Baytown, TX Accessory Structures: ADU Rules (2026)

Subsec. 35(E)(2), Accessory Dwelling Units (ADUs), of Baytown's Unified Land Development Code permits one ADU per property as an accessory use to a single-unit detached or single-unit attached home in the MR, UR, MUN, DTA, and SJ zoning districts, as well as other residential districts. The code recognizes two types: integrated ADUs, built inside or added onto the existing house, and detached ADUs, built inside a separate structure such as a detached garage. Integrated ADUs cannot involve exterior design changes that make the unit obvious from the street: any exterior door has to look like an ordinary secondary residential entrance, exterior stairs serving as the primary ADU entrance must sit on the side or rear of the house, and only one entrance may face the street unless the house already had more than one before the ADU was added.

Detached ADUs cannot be placed inside a manufactured home, recreational vehicle, travel trailer, or camper, and where an improved alley runs alongside the lot, the ADU's vehicle access has to come from the alley rather than the street. The maximum floor area of a detached ADU, measured only within the ADU itself and excluding any workshop or garage space not incorporated into the unit, is 50 percent of the principal house's total square footage or 1,000 square feet, whichever is less. 32.