ADU Rulebook

City · Tennessee

ADU rules in Knoxville

4 sources

These are the primary sources for accessory dwelling unit regulations in Knoxville: the city's own zoning code, planning department pages, and permit guides. Start here before talking to anyone: the rules below are what your permit reviewer will apply.

Rules at a glance

Detached (backyard) ADU
Allowed

The ADU may be within, attached to, or detached from the primary dwelling and may be part of a detached accessory structure, in an existing structure or as new development. A detached ADU is not permitted in a front yard or corner side yard, and detached accessory structures are capped at 18 feet in height with 5-foot setbacks from lot lines.

Zoning Code (App. B) 10.3.B.5, 10.3.B.6, 10.3.A.4, 10.3.A.5
Attached or internal ADU
Allowed

Internal and attached ADUs are expressly allowed; the ADU must be designed so the appearance of the primary structure remains that of a house, with an unobtrusive entrance.

Zoning Code (App. B) 10.3.B.5, 10.3.B.8
Maximum size
40% of the primary dwelling's floor area, maximum 2 bedrooms; detached ADUs in accessory structures are also bound by the accessory-structure coverage chart (750 sq ft on lots of 15,000 sq ft or less, 900 sq ft up to one acre, 1,100 sq ft over one acre, or the primary structure's building coverage if less)

10.3.B.7 sets the 40% and 2-bedroom caps for all ADUs; 10.3.A.6 sets the per-structure coverage caps that apply to detached accessory structures.

Zoning Code (App. B) 10.3.B.7, 10.3.A.6
Owner occupancy
Required

One of the dwelling units (primary dwelling or ADU) must be occupied by the owner of the property.

Zoning Code (App. B) 10.3.B.2
Extra parking
1 off-street space required for the ADU

One off-street parking space is required for the ADU, in addition to parking for the primary dwelling.

Zoning Code (App. B) 10.3.B.9
Approval process
Permitted use

ADUs are a by-right accessory use on lots with one single-family dwelling; Section 10.3.B imposes standards but no special-use or use-on-review approval. In EN (Established Neighborhood) districts, ADUs are permitted unless the neighborhood prohibits them in a new approved EN application. Building permit and building-code compliance required.

Zoning Code (App. B) 10.3.B.1, 10.3.B.2, 10.3.A.2
Rental restrictions
No minimum lease term in the zoning code. Short-term rental of an ADU requires a city STR operating permit; on a property with an accessory dwelling structure, the Type 1 (owner-occupied, residential district) permit can cover either the primary dwelling or the ADU, but not both.

Type 1 STR permits are limited to natural persons using the property as their principal residence, one permit per person citywide; permit fee $70.

Code of Ordinances Sec. 16-613(a)(1)-(2), Sec. 16-614
The fine print: 6 caveats that can change the picture
  • Minimum lot area of 5,000 sq ft required to qualify for an ADU (10.3.B.3).
  • ADUs are allowed only on lots with one single-family dwelling; only one ADU per lot (10.3.B.2, 10.3.B.4). Lots developed under the Middle Housing Standards (Article 4.6) cannot have multiple principal buildings, and the single-family-dwelling limitation excludes ADUs from duplex and middle-housing lots.
  • In EN (Established Neighborhood) districts, ADUs are permitted unless the specific neighborhood's approved EN application prohibits them (10.3.B.2).
  • Detached ADUs carry accessory-structure limits: not in front or corner side yards, max 18 ft height (not exceeding the principal structure), 5 ft setbacks, and the lot-size-based coverage chart in 10.3.A.6; through lots have a special 'through lot rear' setback rule (10.3.A.3.d).
  • Design control: the primary structure must keep the appearance of a house and the ADU entrance must be unobtrusive from the view containing the principal entrance (10.3.B.8).
  • Section 10.3 last amended by Ord. O-25-2024 (Mar 5, 2024); code read as codified through Ord. O-147-2025 (Nov 25, 2025), Supplement 80.

Summarized from Knoxville's ordinance text, read July 2026; every row links the code section it came from. Rules often vary by zone and lot, so treat this as orientation, not a permit determination, and confirm with the planning department before you commit to a design.

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ADU regulations

Short-term rental rules

Planning to rent your ADU on Airbnb or VRBO? Knoxville regulates short-term rentals separately; check these before counting on nightly rental income.

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