Can I Build ADU in San Antonio, TX? (2026)
Find out if you can build a adu in San Antonio, TX. Rules, permit requirements, costs, and next steps.
Yes, ADUs are allowed in San Antonio, TX. California state law ensures by-right approval.
An Accessory Dwelling Unit (ADU) is a secondary housing unit on a residential lot — also called a granny flat, in-law suite, or backyard cottage. In San Antonio, TX, ADUs are permitted by right under state law, making them one of the most accessible ways to add housing on your property. ADUs can be detached, attached to the main home, or created by converting an existing garage or accessory structure.
ADU Rules in San Antonio
ADU Rules in San Antonio: Detached ADU max size: 1000 sq ft. Attached ADU max size: No greater than 50% of main dwelling floor area. Setbacks: 5 ft side, 5 ft rear. Owner-occupancy: San Antonio UDC does not require owner-occupancy for secondary dwelling units in most residential zones. Owner may rent out both the primary and secondary units..
Costs & Fees
ADU permits in San Antonio: Total estimated permit cost: $2,000–$8,000 total fees. Contact the City of San Antonio Development Services Department (DSD) for current fee schedule.
Timeline
San Antonio DSD building permit: typically 4-8 weeks plan review. Electronic plan review available through the DSDepermit portal. Construction typically 4-12 months.
Next Steps
Next steps for building an ADU in San Antonio: 1. Review full ADU rules including size limits, setbacks, and parking. 2. Apply for an ADU permit through the City of San Antonio Development Services Department (DSD) at https://www.sanantonio.gov/DSD/Permits/PermitPortal. 3. Hire a licensed contractor familiar with TX ADU requirements.
City of San Antonio Development Services Department (DSD)
Phone: (210) 207-1111
Website: https://www.sanantonio.gov/DSD
Online Permits: https://www.sanantonio.gov/DSD/Permits/PermitPortal
Frequently Asked Questions
Can I build a secondary dwelling unit (ADU) on my San Antonio property?
Yes. San Antonio allows secondary dwelling units on most residential lots under the Unified Development Code (UDC) Section 35-311. The unit can be up to 1,000 sqft for detached units. No owner-occupancy requirement in most zones. You'll need a building permit from the Development Services Department (DSD). SAWS (San Antonio Water System) connection fees apply for new utility service.
What zone is my San Antonio property in?
Use the San Antonio GIS Zoning Map at gis.sanantonio.gov/DSD/ZoningMap to look up your property's zoning designation. The city uses R-1 through R-6 for single-family and RM-4 through RM-6 for multifamily residential zones. You can also contact DSD at (210) 207-1111 for zoning verification.
Are short-term rentals (Airbnb) allowed in San Antonio?
Yes, with registration. San Antonio requires STR registration for all rentals of 30 days or fewer. The fee is $200/year. Both owner-occupied and non-owner-occupied STRs are allowed with registration. Hotel Occupancy Tax (HOT) must be collected. Your registration number must appear on all booking platform listings. Noise ordinance and occupancy limits apply.
Does San Antonio have historic district restrictions?
Yes. San Antonio has some of the strongest historic preservation rules in Texas. If your property is in a local historic district (King William, Lavaca, Government Hill, and others) or is a designated landmark, exterior alterations require a Certificate of Appropriateness from the Historic Design and Review Commission (HDRC). The process applies to all exterior changes including additions, new construction, and demolition.
What are the utility providers in San Antonio?
CPS Energy (City Public Service) provides electricity and natural gas for San Antonio. SAWS (San Antonio Water System) provides water and wastewater service. Both are city-owned utilities. CPS Energy handles interconnection for solar installations and offers net metering. New SAWS connections and impact fees apply when adding dwelling units.
Does San Antonio charge impact fees for residential development?
Yes. Unlike Dallas, San Antonio does charge impact fees for residential development. Fees depend on location and the type of utility connection required. SAWS (San Antonio Water System) charges connection fees for new water and wastewater service. Contact San Antonio DSD and SAWS for current fee schedules before planning a project.
Source: City of San Antonio Development Services Department (DSD) — Building Regulations. Last verified April 6, 2026. View source