A garage conversion is usually the lowest-cost path to an ADU in San Francisco — $120,000-$250,000, versus $200,000-$450,000 for a new detached build — because the shell already exists.
Garage Conversion Cost in San Francisco
Converting an existing garage in San Francisco runs $120,000-$250,000. That's well under the $200,000-$450,000 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 $5,000-$20,000 depending on scope. A converted unit rents for about $2,200-$3,200/mo (1BR) in San Francisco.
The San Francisco Garage Conversion Permit Process
A garage-to-ADU conversion in San Francisco needs building permits even if the exterior is unchanged. Approval process: Ministerial (no discretionary review or public hearing) The review timeline is 60-day review period (state-mandated), with plan check: Expedited plan check available. Pre-approved plans: Yes — SF has pre-approved ADU plan sets.
- Confirm eligibility — ADUs are allowed in RH-1, RH-2, RH-3, RM, RTO zones and most residential districts.
- Prepare conversion plans — layout, egress windows, insulation, ventilation, smoke/CO detectors, plus a kitchen and bathroom.
- Submit for plan check — Expedited plan check available.
- Pull permits and build — fees run $5,000-$20,000 depending on scope; 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 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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San Francisco Garage Conversion FAQ
How much does a garage conversion cost in San Francisco?
Do I need a permit to convert a garage in San Francisco?
Do I have to replace the parking if I convert my garage in San Francisco?
How long does a garage conversion take in San Francisco?
Can I convert an attached garage into a JADU in San Francisco?
Compare your options: see the full San Francisco ADU rules, estimate your build with the San Francisco ADU cost calculator, or read the general garage conversion guide.