ADU Rules in San Antonio, TX (2026)
ADU rules, permit requirements, size limits, and fees for San Antonio, TX. Source-cited from official municipal code.
Whether ADUs are allowed in San Antonio, TX has not been confirmed — see the official source before proceeding.
Whether San Antonio, TX permits accessory dwelling units (ADUs) has not been confirmed from an official source. ADUs — also called granny flats, in-law units, or secondary suites — are secondary housing units on a single-family or multifamily lot. Contact the local building department through their official website to verify current ADU rules before proceeding, as regulations may have changed since this data was last reviewed.
ADU Size Limits
ADU Size Limits in San Antonio: Detached ADU: size varies by zoning — see official source (max height: varies — see official source). Attached ADU: size varies by zoning — see official source.
| Type | Max Size | Max Height |
|---|---|---|
| Detached ADU | See official source | See official source |
| Attached ADU | See official source | See official source |
Permit Fees
ADU Permit Fees in San Antonio: Plan check fee: Varies. Building permit fee: Varies. Impact fees: None. School fees: None or N/A. Total estimated permit cost: Varies.
| Fee Type | Amount |
|---|---|
| Plan Check | $250–$1,500 |
| Building Permit | Based on construction value — typically $800–$3,500 |
| Impact Fees | $500–$3,000 depending on location and utility connections |
| School Fees | None |
| Total Estimate | See official source |
Permit Timeline
San Antonio ADU Permit Timeline: Permit timeline has not been confirmed — contact the department for current processing times. Apply through the local building department online permit portal. Contact them through their official website for current contact information.
Setback Requirements
ADU Setback Requirements in San Antonio: Front setback: follows zone standard. Side setback: no minimum. Rear setback: no minimum.
Parking Requirements
Parking Requirements: Parking requirements have not been confirmed — see official source.
Restrictions & Requirements
- Secondary dwelling unit must be on the same lot as the primary residence
- One secondary dwelling unit per residential lot
- Must comply with lot coverage limits for the applicable zone
- Cannot be sold or conveyed separately from the primary lot
- Must meet minimum setback requirements per UDC Section 35-311
- Short-term rental requires STR registration with the city
How Many ADUs Are Allowed?
Number of ADUs Allowed in San Antonio: Single-family lots: not confirmed — see official source. Multifamily properties: not confirmed — see official source.
- Single-Family Lots
- 1 secondary dwelling unit per single-family lot
- Multifamily Properties
- Not applicable as a separate accessory unit in RM zones
Statewide Preemption
ADU Preemption
We could not confirm a statewide ADU preemption statute for Texas.
View Texas preemption detailsFrequently Asked Questions
Can I build an ADU in San Antonio?
Yes. San Antonio, TX allows accessory dwelling units. On a single-family lot you can build 1 secondary dwelling unit per single-family lot.
How big can an ADU be in San Antonio?
The maximum size for a detached ADU in San Antonio is 1,000 square feet.
How long does it take to get an ADU permit in San Antonio?
The typical ADU permit timeline in San Antonio is San Antonio DSD building permit: typically 4-8 weeks plan review. Electronic plan review available through the DSDepermit portal. Construction typically 4-12 months.. Total estimated permit fees are $2,000–$8,000 total fees.
Do I need extra parking for an ADU in San Antonio?
San Antonio parking rules for ADUs: 1 parking space required per secondary dwelling unit. Parking requirements may be reduced in designated transit corridors near VIA Metropolitan Transit routes.
Do I have to live on-site to have an ADU in San Antonio?
Owner-occupancy requirement in San Antonio: 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.
Source: San Antonio Unified Development Code (UDC) Section 35-311 — Secondary Dwelling Units; library.municode.com/tx/san_antonio. Last verified April 6, 2026. View source