Dallas, TX Accessory Structures: ADU Rules (2026)

Dallas does not permit ADUs citywide by right. Sec. 510 defines an ADU as "a rentable additional dwelling unit, subordinate to the main unit, located on a building site with a single family use," but the unit is only lawful inside a City Council-approved ADU overlay district, created through the same petition process used for zoning amendments (Sec. 701). A neighborhood committee of at least 10 property owners must petition, a neighborhood meeting is held, and the overlay must cover at least 50 single-family structures in a compact area (or a whole subdivision if it has fewer than 50).

Once an overlay exists, the yard, lot and space rules in subsection (c) apply: a detached ADU behind a house shorter than 15 feet gets a 3-foot side and rear yard; a detached ADU has a 200-square-foot floor minimum and a 700-square-foot (or 25 percent of the main structure) maximum, and an attached ADU is capped the same way relative to the main use. Height cannot exceed the main dwelling unit except when the ADU sits above a detached garage, where the overlay's general height limit applies instead.

An ADU cannot be placed in front of the main structure absent a Board of Adjustment special exception, and it is capped at one story. Off-street parking defaults to one space per ADU but drops to zero within 1,200 feet of a DART bus or rail stop, and can be reduced further if 75 percent of overlay property owners petition for it. A lot with an ADU may carry no more than two electrical meters. The city plan commission and council review the overlay ordinance itself, and Sec. 510(c)(1)(D) makes the overlay's yard/lot/space rules control over the general single-family regulations in Sec. 209 wherever the two conflict.