Zoning & Size Limits
| Requirement | Mesa, AZ | Tempe, AZ |
|---|
| Allowed Zones | All districts where a single residence is allowed (Agricultu | All single-family residential districts citywide (per ARS 9- |
| Max Size (Detached) | 75% of primary residence's interior habitable area or 1,000 sq ft, whichever is less | 1,000 sq ft or 75% of the main dwelling's gross floor area, whichever is less |
| Max Size (Attached) | 75% of primary residence's interior habitable area or 1,000 sq ft, whichever is less | 1,000 sq ft or 75% of the main dwelling's gross floor area, whichever is less |
| Max Height | Same as primary residence height limit for the und | Same as the underlying zoning district standard (t |
| Parking Required | No additional parking required; garage/carport conversions n | No additional parking may be required (ARS 9-461.18 bars ADU |
| Owner Occupancy | Not required | Not required for long-term rentals; owner must reside on sit |
Setback Requirements
| Setback | Mesa, AZ | Tempe, AZ |
|---|
| Rear Setback | 5 feet minimum for new structures; existing-structure conversions require no additional setback | 5 feet minimum (all districts, unless the district allows less) |
| Side Setback | 5 feet minimum for new structures | 5 feet minimum, including street side yards (all districts, unless the district allows less) |
| Front Setback | Same as primary residence front and street-side se | Per underlying zoning district — Confirm with Temp |
Permits & Timeline
| Detail | Mesa, AZ | Tempe, AZ |
|---|
| Permit Timeline | Residential plan review commonly runs days-to-weeks per third-party permit data (3-18 business days cited); confirm current turnaround on Mesa's Building Permits Dashboard | Typically 4-8 weeks for residential plan review — Confirm with Tempe Community Development |
| Permit Fees | Valuation-based per Mesa's Schedule of Fees & Charges; no flat ADU fee published — confirm with Mesa Development Services | Building permit and plan review fees based on valuation — Confirm with Tempe Community Development |
| Impact Fees | Development impact fees apply per Mesa City Code Title 5, Ch | Confirm with Tempe Community Development; state law bars ADU |
| Pre-Approved Plans | No city pre-approved ADU plan program identified a | No city pre-approved plan library — Confirm with T |
Construction Costs
| Cost | Mesa, AZ | Tempe, AZ |
|---|
| Avg Build Cost | $120,000-$240,000 | $120,000-$250,000 |
| Cost Per Sq Ft | $135-$270 | $140-$280 |
| Garage Conversion | $60,000-$140,000 | $60,000-$140,000 |
| Prefab ADU | $85,000-$200,000 | $85,000-$200,000 |
Rental Income Potential
| Rental | Mesa, AZ | Tempe, AZ |
|---|
| 1BR Avg Rent | $1,150-$1,450/mo | $1,300-$1,700/mo |
| 2BR Avg Rent | $1,400-$1,800/mo | $1,600-$2,100/mo |
| Short-Term Rentals | Ordinance 5883 does not address short-term rental of ADUs; A | Allowed with an Arizona/Tempe STR license, but the owner mus |
| Est. ROI | 6-9% annual return | 7-10% annual return |
Which City Is Better for ADUs?
Mesa scores 7/10 while Tempe scores 7/10 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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