Zoning & Size Limits
| Requirement | San Antonio, TX | Fort Worth, TX |
|---|
| Allowed Zones | Permitted by right (subject to use-specific standards) in mo | One-family residential districts ('A-5', 'A-7.5', 'A-10', 'A |
| Max Size (Detached) | Lesser of 50% of primary structure or 1,000 sq ft (up to 1,200 sq ft for detached ADUs in some districts; up to 1,600 sq ft in certain SF districts other than FR per UDC §35-371) | 1,000 sq ft |
| Max Size (Attached) | Lesser of 50% of primary structure or 1,000 sq ft | Limited by the district's floor-area and lot-coverage rules |
| Max Height | Generally may not exceed the height of the primary | May not exceed the height of the primary residence |
| Parking Required | One on-site space required only if the ADU exceeds 800 sq ft | Off-street parking per district standards (confirm with Deve |
| Owner Occupancy | Required — owner must occupy either the principal unit or th | Effectively required — an ADU may not be a separate independ |
Setback Requirements
| Setback | San Antonio, TX | Fort Worth, TX |
|---|
| Rear Setback | 20 feet | Must meet the rear setback of the underlying district (commonly 5–10 ft for accessory structures) |
| Side Setback | 5 feet | Must meet the side setback of the underlying district (commonly 5 ft) |
| Front Setback | 25 feet | Must be behind the front building line of the prim |
Permits & Timeline
| Detail | San Antonio, TX | Fort Worth, TX |
|---|
| Permit Timeline | 90-120 days | About 4–9 weeks from complete application to permit issuance (confirm current queue with Development Services) |
| Permit Fees | $4,000-$6,500 | $2,400-$4,000 (building permit + plan review; varies with valuation and square footage) |
| Impact Fees | $1,200-$2,200 | $1,000-$1,800 typical water/sewer connection charges (confir |
| Pre-Approved Plans | Not available | No formal pre-approved ADU plan set; standard plan |
Construction Costs
| Cost | San Antonio, TX | Fort Worth, TX |
|---|
| Avg Build Cost | $110,000-$220,000 | $120,000-$240,000 |
| Cost Per Sq Ft | $140-$275 | $120-$240 |
| Garage Conversion | $50,000-$130,000 | $55,000-$135,000 |
| Prefab ADU | $75,000-$170,000 | $85,000-$195,000 |
Rental Income Potential
| Rental | San Antonio, TX | Fort Worth, TX |
|---|
| 1BR Avg Rent | $1,050-$1,550/mo | $1,100-$1,650/mo |
| 2BR Avg Rent | $1,300-$1,950/mo | $1,400-$2,100/mo |
| Short-Term Rentals | Not permitted | Restricted in most areas |
| Est. ROI | 5-7% annual return | 6-9% annual return |
Which City Is Better for ADUs?
San Antonio scores 5/10 while Fort Worth scores 5/10 on our ADU-friendliness index.
Both cities offer viable ADU development opportunities — the best choice depends on your specific property, budget, and goals.
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