Accessory Dwelling Unit (ADU) Permits

The City of San Antonio adopted the Strategic Housing Implementation Plan. It provides quality affordable housing to residents at all income levels. Accessory Dwelling Units (ADUs) can help with affordable housing in San Antonio. An ADU is smaller home located on the same lot as a larger, main house. ADUs can also provide an extra source of income for homeowners. They offer aging in place opportunities and housing options for family or friends. Learn more about the ADU program.

ADU Development Requirements

Owner Occupancy
  • Owner must reside at the main house or in the ADU
  • Properties where owner does not live on site must be rezoned to allow more than one dwelling unit.
  • To learn more about property zoning, contact DSD's Zoning team or check the OneStop map.
Permitted Zoning Districts
  • R-1, R-2, R-3, R-4, R-5, R-6, RM-4, RM-5, RM-6 and in multi-family districts up to a total of five units
  • In zoning districts that allow ADUs, only one ADU is permitted to be built on the property.
Size
  • Up to 800 square feet or 50% of the size of the main house (whichever is larger)
  • Cannot exceed 1,600 square feet
  • All properties, regardless of main home size, can have an ADU of at least 800 square feet.
  • Applies to attached and detached ADUs
Bedrooms

No limit on number of bedrooms

Utilities

Can have separate utilities (meters) or can share meter with main house

Height
  • Detached ADUs are limited to 2 stories and 25 feet in height.
  • Attached ADUs must comply with height limit restrictions for the underlying zoning district.
Setbacks
  • A setback is the minimum distance a structure must be from the property line.
  • Detached ADUs may be located 3 feet or more from side and rear property lines.
    • Cannot have an eave overhang within 3 feet of the property line
    • Must be fire rated if within 5 feet of the property line
  • To avoid above measures, setbacks from side and rear property lines must be 5 feet.
Parking

Only ADUs over 800 square feet require a dedicated off-street parking space.

Apply

Step 1.Complete Affidavit

Complete an affidavit acknowledging the property owner must live on the property for the legal use and occupancy of the Accessory Dwelling Unit (ADU). An affidavit is a written statement from a person that they sign and swear is correct. This affidavit must be recorded in Bexar County's public records.

An application for an ADU and sample affidavit and covenant are available online.

Affidavit and Covenant

Step 2.Required Documents

Besides permit-ready plans, there are additional items to submit before getting a permit.

  • site plan
  • foundation plan
  • energy report must comply with adopted International Energy Conservation Code (IECC)
  • calculations for mechanical HVAC sizing (Manual J, IECC R403.7)
  • a list of proposed mechanical system equipment (Manual S, ECC R403.7)

More information can be found in IB 101 - New Residential Permit Information (PDF)

Step 3.Apply for Permit

Apply for your permit application through BuildSA.

  1. Click on Residential Building Permit Application.
  2. Complete your affidavit and provide proof or residency. Include proof that the affidavit was recorded in Bexar County as part of the application packet.

Apply Now

Step 4.Pay the Plan Review Fee

The plan review fee is invoiced, and once paid, the application is automatically routed to a plan reviewer. This technical review can take up to three business days for the initial redline comments. Redline comments are comments from a reviewer saying what edits should be made to a document. Once approved, additional permit fees, which are separate from the plan review fee, are applied to the application. After you pay these additional fees, the permit is issued.

NOTE: Some fee waivers may apply.

Step 5.Receive Permit

Inspectors review construction for compliance with adopted building codes. Once all inspections pass, a Certificate of Occupancy is issued, and the ADU may be occupied.

Fee Waivers

Construction of an ADU may qualify for waiver of city development and permitting fees, and SAWS water and wastewater impact fees.

To qualify, either the main home or the ADU must be rented to a household earning at or below 80% AMI, and rent may not exceed 30% of the renter's monthly income. This restriction must remain in place for 5 years after issuance of a Certificate of Occupancy. For more information, visit COSA Fee Waiver Program.

Contact

Email

Contact Form

Phone

210-207-1111

Address

Cliff Morton Development and Business Services Center (One Stop)
1901 S. Alamo St.
San Antonio, TX 78204
Directions

Information about visiting our office.

Hours

Monday - Friday: 7:45 a.m. - 4:30 p.m.

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