Accessory Structures in San Antonio, TX: What Residents Actually Need to Know

If you live in San Antonio or are thinking about moving there, accessory structures are one of those things you probably won't think about until they affect you directly. San Antonio has 9 specific rules on the books covering different aspects of accessory structures, and some of them might surprise you.

ADU Owner Occupancy

San Antonio requires the property owner to occupy either the principal dwelling or the ADU as their permanent residence under UDC § 35-372. A notarized owner-occupancy affidavit must be submitted with the permit application and a covenant must be recorded with the Bexar County Clerk. Renting both units to non-owner tenants is prohibited.

Key details: Code Section: UDC § 35-372. Affidavit: Notarized, submitted with permit. Recording: Covenant filed with Bexar County Clerk. Both-Rented Allowed: No — owner must live in one unit.

Operating an ADU without satisfying owner occupancy is a code violation. DSD may revoke the certificate of occupancy and refer the matter to Municipal Court. Fines up to $500 per day apply for ongoing violations. Renting both units to non-owners can trigger STR enforcement under UDC § 35-374.01.

Compared to other cities, San Antonio takes a harder line on adu owner occupancy. The enforcement and penalty structure reflects that.

ADU Permits

San Antonio allows accessory dwelling units by right in most residential districts under UDC § 35-372 (formerly § 35-371). Applicants apply through the BuildSA Online Portal, submit a site plan, structural plans, and a notarized owner-occupancy affidavit, and record an ADU covenant with Bexar County. The Development Services Department (DSD) issues the building permit after zoning, building, and utility review.

Key details: Code Section: UDC § 35-372. Portal: BuildSA Online Portal. Detached Max: 800 sq ft (1,200 sq ft RE). Required Filings: Affidavit + recorded covenant. DSD Phone: (210) 207-1111.

Building an ADU without a permit is a Class C misdemeanor under San Antonio City Code with fines up to $2,000 per day for building code violations and $500 per day for zoning violations under Texas Local Government Code § 54.001. DSD may issue stop-work orders and order removal of unpermitted ADUs.

ADU Rental Restrictions

ADUs in San Antonio may be rented long-term but short-term rental use (under 30 days) requires a separate STR permit under UDC § 35-374.01. The owner must occupy the main house or the ADU regardless of which unit is rented. Type 1 STR (owner-occupied) permits ($300/3yrs) are required for ADU short-term rentals; Type 2 permits do not apply to owner-occupied ADUs.

Key details: Long-Term Rental: Permitted (owner must still live on-site). STR Permit Type: Type 1 ($300/3 yrs). STR Code: UDC § 35-374.01. Enforcement: 2024-06-13-0433 strengthened civil penalties.

Operating an ADU short-term rental without a Type 1 permit is a code violation with fines up to $500 per day. The 2024 enforcement amendments allow civil penalties through administrative hearings. Three violations of the STR ordinance can result in permit revocation and a multi-year prohibition.

This is one of the stricter rules in San Antonio's municipal code. If you are unsure whether your situation complies, it is worth checking with the city before proceeding.

ADU Impact Fees

San Antonio assesses standard development fees on ADUs, but utility connections typically reuse the principal dwelling's tap to limit costs. SAWS (San Antonio Water System) impact fees apply when a separate water or sewer connection is requested. CPS Energy handles separate electric service. Texas has no statewide ADU impact-fee waiver comparable to California.

Key details: Permit Fee Start: From $150 (Residential Improvements). SAWS Water Impact: ~$4,000–$6,000/EDU (new connection). SAWS Sewer Impact: ~$2,000–$3,000/EDU. State Waiver: None — no Texas ADU fee exemption.

Failure to pay required impact and utility fees results in permit denial or revocation. Operating an ADU without paid water/sewer connections can trigger SAWS service termination and code enforcement action.

Shed Rules

San Antonio follows the International Residential Code (IRC) Section R105.2: a building permit is not required for a one-story detached accessory structure 200 square feet or smaller used as a tool or storage shed, playhouse, or similar use, but UDC Section 35-516 setbacks and zoning rules still apply.

