The Orange County Fire Authority’s C-05 guideline, dated January 1, 2026, describes a fuel-modification plan review for new ADUs in its wildfire-risk scope. The trigger depends on mapped or officially designated conditions and on where the project sits in the permit sequence. It is an OCFA-area checkpoint, not a statewide ADU requirement or a conclusion about a particular parcel.
Check the authority and mapped area
The guideline says new ADUs and other listed structures built in, or adjacent to, a wildfire-risk area or an area designated by the fire code official require a Fuel Modification Plan in conjunction with the 2025 California Wildland Urban Interface Code. It identifies State Responsibility Areas and Local Responsibility Areas classified as High or Very High Fire Hazard Severity Zones.
Maps and designations can change, and the guideline says wildfire requirements may be updated. Confirm whether OCFA is the responsible fire authority for the property, whether the current map or fire official designates the site, and what state wildfire rules apply at the time the plans are submitted. The guideline lists an OCFA technical line for project-specific confirmation.
Identify the plan stage
The C-05 guide describes two stages. A conceptual plan generally comes before tentative tract-map, parcel-map, or fire-master-plan approval and shows the proposed zone layout and intent. A precise plan includes the planting plan, final specifications, and inspection information and is due before grading-permit or building-permit issuance, whichever comes first, and before fire-master-plan approval. The guide allows the conceptual and precise materials to be combined when the detailed information is ready.
The guideline also lists vegetation-clearance and final inspections in its process, including a final plan inspection before occupancy. Ask the reviewing authority which submittal and inspection checkpoints apply to the proposed project; do not rely on a general ADU checklist to replace fire-authority review.
Read the current C-05 Fuel Modification Plans Design guideline together with current state and local requirements. This overview identifies the trigger and sequence only; it does not design a fuel-modification plan.