ADU (Accessory Dwelling Unit) permit in Austin, TX
Yes — you need a permit for adu (accessory dwelling unit) work in Austin.
| Permit needed? | Yes |
|---|---|
| Where the line falls | No size threshold in the code |
| Fee | Not in the ordinance — the department quotes it |
| Review time | Not in the ordinance |
| Code section | R105.2 (as amended) - accessory structure exemption excludes structures that create a dwelling |
| Based on | 2024 IRC as amended by City of Austin (§ 25-12-241, § 25-12-243) |
How to pull the permit
- Put together a site plan showing where the work goes, with dimensions.
- Apply through the Austin 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
Austin'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 |
|---|---|---|---|
| Austin | — | Yes | No size threshold in the code |
| Round Rock | 17 mi | Yes | No size threshold in the code |
| New Braunfels | 47 mi | Yes | No size threshold in the code |
| Killeen | 54 mi | Yes | You need a building permit to build an accessory dwelling… |
| San Antonio | 74 mi | Yes | Building an accessory dwelling unit (garage apartment, ca… |
| College Station | 89 mi | Yes | No size threshold in the code |
Other work in Austin
Questions people ask
I already built it without a permit. What now?
Austin 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.