Arlington, TX Accessory Structures: ADU Rules (2026)

Accessory dwelling units in Arlington are governed by the city's Unified Development Code rather than any statewide housing mandate. Texas Local Government Code Chapter 211 grants cities broad authority to regulate residential zoning, and Arlington uses that authority to permit ADUs, sometimes called secondary dwelling units or garage apartments, in specific residential districts, often as a Specific Use Permit or conditional use in single-family zones. Where allowed, typical standards include a maximum floor area of 800 to 1,000 square feet or a percentage of the primary dwelling size, owner-occupancy of either the primary home or the ADU, compliance with side and rear setbacks for accessory structures (commonly 3 to 5 feet), a maximum height typically limited to 25 feet, and provision of at least one additional off-street parking space. ADUs must connect to city water and sewer, have separate addressing, and meet International Residential Code standards for a complete dwelling including kitchen, bathroom, sleeping area, and separate egress. Short-term rental of ADUs is subject to Arlington's separate STR regulations, which have been restricted in residential zones. HOA covenants in many Arlington subdivisions prohibit ADUs or restrict use of garage apartments, and deed restrictions typically prevail over zoning permissions. Applicants should start with a pre-development meeting with Arlington Planning to verify their specific property's eligibility before investing in plans.