What are the ADU rules inside San Antonio city limits?
San Antonio allows one ADU per property in eligible residential districts. It can be up to 800 sq ft or 50% of the main house, whichever is larger, capped at 1,600 sq ft. The owner must live in the main house or the ADU and record an affidavit with Bexar County before the permit is issued.
Which zoning districts qualify?
R-1 through R-6, RM-4, RM-5 and RM-6, plus multifamily districts where the total stays at five units or fewer, according to the city's ADU page.
Is there a statewide rule that overrides city codes?
No. Texas has no statewide ADU law as of October 2026; a 2025 bill passed the Senate but stalled in the House. That is why rules shift so much at city lines. More in our deed restrictions and state law guide.
What about unincorporated Bexar County?
Lots outside city limits do not follow city zoning, though county and utility rules, and often septic standards, apply. Send the address and we will tell you whether we can take it on.