ADU Rules in Dallas, Texas

Overview

Dallas, the third-largest city in Texas and county seat of Dallas County, is a major commercial and financial hub with a diverse mix of neighborhoods ranging from dense urban areas to large-lot suburban subdivisions. As a home rule city, Dallas fully governs ADU construction through its Development Code — there is no Texas statewide ADU preemption law.

Dallas operates under a unique dual development code structure: Chapter 51 (older zoning code) and Chapter 51A (newer comprehensive zoning ordinance). Which code applies depends on when a particular area was incorporated or rezoned. Many historic Dallas neighborhoods still fall under Chapter 51 districts.

Zoning Districts and ADU Allowances

In Dallas, ADUs (generally called "accessory dwelling units" or "secondary dwelling units" in the code) are permitted in most single-family residential districts:

• R-7.5(A), R-10(A), R-16(A) (Chapter 51A single-family): ADUs typically allowed as an accessory use
• Properties in planned development (PD) districts must check their specific PD conditions
• Duplex and multi-family zones have different rules for secondary units
• Corner lots may have different setback requirements than interior lots

Development Standards

Key ADU standards under the Dallas Development Code include:

• Maximum size: Typically limited to 1,500 sq ft, or a percentage of the primary dwelling floor area — confirm current limits for your district
• Height: Generally limited to one story or 25 ft for detached accessory structures
• Rear setback: 5 ft minimum from rear property line for detached ADUs
• Side setback: 5 ft minimum from side property line
• Front yard: ADUs must be located behind the primary dwelling's front building line
• Lot coverage: Total lot coverage (all structures) must not exceed the district maximum (typically 40–45%)
• Parking: One additional off-street parking space typically required

Neighborhood Conservation Overlays (NCOs)

Dallas has established numerous Neighborhood Conservation Overlays across the city. NCOs can significantly restrict what is otherwise permitted under base zoning, including:

• Minimum lot sizes that prevent subdivision
• Limits on the number of accessory structures per lot
• Restrictions on accessory dwelling units specifically
• Maximum impervious cover below the base district maximum
• Design and materials standards

Popular neighborhoods with NCOs include parts of Oak Cliff, East Dallas, Lake Highlands, Preston Hollow, and others. Always verify NCO status for your specific address through the Dallas Development Services portal before planning an ADU.

Trinity River Floodplain

The Trinity River corridor runs through Dallas, and significant portions of the city lie within FEMA-designated Special Flood Hazard Areas. The City of Dallas participates in the FEMA National Flood Insurance Program (NFIP) and the Community Rating System (CRS). Properties in flood hazard areas require a floodplain development permit, and structures must meet elevation requirements. White Rock Lake area and other low-lying neighborhoods should be carefully checked for flood zone status.

Historic Districts

Dallas has designated historic districts and landmark properties where new construction — including ADUs — requires approval from the Landmark Commission. The Oak Cliff, Swiss Avenue, and Wheatley Place historic districts are examples. Design review applies to materials, massing, and siting.

Permit Process

1. Look up your zoning district and overlay at dallascityhall.com/developmentservices
2. Confirm ADU allowance and applicable standards (Chapter 51 vs. 51A)
3. Check for NCOs, historic overlays, or floodplain restrictions
4. Submit building permit application with site plan and construction drawings to Development Services
5. Plan review for zoning compliance, building code, fire code
6. Inspections through certificate of occupancy

Contact

• Dallas Development Services: dallascityhall.com/developmentservices | 214-948-4480
• Dallas One Stop: One Stop building permit assistance, City Hall
• FEMA Flood Maps: msc.fema.gov

Disclaimer: Dallas ADU regulations vary significantly by zoning district and overlay. This page provides general guidance only. Always verify current rules with the City of Dallas Development Services Department and consult a licensed Texas professional before proceeding.