Plano, TX Accessory Structures: ADU Permits (2026)

Plano regulates accessory dwelling units through its Zoning Ordinance, administered by the Planning Department and Building Inspections. Plano's residential districts (SF-6, SF-7, SF-9, SF-20, SF-A) historically permit a 'guest house' or 'servant's quarters' as an accessory use, but the accessory structure must be incidental to the principal single-family dwelling and cannot be rented as a separate dwelling unit. The Plano Zoning Ordinance defines a single-family dwelling as one dwelling unit per lot, which has been a barrier to ADUs as commonly understood in other jurisdictions. Establishing a true ADU as a separate dwelling unit typically requires a Specific Use Permit (SUP) — a discretionary land-use review with Planning & Zoning Commission recommendation and City Council approval, requiring public hearings and 200-foot neighborhood notification. Texas Local Government Code Chapter 211 grants Plano (as a home-rule city) zoning authority and has not preempted local ADU rules the way California has. Plano enforces the 2021 International Residential Code (with Texas amendments) through Building Inspections. Plano's tornado-prone location places it in ASCE 7 Risk Category II with Wind Zone IV (250 mph) considerations — engineered designs may be required for detached structures over certain sizes.