Zoning & Size Limits
| Requirement | Phoenix, AZ | Tucson, AZ |
|---|
| Allowed Zones | Single-family residential zones | Limited to select residential zones |
| Max Size (Detached) | 900 sq ft | 75% of primary dwelling, up to 1,000 sq ft (minimum 650 sq ft guaranteed) |
| Max Size (Attached) | 75% of primary dwelling, capped at 1,000 sq ft (lots ≤10,000 sq ft) | 75% of primary dwelling, up to 1,000 sq ft (minimum 650 sq ft guaranteed) |
| Max Height | 15 ft (use permit may allow more) | 30 feet |
| Parking Required | No additional parking required (AZ HB 2720, effective Jan 20 | No parking required (effective November 2024, AZ HB 2720) |
| Owner Occupancy | Not required | May be required in some zones |
Setback Requirements
| Setback | Phoenix, AZ | Tucson, AZ |
|---|
| Rear Setback | 15 feet | 20 feet |
| Side Setback | 5 feet | 5 feet |
| Front Setback | 25 feet | 25 feet |
Permits & Timeline
| Detail | Phoenix, AZ | Tucson, AZ |
|---|
| Permit Timeline | 60-90 days | 90-120 days |
| Permit Fees | $2,500-$4,200 | $3,500-$5,500 |
| Impact Fees | $900-$1,600 | $1,200-$2,000 |
| Pre-Approved Plans | Limited availability | Not available |
Construction Costs
| Cost | Phoenix, AZ | Tucson, AZ |
|---|
| Avg Build Cost | $120,000-$240,000 | $110,000-$220,000 |
| Cost Per Sq Ft | $135-$270 | $145-$290 |
| Garage Conversion | $60,000-$140,000 | $55,000-$130,000 |
| Prefab ADU | $85,000-$200,000 | $80,000-$180,000 |
Rental Income Potential
| Rental | Phoenix, AZ | Tucson, AZ |
|---|
| 1BR Avg Rent | $1,250-$1,700/mo | $1,100-$1,500/mo |
| 2BR Avg Rent | $1,600-$2,200/mo | $1,400-$1,900/mo |
| Short-Term Rentals | Varies by neighborhood | Not permitted |
| Est. ROI | 7-10% annual return | 6-8% annual return |
Which City Is Better for ADUs?
Phoenix scores 6/10 while Tucson scores 5/10 on our ADU-friendliness index.
Phoenix 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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