Everything homeowners ask about building an ADU in Dallas — answered with 2026 data.
Yes, ADUs are allowed in Single-family residential — but ADUs are generally NOT by-right; most require an ADU Overlay (ADUO) or a deed-restriction/Board of Adjustment process (Dallas City Code §51A-4.510) in Dallas, TX. The maximum size for a detached ADU is 800 sq ft (Dallas caps ADUs at 800 sq ft). Attached ADUs can be up to Greater of 700 sq ft or 25% of the main dwelling's floor area (Dallas City Code §51A-4.510). Dallas has an ADU-friendliness score of 6/10. Check our full Dallas ADU rules page for complete zoning details.
ADU construction in Dallas typically costs $115,000-$230,000. The cost per square foot averages $130-$250. Garage conversions are more affordable at $55,000-$135,000, while prefab ADUs cost $80,000-$185,000. Permit fees add $2,200-$3,800 to your budget. See our detailed Dallas ADU cost guide.
Detached ADUs in Dallas can be up to 800 sq ft (Dallas caps ADUs at 800 sq ft). Attached ADUs are limited to Greater of 700 sq ft or 25% of the main dwelling's floor area (Dallas City Code §51A-4.510). Junior ADUs (JADUs) have a cap of 400 sq ft. Maximum height is 35 feet. You are allowed up to 1 ADU per lot on a qualifying lot.
Rear setback: 15 feet. Side setback: 5 feet. Front setback: 20 feet. Note that garage conversions may be exempt from setback requirements if the existing structure is already within the setback area.
Confirm with Dallas Planning & Development — an additional off-street space may be required depending on transit proximity and lot conditions. Many cities and states have been relaxing ADU parking requirements in recent years. In California, no additional parking is required for ADUs near transit.
Required — either the primary dwelling or the ADU must be owner-occupied; the non-owner-occupied unit must be registered under the city's Single Family Rental Registration Program. Note that owner-occupancy rules vary by state law — California and several other states have eliminated this requirement for standard ADUs.
The ADU permit review timeline in Dallas is typically 50-75 days. Plan check: 2-3 weeks. Pre-approved plans availability: Available for detached ADUs.
Average ADU rental income in Dallas: 1-bedroom units rent for $1,150-$1,700/month, 2-bedroom units for $1,450-$2,200/month. Short-term rentals: Not permitted in most areas. Expected ROI: 6-8% annual return.
The minimum lot size for an ADU in Dallas is No ADU-specific minimum - underlying zoning lot standards apply (Dallas Code 51A-4.510 sets none). This applies to detached ADUs — garage conversions and JADUs may have different or no lot size requirements.
Garage conversions are one of the most popular and affordable ADU options. In Dallas, a garage conversion typically costs $55,000-$135,000. The key advantages are lower cost (no foundation work), potential setback exemptions, and faster permitting. Read our complete garage conversion guide.