Zoning & Size Limits
| Requirement | Houston, TX | San Antonio, TX |
|---|
| Allowed Zones | Houston has no zoning code — ADUs are governed by deed restr | Permitted by right (subject to use-specific standards) in mo |
| Max Size (Detached) | 900 sq ft (typical city standard; verify against deed restrictions and any 1,000 sq ft / 50%-of-primary limits) | 800 sq ft (1,200 sq ft in the RE zone) per UDC §35-371 |
| Max Size (Attached) | 900 sq ft | Up to 35% of the principal dwelling's living area (UDC §35-371) |
| Max Height | Confirm with City of Houston Planning — governed b | Generally may not exceed the height of the primary |
| Parking Required | 1 off-street parking space required for ADU (separate from p | One on-site space required only if the ADU exceeds 800 sq ft |
| Owner Occupancy | Not required by the city (no citywide owner-occupancy mandat | Required — owner must occupy either the principal unit or th |
Setback Requirements
| Setback | Houston, TX | San Antonio, TX |
|---|
| Rear Setback | 5 feet | 5 feet (detached ADU may be 3 ft or more from side and rear lines per UDC §35-371) |
| Side Setback | 5 feet | 5 feet |
| Front Setback | Confirm with City of Houston (front setback varies | 25 feet |
Permits & Timeline
| Detail | Houston, TX | San Antonio, TX |
|---|
| Permit Timeline | 60-90 days | 90-120 days |
| Permit Fees | $3,000-$5,500 | $4,000-$6,500 |
| Impact Fees | $800-$1,500 | $1,200-$2,200 |
| Pre-Approved Plans | Limited pre-approval program | Not available |
Construction Costs
| Cost | Houston, TX | San Antonio, TX |
|---|
| Avg Build Cost | $120,000-$240,000 | $110,000-$220,000 |
| Cost Per Sq Ft | $100-$200 | $140-$275 |
| Garage Conversion | $50,000-$130,000 | $50,000-$130,000 |
| Prefab ADU | $80,000-$190,000 | $75,000-$170,000 |
Rental Income Potential
| Rental | Houston, TX | San Antonio, TX |
|---|
| 1BR Avg Rent | $1,100-$1,600/mo | $1,050-$1,550/mo |
| 2BR Avg Rent | $1,400-$2,100/mo | $1,300-$1,950/mo |
| Short-Term Rentals | Varies by neighborhood | Not permitted |
| Est. ROI | 6-9% annual return | 5-7% annual return |
Which City Is Better for ADUs?
Houston scores 6/10 while San Antonio scores 5/10 on our ADU-friendliness index.
Houston edges ahead overall. Both cities offer viable ADU development opportunities — the best choice depends on your specific property, budget, and goals.
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