Regulations for Accessory Dwelling Units in Dallas
Accessory dwelling units (ADUs) are primarily permitted in the City of Dallas through the establishment of an Accessory Dwelling Unit Overlay, which allows a single rentable second unit on a building site with a single-family use. Additionally, the City of Dallas allows for two-unit developments in the Residential Transition (RTN) district under the "Manor House" development type and provides a mechanism for the Dallas Board of Adjustment to grant special exceptions for non-rental second units in any district. Specific nonresidential districts also allow for "live units" or caretaker quarters as accessory residential uses.
The Accessory Dwelling Unit (ADU) Overlay
The Accessory Dwelling Unit Overlay is a specialized zoning tool used within the City of Dallas to allow property owners to create a rentable additional dwelling unit that is subordinate to the main unit on a single-family lot [Section 51A-4.510(a)].
Eligibility and Initiation
An ADU Overlay can only be placed in Dallas neighborhoods that currently allow single-family uses and do not expressly prohibit accessory units [Section 51A-4.510(b)(2)]. To initiate the process, a neighborhood committee must submit a petition to the City of Dallas representing a compact area containing at least 50 single-family structures [Section 51A-4.510(b)(3)].
Development Standards for ADUs
When an ADU is constructed under this overlay, it must comply with specific standards regarding size, height, and placement within the lot.
| Standard | Requirement |
|---|---|
| Minimum Floor Area | 200 square feet [Section 51A-4.510(c)(3)(C)] |
| Maximum Floor Area (Detached) | The greater of 700 square feet or 25% of the main structure [Section 51A-4.510(c)(3)(C)] |
| Maximum Floor Area (Attached) | The greater of 700 square feet or 25% of the main use [Section 51A-4.510(c)(3)(C)] |
| Minimum Side Setback | 3 feet (if unit is < 15 ft tall and in the rear 30% of the lot) [Section 51A-4.510(c)(2)(B)] |
| Minimum Rear Setback | 3 feet (if unit is < 15 ft tall and in the rear 30% of the lot) [Section 51A-4.510(c)(2)(B)] |
| Maximum Height | Cannot exceed the height of the main dwelling unit [Section 51A-4.510(c)(3)(D)] |
| Off-Street Parking | Minimum of 1 space required (waived if within 1,200 ft of a DART bus or rail station) [Section 51A-4.510(c)(2)(F)] |
Residential Transition (RTN) District Provisions
The Residential Transition (RTN) district is a specific category in the Dallas Development Code designed to serve as a buffer between intense walkable urban districts and established neighborhoods [Section 51A-13.301(c)].
In the RTN district, the City of Dallas permits the Manor House development type, which allows for two dwelling units to be consolidated into a single structure on a single lot [Section 51A-13.304(h)]. While a standard "Single-Family House" in the RTN district is limited to one unit, the Manor House provision effectively allows for a second unit by right without the need for an ADU Overlay [Section 51A-13.304(h)(1)].
Board of Adjustment Special Exceptions
The Dallas Board of Adjustment has the authority to grant a special exception to authorize an "additional dwelling unit" in any zoning district in the City of Dallas [Section 51A-4.209(b)(6)(E)].
However, units authorized via this special exception are subject to a critical restriction: the additional dwelling unit cannot be used as rental accommodations [Section 51A-4.209(b)(6)(E)(i)]. The Board of Adjustment requires the applicant to place a deed restriction on the property to enforce this non-rental status [Section 51A-4.209(b)(6)(E)(ii)].
Accessory Units in Nonresidential Districts
The Dallas Development Code identifies two other types of "second units" primarily found in nonresidential or mixed-use settings:
- Live Units: These are dwelling units accessory to a permitted nonresidential use. They are prohibited in most strictly residential and agricultural districts but are allowed in various commercial and industrial zones [Section 51A-4.217(8.1)].
- Caretaker's Quarters: Specifically permitted as an accessory use for Mini-warehouse facilities in districts such as Commercial Service (CS), Industrial, and Central Area districts. Dallas allows one parking space per 500 square feet of caretaker's quarters, with a maximum of two spaces per quarter [Section 51A-4.213(7)(E)].
Sections Cited
- Sec. 51A-4.111 through 4.127 (Zoning District Regulations)
- Sec. 51A-4.209 (Residential Uses)
- Sec. 51A-4.213 (Wholesale, Distribution, and Storage Uses)
- Sec. 51A-4.217 (Accessory Uses)
- Sec. 51A-4.510 (Accessory Dwelling Unit Overlay)
- Sec. 51A-13.301 (Districts Established)
- Sec. 51A-13.304 (Development Types)