ADU (Accessory Dwelling Unit) permit in Tempe, AZ
Yes — you need a permit for adu (accessory dwelling unit) work in Tempe.
Building an accessory dwelling unit (garage apartment, casita, or similar) needs both a building permit and zoning approval. An ADU is a new, independent habitable dwelling unit with its own living, sleeping, cooking, and sanitation facilities, so it is not covered by the small accessory-structure exemption (which is limited to one-story sheds 200 square feet or less with no mechanical, electrical, or plumbing). ADUs are a regulated use under Zoning and Development Code Section 3-402 and must meet its standards.
| Permit needed? | Yes |
|---|---|
| Where the line falls | Building an accessory dwelling unit (garage apartment, ca… |
| Fee | Not in the ordinance — the department quotes it |
| Review time | Not in the ordinance |
| Code section | ZDC Section 3-402 (Accessory Dwelling Units); IRC 101.4.2 / 105.2 |
| Based on | 2024 IRC as adopted and amended by City of Tempe (Sec. 8-105) and City of Tempe Zoning and Development Code, Section 3-402 |
How to pull the permit
- Put together a site plan showing where the work goes, with dimensions.
- Apply through the Tempe building department.
- Pay the permit fee when the permit is issued. Work done before that isn't covered.
- Book each inspection listed on the permit as the job reaches that stage.
Either of you can pull it. When a contractor does the work, it is normally their job.
If you skip it
Tempe's code doesn't set a specific fine for this work. In practice the department can issue a stop-work order, and unpermitted work tends to surface during a sale, when the buyer's inspector or the title company asks for it.
Nearby cities, same job
Rules stop at the city line. If your lot is near a boundary, or you work across several towns, this is where they differ.
| City | Distance | Permit? | Where the line falls |
|---|---|---|---|
| Tempe | — | Yes | Building an accessory dwelling unit (garage apartment, ca… |
| Chandler | 9 mi | Yes | Building an accessory dwelling unit (a casita, garage apa… |
| Gilbert | 12 mi | Yes | Plan on a building permit (plus electrical, plumbing, and… |
| Mesa | 12 mi | Yes | Building an accessory dwelling unit (a casita, garage apa… |
| Glendale | 18 mi | Yes | Building an accessory dwelling unit (garage apartment, ca… |
| Scottsdale | 21 mi | Yes | Plan on a building permit plus zoning approval to build a… |
See every Arizona city on adu (accessory dwelling unit) work
Other work in Tempe
- Fence Depends
- Deck Depends
- Shed Depends
- Swimming Pool Yes
- Roof Replacement Depends
- Water Heater Depends
- HVAC Replacement Depends
- Electrical Panel Yes
- Demolition Yes
- Driveway —
- Tree Removal —
- Sign Yes
- Short-Term Rental Yes
- ADU (Accessory Dwelling Unit) Yes
- Garage Yes
- Basement Yes
- Above-Ground Pool Depends
Questions people ask
I already built it without a permit. What now?
Tempe can issue a stop-work order and require you to apply after the fact, sometimes with an extra fee. Work that was covered up may have to be opened for inspection. Full walkthrough here.
Does unpermitted work cause problems when selling the house?
Often, yes. A buyer's inspector or the title company may flag it, and lenders can balk at financing a home with open or missing permits. What to do about it.