Knoxville, TN Accessory Structures: ADU Permits (2026)

Under Recode Knoxville Article 10, the city permits one ADU by-right in association with any single-family dwelling on a conforming lot. The ADU may take three forms: internal (carved out of the existing principal dwelling), attached (sharing a wall with the principal dwelling), or detached (a freestanding accessory structure). Eligible districts include the Residential Neighborhood districts RN-1, RN-2, RN-3, RN-4, and RN-5, as well as the Estate Residential (EN) districts. The ADU must be subordinate to the principal dwelling, may not be subdivided onto its own lot, and is subject to the accessory-structure setback and height limits of the underlying zone (typically a 5-foot minimum side and rear setback for detached structures). At least one additional off-street parking space is required. Applicants submit plans to Plans Review & Inspections; gas, plumbing, electrical, and mechanical work require separate trade permits. Tennessee has no statewide ADU by-right preemption (Dillon Rule), so Knoxville retains full local control.