ADUs are allowed in San AntonioTypes:DetachedInternal
Types:DetachedInternal
Accessory Dwelling Unit (ADU) Rules for San Antonio, TX
Is your property eligible for an ADU?
# of Properties
371,214
Owner-occupied
94%
Zoning districts
259
Avg Home Value
$266,921
Median Lot Size
0.17 acres
Avg Income
$79,351
Residential Types:
371,214 housing units
Single Family
100%
Zoning Districts:
435,413 parcels · 259 districts
R-6
33%(142,367)
R-4
20%(88,369)
R-5
18%(76,408)
R-6-PUD
6%(27,174)
Other
23%(101,095)
ADU Rules
What can you build in San Antonio, TX?
San Antonio, TX follows state and local rules for Accessory Dwelling Units. Here is a concise overview of the local rules.
Eligibility
- –Internal / Attached ADU: By Right
- –Detached ADU: By Right
Interior / Attached ADU Size Limits
- –Maximum size is the lesser of 800 sq ft or 50% of the primary dwelling’s gross floor area (excluding porches), further capped at 1,600 sq ft; in the RE district the maximum is 1,200 sq ft.
Detached ADU Size Limits
- –Maximum size for detached ADUs: 1,200 sq ft in RE and FR districts; otherwise the greater of 800 sq ft or 50% of the primary home’s gross floor area, capped at 1,600 sq ft.
Max Units
- –Detached ADU: 1 per lot (most districts)
- –FR district: 2 detached per property
Owner Occupancy
- –Owner must occupy the principal or ADU as permanent residence.
Parking
- –1 space per ADDU >800 sq ft; no minimum for smaller or attached ADDUs; waivers/reductions in UD, TOD, IDZ, and R-1 districts (up to 50% in some zones)
Rental Restrictions
- –STR stays must comply with the City STR ordinance (less than 30 days); Type 2 permits are time-limited up to 3 years and density capped at 12.5% of units on a block face. The owner-occupied unit cannot be rented; the owner must reside in either the principal unit or the ADU.
ADU State Law
What can you build in Texas?
- –Texas does not have a statewide ADU law. ADUs are regulated entirely at the local level.
- –ADU rules vary significantly by city, and many jurisdictions prohibit ADUs outright.
- –Counties generally lack zoning authority, but other restrictions may still apply outside city limits.
- –Outside city limits, ADU feasibility often depends on subdivision rules, deed restrictions, and septic or fire requirements.
- –Building/fire codes are set statewide, but whether an ADU is allowed is local zoning.
What's allowed on your lot?
These are the municipality-wide rules. What's allowed on a specific property also depends on state laws, setbacks, floor area ratio, lot coverage, environmental constraints, topography, and other property-specific factors. Search your address on FutureLot to see what's allowed on your property.
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Learn the key rules and size limits for ADUs
Is your property eligible for an ADU?
ADU rules in other Texas municipalities
Rules change at the town line. Check the municipality your property is actually in.
Bexar County
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