Zoning & Size Limits
| Requirement | Austin, TX | Houston, TX |
|---|
| Allowed Zones | SF3, SF2, SF1, MU, UR, etc. | SF, MF residential zones |
| Max Size (Detached) | 1,350 sq ft or 0.15 FAR (whichever is smaller; updated by HOME Phase 2, May 2024) | 1,200 sq ft |
| Max Size (Attached) | 1,350 sq ft or 0.15 FAR (whichever is smaller) | 800 sq ft |
| Max Height | 35 feet | 35 feet |
| Parking Required | 1 space for primary, optional for ADU | 1 off-street parking space required for ADU (separate from p |
| Owner Occupancy | Not required | Not required |
Setback Requirements
| Setback | Austin, TX | Houston, TX |
|---|
| Rear Setback | 10 feet | 15 feet |
| Side Setback | 3 feet (with easement) | 5 feet |
| Front Setback | 20 feet | 25 feet |
Permits & Timeline
| Detail | Austin, TX | Houston, TX |
|---|
| Permit Timeline | 45-60 days | 60-90 days |
| Permit Fees | $2,500-$4,000 | $3,000-$5,500 |
| Impact Fees | $1,200-$2,000 | $800-$1,500 |
| Pre-Approved Plans | City offers expedited review for pre-approved plan | Limited pre-approval program |
Construction Costs
| Cost | Austin, TX | Houston, TX |
|---|
| Avg Build Cost | $125,000-$250,000 | $120,000-$240,000 |
| Cost Per Sq Ft | $165-$330 | $100-$200 |
| Garage Conversion | $60,000-$140,000 | $50,000-$130,000 |
| Prefab ADU | $85,000-$200,000 | $80,000-$190,000 |
Rental Income Potential
| Rental | Austin, TX | Houston, TX |
|---|
| 1BR Avg Rent | $1,300-$1,900/mo | $1,100-$1,600/mo |
| 2BR Avg Rent | $1,700-$2,500/mo | $1,400-$2,100/mo |
| Short-Term Rentals | Check local restrictions | Varies by neighborhood |
| Est. ROI | 7-10% annual return | 6-9% annual return |
Which City Is Better for ADUs?
Austin scores 8/10 while Houston scores 6/10 on our ADU-friendliness index.
Austin 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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