Key details: Permit Needed: No permit needed: detached one-story shed 200 sq ft or less, no. Permit Required: Permit required if over 200 sq ft, attached, or with electrical/plumbing. Setbacks: Side/rear setback: 5 feet (3 feet if no projecting features). Lot Coverage: Sheds count toward lot coverage in UDC Sec. 35-310. Setbacks: BOA variance fee: $400 for setback hardship requests.

Building a shed without a required permit (over 200 sq ft, attached, or with utilities) can result in a stop-work order, after-the-fact permit fees with penalties, and Municipal Court citations under IRC R105.1. Setback or lot-coverage violations can require relocation or removal of the structure, or a Board of Adjustment variance with a $400 hearing fee.

San Antonio is more permissive than most cities when it comes to shed rules. That said, there are still limits.

Garage Conversions

Garage conversions in San Antonio may create ADUs under UDC §35-371, subject to owner occupancy requirements. Building permits are required for all conversions. UDC parking standards must still be met — converting a garage may trigger parking deficiency issues.

Key details: Permit: Required from DSD. ADU Rules: Apply if creating dwelling. Parking: Must maintain UDC standards. Historic District: HDRC review required.

Unpermitted conversion: stop-work order. Parking deficiency: Code Compliance citation. ADU without covenant: violation of UDC §35-371.

ADU Rules

San Antonio UDC §35-371 permits internal, attached, and detached ADUs by right in rural and residential districts. Detached ADUs max 800 sq ft (1,200 in RE zones). Owner must occupy main or ADU as permanent residence. Max 3 occupants in ADU. Building permit and recorded covenant required.

Key details: Max Size: 800 sq ft (1,200 in RE). Owner Occupancy: Required on-site. Max Occupants: 3 in ADU. Setback: 5 ft rear and side.

Unpermitted ADU: citation, correction required. Owner occupancy violation: covenant enforcement. Fine $100–$2,000.

Carport Rules

Carports in San Antonio are classified as typical residential accessory structures under the UDC. They receive special exceptions in nonresidential districts where other accessory structures may be restricted. Carport setbacks follow UDC § 35-516(g), which provides specific provisions for garages and carports. The total floor area of all accessory structures may not exceed 2,500 square feet, and they must not occupy more than 30% of the required yard area.

Key details: Code Section: UDC § 35-516(g); UDC Art. III, Div. 7. Max Floor Area: 2,500 sq ft total for all accessory structures. Yard Coverage: Max 30% of required yard area. Setback: Min 3 ft from required site line. Placement: Side or rear yard in single-family districts.

Unpermitted carports: stop-work orders, required removal or retroactive permitting with penalty fees. Fines $200 to $1,000.

Tiny Homes

Tiny homes in San Antonio generally must comply with ADU (Accessory Dwelling Unit) regulations under UDC § 35-371. Detached ADUs are limited to 50% of the primary dwelling or 1,000 square feet, whichever is less, with a maximum of 1 bedroom and a height limit that cannot exceed the primary residence. Tiny homes on wheels may be classified as recreational vehicles and subject to different regulations under UDC § 35-385.

Key details: Code Section: UDC § 35-371 (ADU); § 35-385 (RV regulations). Max Size: 50% of primary dwelling or 1,000 sq ft (whichever less). Bedrooms: Maximum 1 bedroom for detached ADU. Height: Cannot exceed primary residence; max 25 ft / 2 stories. On Wheels: May be classified as RV under § 35-385.

Unpermitted dwellings: removal or retroactive permitting. Zoning violations: fines and required relocation. Occupancy without certificate: prohibited.

The Bottom Line

San Antonio is tougher than many cities when it comes to accessory structures. Out of the 9 rules covered here, 2 are rated strict. If you are a homeowner, renter, or business owner in San Antonio, take the time to understand these requirements before they become a problem. Most violations come with fines, and some repeat violations can escalate.

All of the above reflects San Antonio's municipal code as of our last review. If you need specifics on fines, exemptions, or filing requirements, the detailed ordinance pages linked above have the full breakdown.