ADU Rules in San Antonio, Texas

San Antonio regulates accessory dwelling units through the Unified Development Code (UDC) and current Development Services guidance.

Development Services maintains Information Bulletin 402 — Accessory Dwelling Units. The bulletin listing was updated April 2, 2026, so applicants should use the current bulletin together with the current UDC rather than relying on older summaries.

Detached ADU Standards

UDC §35-371 provides standards for detached accessory dwelling units. The published code provisions include:

• Floor area: at least 300 sq ft and no more than 800 sq ft.
• Bedrooms: no more than one bedroom.
• Number: one accessory unit per lot.
• Location: in the rear yard.
• Height: no more than 25 ft or two stories.
• Side/rear setback: 5 ft; the code provides a 3 ft option where the structure has no overhang.
• Additional design and parking provisions apply.

Attached ADUs

Attached accessory dwelling units are governed separately under §35-371 and must comply with the applicable primary-structure setback requirements.

Do not apply the detached-unit 800 sq ft rule automatically to every attached ADU.

Owner Residency and Permitting

San Antonio's Development Services ADU permitting materials require an owner-residency affidavit as part of the process. Because the City updated its ADU bulletin in 2026, applicants should confirm the current affidavit and application requirements before filing.

How to Verify a Property

1. Confirm the zoning district and any overlays.
2. Review current UDC §35-371.
3. Open the current Development Services IB 402.
4. Confirm owner-residency documentation and permit requirements.
5. Submit through the current BuildSA/Development Services process.

Official Sources

San Antonio Development Services

Development Services — current Information Bulletins

San Antonio Unified Development Code

Disclaimer: UDC amendments and Development Services bulletins can change. Verify the current §35-371 text and IB 402 before designing or permitting an ADU.