible ordinance process should:
- Confirm authority. Verify that affected properties are in an LRA Very High Fire Hazard Severity Zone and identify the agency responsible for fire protection.
- Define the problem and proposed alternative. Identify the state practice being replaced, the locations or structures affected and the local conditions supporting a different approach.
- Build the record. Explain how the alternative will limit ember ignition, flame contact, radiant heat and fire transmission with substantially similar practical results. Support may include inspection data, fire behavior analysis, material standards, expert input and evidence of home-hardening measures.
- Obtain findings and adopt an ordinance. The responsible fire protection agency should make a written, evidence-based finding before the governing body acts. The ordinance should define its scope, preserve unaffected state requirements, establish compliance dates and assign inspection, documentation, enforcement and appeal responsibilities.
- Address implementation requirements. Complete the appropriate CEQA review, follow any separate process required for changes to state building standards, notify affected residents, train staff and retain the supporting record. Compliance with a valid local alternative protects a property owner from being treated as violating Government Code section 51182.
Government Code section 51183 separately permits an exemption for a structure with an entirely nonflammable exterior, or a variation based on the structure's contents and composition. The exemption requires written consent to inspect the interior and does not authorize changes to state building standards.
Compliance Timeline
Board adoption alone does not make Zone 0 operative. The regulations must first be approved and filed by OAL. In addition, Government Code section 51186(b)(2)(A) and Public Resources Code section 4291(g)(1) delay the Zone 0 requirements for new structures until the Board updates and posts its fuels-management guidance. The Board has up to one year after adopting the regulations to update that guidance.
The regulation text phases in duties for existing structures. Requirements already found in prior law - including clearing roofs and gutters, keeping firewood outside Zone 0, removing dead or dying branches and maintaining chimney clearance - apply when the regulations become effective. Other combustible-material, vegetation, fencing and outbuilding requirements are phased in over three to five years, depending on whether the property is in an LRA or SRA and whether an authorized implementation schedule is adopted.
Because the statutes also provide that Zone 0 requirements for existing structures take effect three years after the effective date for new structures, agencies should confirm the final OAL filing, updated guidance and any additional Board or State Fire Marshal direction before calculating enforceable deadlines.
Recommended Actions for Cities and Districts
- Track implementation. Monitor OAL action, publication of the updated fuels-management guidance and any related state direction before setting deadlines.
- Map covered facilities. Classify each owned, leased, operated or maintained site by its SRA or LRA status and confirm whether an LRA property is within a Very High Fire Hazard Severity Zone.
- Assess the first five feet. Document landscaping, mulch, fencing, outbuildings, stored materials, attached features, roofs, gutters and vulnerable openings at potentially covered facilities.
- Update programs and budgets. Review ordinances, inspection and penalty procedures, permit checklists, public notices, maintenance contracts, leases and capital improvement standards. Government Code section 51186 requires reasonable efforts to notify affected residents before penalties are imposed.
- Evaluate local alternatives. Where strict application creates a site-specific concern, begin developing the evidence, findings and ordinance needed for an authorized alternative rather than relying on informal exceptions.
Conclusion
The emergency regulations translate AB 3074's five-foot ember-resistant concept into detailed standards within California's existing defensible space system. Cities and districts should focus now on identifying potentially covered properties, monitoring the final effective dates and guidance, preparing consistent implementation procedures and deciding whether local alternatives are warranted.
For more information or questions, please contact Marco Martinez and/or Alex Gonzalez.
