Everything homeowners ask about building an ADU in San Antonio — answered with 2026 data.
Yes, ADUs are allowed in Selected residential zones only in San Antonio, TX. The maximum size for a detached ADU is 800 sq ft. Attached ADUs can be up to Not typically allowed. San Antonio has an ADU-friendliness score of 5/10. Check our full San Antonio ADU rules page for complete zoning details.
ADU construction in San Antonio typically costs $110,000-$220,000. The cost per square foot averages $140-$275. Garage conversions are more affordable at $50,000-$130,000, while prefab ADUs cost $75,000-$170,000. Permit fees add $4,000-$6,500 to your budget. See our detailed San Antonio ADU cost guide.
Detached ADUs in San Antonio can be up to 800 sq ft. Attached ADUs are limited to Not typically allowed. Junior ADUs (JADUs) have a cap of Not allowed. Maximum height is 30 feet. You are allowed up to 1 ADU per lot on a qualifying lot.
Rear setback: 20 feet. Side setback: 5 feet. Front setback: 25 feet. Note that garage conversions may be exempt from setback requirements if the existing structure is already within the setback area.
2 spaces. Many cities and states have been relaxing ADU parking requirements in recent years. In California, no additional parking is required for ADUs near transit.
Not required. 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 San Antonio is typically 90-120 days. The plan check process takes approximately 4-6 weeks. Pre-approved plans availability: Not available.
Average ADU rental income in San Antonio: 1-bedroom units rent for $1,050-$1,550/mo/month, 2-bedroom units for $1,300-$1,950/mo/month. Short-term rentals: Not permitted. Expected ROI: 5-7% annual return.
The minimum lot size for an ADU in San Antonio is 7,500 sq ft. 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 San Antonio, a garage conversion typically costs $50,000-$130,000. The key advantages are lower cost (no foundation work), potential setback exemptions, and faster permitting. Read our complete garage conversion guide.