ADU (Accessory Dwelling Unit) permit in McKinney, TX
Yes — you need a permit for adu (accessory dwelling unit) work in McKinney.
| 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 | Sec. 122-25 (adoption of IBC/IRC 2021); IRC R105.2 (new dwelling unit not exempt) |
| Based on | IBC/IRC 2021 as adopted (McKinney Sec. 122-25) |
How to pull the permit
- Put together a site plan showing where the work goes, with dimensions.
- Apply through the McKinney 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
McKinney'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 |
|---|---|---|---|
| McKinney | — | Yes | No size threshold in the code |
| Allen | 6 mi | Yes | No size threshold in the code |
| Plano | 11 mi | Yes | Building a garage apartment, casita, or other accessory d… |
| Richardson | 16 mi | Yes | No size threshold in the code |
| Lewisville | 21 mi | Yes | No size threshold in the code |
| Denton | 28 mi | Yes | No size threshold in the code |
Other work in McKinney
Questions people ask
I already built it without a permit. What now?
McKinney 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.