A garage conversion is usually the lowest-cost path to an ADU in Huntington Beach — $90,000-$150,000, versus $180,000-$420,000 for a new detached build — because the shell already exists.
Garage Conversion Cost in Huntington Beach
Converting an existing garage in Huntington Beach runs $90,000-$150,000. That's well under the $180,000-$420,000 typical cost of a ground-up detached ADU, because you're reusing the foundation, walls, and roof. The biggest variables are whether the slab and framing are sound, what utility/electrical upgrades are needed, and your finish level. Permit fees add Building permits roughly $2,000-$10,000 plus other city fees of $3,000-$11,000 depending on project size (secondary-source estimates); a 6% automation fee is added — confirm with the HB Permit Center fee schedule. A converted unit rents for about $2,400-$2,700/mo (1BR) in Huntington Beach.
The Huntington Beach Garage Conversion Permit Process
A garage-to-ADU conversion in Huntington Beach needs building permits even if the exterior is unchanged. Approval process: Ministerial building permit through the Permit Center (714-536-5271, permitcenter@surfcity-hb.org); no discretionary entitlement, but Coastal Zone properties may need a Coastal Development Permit — verify your parcel's coastal status with Planning first The review timeline is Initial plan review approximately 20 days, resubmittals 5-10 days; state law caps total ADU review at 60 days with deemed approval (SB 543, 2026), with plan check: Plan check via Permit Center; ~20-day first review, 5-10 days for rechecks — confirm current turnaround with the city. Pre-approved plans: Yes — free pre-approved 1-story, 490 sq ft detached ADU prototype in three styles (California Ranch, Bungalow, Spanish Colonial) under AB 1332; modifications to the pre-approved plan are not allowed.
- Confirm eligibility — ADUs are allowed in All single-family and multifamily residential zones per state ADU law; local HBZSO Section 230.10 is no longer in effect per the city. Coastal Zone parcels may require a Coastal Development Permit.
- Prepare conversion plans — layout, egress windows, insulation, ventilation, smoke/CO detectors, plus a kitchen and bathroom.
- Submit for plan check — Plan check via Permit Center; ~20-day first review, 5-10 days for rechecks — confirm current turnaround with the city.
- Pull permits and build — fees run Building permits roughly $2,000-$10,000 plus other city fees of $3,000-$11,000 depending on project size (secondary-source estimates); a 6% automation fee is added — confirm with the HB Permit Center fee schedule; then framing, electrical, plumbing, and final inspection.
No Replacement Parking Required
No. California law (AB 68 / Gov Code §66314) prohibits cities from requiring replacement parking when you convert or demolish a garage to build an ADU — so you do not need to add a parking space anywhere on the lot. Owner-occupancy is not required, so you can rent the converted unit out.
The JADU Option for an Attached Garage
If your garage is attached to the house, you can convert it into a junior ADU (JADU) — capped at 500 sq ft (within existing home or attached garage) and built within the existing walls. JADUs are cheaper and faster to permit than a full ADU, though they may share sanitation with the main home. A full ADU gives you more size and a separate unit; a JADU is the budget route.
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Huntington Beach Garage Conversion FAQ
How much does a garage conversion cost in Huntington Beach?
Do I need a permit to convert a garage in Huntington Beach?
Do I have to replace the parking if I convert my garage in Huntington Beach?
How long does a garage conversion take in Huntington Beach?
Can I convert an attached garage into a JADU in Huntington Beach?
Compare your options: see the full Huntington Beach ADU rules, estimate your build with the Huntington Beach ADU cost calculator, or read the general garage conversion guide.