Plano, TX Accessory Structures: ADU Rules (2026)

Adopted by Ordinance No. 1800's general rules require the backyard cottage to be located on the same lot as the main dwelling unit, prohibit selling it separately from the main dwelling, and cap each lot at one backyard cottage. The dimensional standards set a 6,000-square-foot minimum lot size; a height ceiling that must not exceed the height of the main residential building; a minimum backyard cottage building floor area of 400 square feet; a maximum building floor area of 1,100 square feet or 50% of the gross habitable floor area of the main dwelling unit, whichever is more restrictive, and never exceeding the maximum lot coverage of the governing zoning district; and a minimum 10-foot separation from the main dwelling unit.

2P, to be architecturally compatible with the main house, to be built on a permanent foundation, and bar temporary buildings from serving as backyard cottages. Driveway and parking rules layered onto the same section restrict front-yard driveway access to designs consistent with the block's prevailing pattern, cap curb cuts at 24 feet, and specifically prohibit meeting the cottage's required off-street parking through tandem spaces.