Nearly 13,000 homes burned across Los Angeles County in the January 2025 fires. More than a year later, permits have been issued for roughly one in five of the affected lots, and only about 30 percent of those permitted projects have started construction. Permit review for a new single-family home in unincorporated LA County averages 118 days, and that figure does not include plan revisions, contractor scheduling, or insurance delays.
Under these conditions, a homeowner who lost a house faces an 18 to 36 month wait for a traditional stick-built rebuild on the same lot.
A faster route exists, and most displaced families have never heard of it. The approach places a manufactured ADU on the lot as the first permanent structure, makes that unit legal to live in before the main house is finished, and can reach move-in within roughly 90 days of signing a contract. Two state laws from 2025 make it possible.
What AB 462 Changed
California law used to block this entirely. An ADU could not receive its Certificate of Occupancy until the primary home on the lot had one, because the ADU was legally an accessory to a main dwelling. A family with a burned house could install a finished, fully inspected unit and still be forbidden to sleep in it.
AB 462 ended that restriction in October 2025 for properties in counties under a Governor-declared emergency dated on or after February 1, 2025. Both LA County and Ventura County are covered, which includes Altadena, Pacific Palisades, Malibu, and Sierra Madre.
The mechanics are simple. Where the primary home was substantially damaged or destroyed in the declared emergency, the local agency must grant a Certificate of Occupancy to a permitted detached ADU on that lot as soon as it passes final inspection. The family moves in while the main rebuild continues.
Why Manufactured Construction Fits This Pathway
Stick-built construction cannot realistically hit a 90 day target. Each stage waits on the one before it. Permits come first, then foundation, framing, rough-in inspections, drywall, and finish work, with a separate inspection cycle at nearly every step. In a county processing thousands of rebuild applications at once, those waits stack up.
Factory construction breaks the sequence. The home is assembled in a plant while crews prepare the lot at the same time, and the factory side is inspected by the California Department of Housing and Community Development instead of the local building department, so the unit arrives already certified.
Two more laws shrink the local side of the process. AB 818 gives agencies 10 business days to decide on an HCD-approved unit. AB 1332 obligates every city and county in the state to keep a library of pre-approved ADU plans, and choosing one of those plans skips design review completely.
All four pieces together produce the 90 day result. Factory certification, the AB 818 clock, a pre-approved plan, and AB 462 occupancy. Take away any one of them and the schedule stretches.
The 90 Day Schedule
The timeline below assumes a lot in unincorporated LA County that has already finished Army Corps of Engineers Phase 2 debris removal. By early 2026, over 99 percent of Altadena lots had reached that point.
| Phase | Days | What Happens |
|---|---|---|
| Site assessment | 1 to 7 | Lot survey, soil report review, plan chosen from the pre-approved library |
| Permitting | 7 to 21 | Application filed, the 10 day clock under AB 818 runs, approval comes back |
| Site work and factory build | 21 to 75 | Foundation, utility trenching, and pad prep on the lot while the factory builds the home in parallel |
| Delivery and install | 75 to 82 | Unit transported, crane-set onto the foundation, anchored, and sealed |
| Final hookups and inspection | 82 to 90 | Electrical, plumbing, and gas connections, final inspection, AB 462 Certificate of Occupancy issued |
A few things can stretch this. Poor soil adds foundation time. Coordinating hookups with LA County DWP, Edison, or SoCalGas can cost a week. Modifying a pre-approved plan adds three to four weeks of plan check. With everything in order, 90 days holds up as a realistic number.
The Stick-Built Alternative
Compare that with rebuilding the original home the conventional way under current conditions.
| Phase | Realistic Duration |
|---|---|
| Design and architecture | 3 to 6 months |
| County permit review | 3 to 5 months |
| Foundation | 1 to 2 months |
| Framing through rough-in inspections | 4 to 6 months |
| Finish work and final inspections | 3 to 5 months |
| Total | 14 to 24 months minimum |
Even that range assumes an available licensed contractor, financing already arranged, and no insurance fight. Research from the UCLA Latino Policy and Politics Institute published in March 2026 found that just 30 percent of fire-affected properties with approved permits had broken ground, with the constraint having moved from permitting to contractor capacity and construction money.
Who Qualifies Under AB 462
Eligibility comes down to three tests.
The lot must sit in a qualifying disaster county, and both LA County and Ventura County qualify under the February 2025 proclamation.
The main home must have been substantially damaged or destroyed in that emergency. Total losses qualify without question. Partial damage and smoke damage are judged case by case by the local jurisdiction.
The ADU itself still needs a building permit and a passed final inspection. Nothing in AB 462 waives code or permitting standards.
Meet all three and the Certificate of Occupancy stops being a discretionary decision. State law requires the agency to issue it.
What It Costs
A manufactured ADU between 600 and 1,200 square feet generally comes in between 200,000 and 400,000 dollars complete in LA County. That number covers the unit, delivery, foundation, installation, utility connections, and standard finishes.
Fire-affected owners have several ways to offset the cost. LA County waived certain permit fees for rebuild projects through the unified permitting authority it created in 2025. The CalHFA ADU Grant Program provides up to 40,000 dollars for pre-development expenses like site preparation, permits, soil testing, and impact fees. Insurance money can often go toward the unit when it serves as replacement housing during the rebuild, though carriers differ and written confirmation is essential. FEMA Individual Assistance and SBA disaster loans round out the options for qualifying households.
Rebuilding the original home conventionally in these areas typically costs 500,000 dollars to well over 1.5 million depending on size and finish, across that 14 to 24 month window. The ADU route cuts down the months a family spends paying for housing elsewhere, and the lot keeps a permanent second dwelling after the main house is done.
Questions Families Ask
Will the ADU affect the insurance settlement?
Policy language decides. Most carriers treat the unit separately from the dwelling coverage on the destroyed home, and some will apply Additional Living Expense coverage toward the build because the unit serves as temporary housing. Get the answer from the adjuster in writing before signing anything.
Can the unit be rented once the main house is done?
Yes. After the primary home is rebuilt and occupied, the unit functions as an ordinary accessory dwelling under state rental rules. In Altadena and Pacific Palisades, units of 800 to 1,000 square feet typically rent for 3,000 to 4,500 dollars per month.
What about a custom design?
Custom is available, at the price of time. Skipping the pre-approved library adds three to six weeks of plan check up front and usually pushes the full schedule to 120 to 150 days.
Does any of this help owners outside the fire zones?
The early occupancy rule in AB 462 applies only to declared disaster properties. Everything else, meaning the manufactured unit itself, the AB 818 permit deadline, and the pre-approved plan libraries, is available statewide.
Getting Started
Three checks tell you whether a specific lot fits the 90 day path. Verify clearance status with LA County Public Works, because Phase 2 debris removal has to be finished before a permit can issue. Order a current soil report, since many burned lots need fresh geotechnical work before a foundation can be designed. Then price the project against the actual lot, because unit size, utility run distances, and foundation type set the real number.
BuiltADU advises owners of fire-affected properties in Altadena, Pacific Palisades, and throughout LA County, in English and in Spanish.
A final note on timing. AB 462 lives and dies with the February 2025 state of emergency. Once the declaration is lifted, the old rule returns and an ADU again cannot be occupied ahead of the main home. Families who start while the emergency is active keep the full protection of the law.
