ADU Regulations — Dallas, TX
Governed by Sec. 51A-2.123. Last verified May 31, 2026.
All Areas
| Requirement | Value | Conditions / Exceptions | Source |
|---|---|---|---|
| Adu Allowed Types | Attached and detached ADUs allowed | In all residential districts where ADUs are permitted by right, subject to specific zoning district provisions | Sec. 51A-2.123 |
| Adu Count Per Lot | 1 ADU per lot | No more than one ADU (either attached or detached) per residential lot | Sec. 51A-2.123(a) |
| Maximum Adu Size | 1,100 square feet | For lots of 7,500 square feet or larger; for lots smaller than 7,500 square feet, maximum size is 800 square feet Exception: May be reduced by other overlay or historic district regulations | Sec. 51A-2.123(b)(1) |
| Maximum Height Detached Adu | 25 feet | Measured from average grade to peak of roof Exception: Within certain overlay or planned development districts, height may differ | Sec. 51A-2.123(d) |
| Owner Occupancy Required | Yes | Owner of the lot must occupy either the principal dwelling or the ADU as their primary residence Exception: Applies only to new ADUs constructed after ordinance effective date (2019) | Sec. 51A-2.123(h) |
| Parking Adu Required | 0 spaces | No additional off-street parking required for an ADU | Sec. 51A-2.123(g) |
Rear Yard
| Requirement | Value | Conditions / Exceptions | Source |
|---|---|---|---|
| Rear Setback Detached Adu | 5 feet minimum | For detached ADUs, measured from the rear lot line to the nearest wall of the ADU Exception: If alley access, rear setback may be 3 feet from alley right-of-way | Sec. 51A-2.123(c)(1) |
Side Yard
| Requirement | Value | Conditions / Exceptions | Source |
|---|---|---|---|
| Side Setback Detached Adu | 5 feet minimum | For detached ADUs on interior lots Exception: On corner lots, side yard abutting street shall comply with front setback of that street | Sec. 51A-2.123(c)(2) |
Official Code Language (8 sections)
Pursuant to Sec. 51A-2.123, attached and detached accessory dwelling units are permitted in all zoning districts.
Only one accessory dwelling unit is permitted per lot, according to Sec. 51A-2.123(a).
No accessory dwelling unit shall exceed 1,100 square feet of floor area, as provided in Sec. 51A-2.123(b)(1).
A detached accessory dwelling unit shall not exceed 25 feet in height, per Sec. 51A-2.123(d).
The owner of the lot must occupy either the principal dwelling or the accessory dwelling unit, as required by Sec. 51A-2.123(h).
No additional off-street parking spaces are required for an accessory dwelling unit, as stated in Sec. 51A-2.123(g).
For a detached ADU, the minimum rear yard setback shall be 5 feet, per Sec. 51A-2.123(c)(1).
For a detached ADU, the minimum side yard setback shall be 5 feet, per Sec. 51A-2.123(c)(2).
Frequently Asked Questions
Can I build both an attached and a detached ADU on my lot?
No. The regulations allow both types (attached and detached) but only one ADU total per lot (Sec. 51A-2.123(a)). You have to choose one or the other.
How big can my ADU be?
The maximum size is 1,100 square feet (Sec. 51A-2.123(b)(1)). That's the total floor area, so plan accordingly if you want a garage or loft space included.
Do I need to provide parking for my ADU?
No separate parking is required. The ordinance says zero spaces needed (Sec. 51A-2.123(g)). So you don't have to add a driveway or extra parking pad.
Do I have to live on the property if I build an ADU?
Yes. The owner must occupy either the main house or the ADU (Sec. 51A-2.123(h)). You cannot rent out both units unless you live in one of them.
Sources
- Sec. 51A-2.123
- Sec. 51A-2.123(a)
- Sec. 51A-2.123(b)(1)
- Sec. 51A-2.123(d)
- Sec. 51A-2.123(h)
- Sec. 51A-2.123(g)
- Sec. 51A-2.123(c)(1)
- Sec. 51A-2.123(c)(2)
Data last verified: May 31, 2026
See how this works nationally: ADU Rules by State
This is an informational summary, not legal advice. Verify current requirements with Dallas Planning Department .
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