A garage conversion is usually the lowest-cost path to an ADU in San Antonio — $50,000-$130,000, versus $110,000-$220,000 for a new detached build — because the shell already exists.
Garage Conversion Cost in San Antonio
Converting an existing garage in San Antonio runs $50,000-$130,000. That's well under the $110,000-$220,000 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 $4,000-$6,500. A converted unit rents for about $1,050-$1,550/mo (1BR) in San Antonio.
The San Antonio Garage Conversion Permit Process
A garage-to-ADU conversion in San Antonio needs building permits even if the exterior is unchanged. Approval process: Permitted by right in most residential zones (no conditional use permit needed); standard building permit — confirm zoning eligibility with San Antonio DSD The review timeline is 90-120 days, with plan check: 4-6 weeks. Pre-approved plans: Not available.
- Confirm eligibility — ADUs are allowed in Permitted by right (subject to use-specific standards) in most single-family/residential and rural districts under the UDC.
- Prepare conversion plans — layout, egress windows, insulation, ventilation, smoke/CO detectors, plus a kitchen and bathroom.
- Submit for plan check — 4-6 weeks.
- Pull permits and build — fees run $4,000-$6,500; then framing, electrical, plumbing, and final inspection.
Parking Rules for a Garage Conversion
One on-site space required only if the ADU exceeds 800 sq ft of gross floor area; no parking required for smaller units Garage conversions sometimes trigger different parking rules than new detached ADUs, so confirm replacement-parking requirements with San Antonio before you start. Note: Required — owner must occupy either the principal unit or the ADU as their permanent residence (residency affidavit required); the owner-occupied unit may not be rented.
Get Free ADU Quotes in San Antonio
Tell us about your project and we'll connect you with ADU builders serving San Antonio. Free, no obligation — you choose who to work with.
🔒 Your info is secure. We share it only with contractors quoting your project. No spam, no obligation.
San Antonio Garage Conversion FAQ
How much does a garage conversion cost in San Antonio?
Do I need a permit to convert a garage in San Antonio?
Do I have to replace the parking if I convert my garage in San Antonio?
How long does a garage conversion take in San Antonio?
Compare your options: see the full San Antonio ADU rules, estimate your build with the San Antonio ADU cost calculator, or read the general garage conversion guide.