San Antonio has limited ADU allowances, primarily in certain zoning districts. The city is less progressive on ADU regulations than Austin or Dallas, requiring careful site analysis to verify compatibility with local zoning.
Zoning & Size Requirements [1][2]
Yes, you can build an ADU in San Antonio. A detached ADU can be up to 1,200 sq ft under current Texas and San Antonio zoning rules.
| Allowed Zones | Permitted by right (subject to use-specific standards) in most single-family/residential and rural districts under the UDC |
| Max Size (Detached) | 800 sq ft (1,200 sq ft in the RE zone) per UDC §35-371 |
| Max Size (Attached) | Up to 35% of the principal dwelling's living area (UDC §35-371) |
| Max Size (JADU) | Not allowed |
| Max Height | Generally may not exceed the height of the primary residence (commonly 25-30 ft); varies by zoning district |
| Max Units | 1 ADU per lot |
Setback Requirements [1][2]
San Antonio requires a rear setback of about 5 ft for a detached ADU, and parking requirements vary by unit size or location. Owner-occupancy is required.
| Rear Setback | 5 feet (detached ADU may be 3 ft or more from side and rear lines per UDC §35-371) |
| Side Setback | 5 feet |
| Front Setback | 25 feet |
| Parking Required | One on-site space required only if the ADU exceeds 800 sq ft of gross floor area; no parking required for smaller units |
| Owner Occupancy | 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 |
| Min Lot Size | 7,500 sq ft |
Permit Process & Fees
An ADU permit in San Antonio typically costs $4,000-$6,500 and takes 90-120 days, through a standard permit review.
| Approval Process | Permitted by right in most residential zones (no conditional use permit needed); standard building permit — confirm zoning eligibility with San Antonio DSD |
| Review Timeline | 90-120 days |
| Permit Fees | $4,000-$6,500 |
| Impact Fees | $1,200-$2,200 |
| Plan Check | 4-6 weeks |
| Pre-Approved Plans | Not available |
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Construction Costs [3][4]
Building an ADU in San Antonio typically costs $110,000-$220,000 ($140-$275 per sq ft); a garage conversion runs $50,000-$130,000.
| Average Build Cost | $110,000-$220,000 |
| Cost per Sq Ft | $140-$275 |
| Garage Conversion | $50,000-$130,000 |
| Prefab ADU (Installed) | $75,000-$170,000 |
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Rental Income Potential [5][6]
A 2-bedroom ADU in San Antonio rents for around $1,300-$1,950/mo, an estimated 5-7% annual return.
| Avg Rent (1 Bedroom) | $1,050-$1,550/mo |
| Avg Rent (2 Bedroom) | $1,300-$1,950/mo |
| Short-Term Rental | Not permitted |
| Est. Annual ROI | 5-7% annual return |
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Recent Law Changes
What's Changed Recently
- Data accuracy correction (2026-06-28): updated per official city/state sources following a regulatory audit.
- Texas SB 673 (statewide ADU preemption) died when the 89th Legislature adjourned without final passage — June 2025. No statewide ADU law
- Under the UDC (§35-371), ADUs are permitted by right in most residential districts subject to use-specific standards
- ADU max size: lesser of 50% of primary or 1,000 sq ft (up to 1,200 sq ft detached in some districts); owner-occupancy of one unit is required and the owner-occupied unit may not be rented
- Parking required (1 space) only for ADUs over 800 sq ft
Tips for Building an ADU in San Antonio
- San Antonio requires conditional use permits; factor 90+ day timeline into plans
- Verify your specific zoning district; many zones don't allow ADUs
- Neighborhood compatibility considerations are heavily weighted in approval
- Strong rental market in central areas; location matters significantly for ROI
ADU Builders in San Antonio
Looking for an ADU builder in San Antonio? ADU projects need a contractor experienced with local zoning, the permit process, and utility connections — not every general contractor has built one. We match San Antonio homeowners with experienced local ADU contractors who provide free, no-obligation quotes. Getting at least three bids typically saves 20-40% on the same scope.
Sources & References
All data on this page is sourced from official government records and verified market data. View our full methodology.
- Accessory Dwelling Unit (ADU) Permits — City of San Antonio Planning Department — Accessed 2026-06-28
- San Antonio UDC § 35-371 — Accessory Dwelling Units (Municode) Municipal Code — Accessed 2026-06-28
- Angi — ADU Construction Cost Data Market Data — Accessed 2026-02-24
- Angi — Local ADU Contractor Costs Market Data — Accessed 2026-02-24
- Zillow Rental Manager — Market Rent Data Market Data — Accessed 2026-02-24
- HUD Fair Market Rents Government Data — Accessed 2026-02-24
- San Antonio UDC § 35-371 — Accessory Dwellings Municipal Code — Accessed 2026-02-24
- Texas Local Government Code — Land Use Regulations Government Data — Accessed 2026-02-24
Frequently Asked Questions
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