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Knoxville, TN Accessory Structures: ADU Rules (2026)

Some Restrictions

Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

ADU rules in Knoxville, TN, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.

Key Facts

Min lot size: 5,000 sq ft
Max ADU size: 40% of primary dwelling
Max bedrooms: 2 bedrooms
Owner occupancy: One unit owner-occupied required
Citation: Appendix B § 10.3.B

ADU Eligibility Quick-Check

An Accessory Dwelling Unit (ADU) is a smaller, independent living unit on the same lot as a single-family home: converted garages, detached cottages, basement or attic conversions, and attached additions all qualify. Most states have streamlined ADU permitting since 2020, but local rules still control size, height, and setback.

Is your lot zoned single-family or multi-family residential?
Does your lot have at least 1,200 sq ft of buildable space?
Is your existing home owner-occupied (in most states this is not required, but some require it for ADU permits)?
Will the ADU stay under your state's size cap (commonly 850-1,200 sq ft for detached)?
Can you provide one off-street parking space (waived in many states within 0.5 mi of transit)?

If you answered 'yes' to most of these, you likely qualify in Tennessee under recent ADU streamlining laws. The Knoxville, TN rules below cover local size, height, and setback requirements.

Summary

Knoxville allows one accessory dwelling unit per single-family lot of at least 5,000 square feet, capped at 40% of the primary home's floor area and two bedrooms, under the zoning code.

B. Accessory Dwelling Unit (ADU) 1. The design and size of the accessory dwelling unit (ADU) must conform to all applicable building codes. 2. An ADU may be located only on a lot with one single-family dwelling. [...] One of the dwelling units must be occupied by the owner of the property. 3. A lot must have a minimum area of 5,000 square feet to qualify for an ADU. 4. Only one ADU is permitted per lot. [...] 7. In no case may an ADU exceed 40% of the primary dwelling floor area nor more than 2 bedrooms.

View official code

Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 80).

Full Breakdown

An ADU is allowed on a lot with one single-family dwelling, and the property owner must occupy one of the two units. The lot needs at least 5,000 square feet, and only one ADU is permitted per lot. It can be built within, attached to, or fully detached from the primary home, but a detached ADU can't sit in the front yard or corner side yard. Size is capped at 40% of the primary dwelling's floor area and no more than two bedrooms. The ADU has to keep the primary structure looking like a single house, its entrance must stay unobtrusive, and one off-street parking space is required for the unit.

Violations & Fines

Adding a second ADU on a lot, building one over 40% of the primary home's floor area, or skipping the owner-occupancy requirement violates Appendix B § 10.3.B and can block a certificate of occupancy.

Frequently Asked Questions

Do I need to live on the property to have an ADU in Knoxville?

Yes: the property owner must occupy one of the two dwelling units under Appendix B § 10.3.B; the ADU can't be a standalone rental with an absentee owner.

How big can a Knoxville ADU be?

No larger than 40% of the primary dwelling's floor area and no more than two bedrooms, per § 10.3.B.7 of the zoning code.

Sources & Official References

[1]Knoxville City Code, Appendix B (Zoning Code), Recode Knoxville

Other rules in Knoxville

Parking Rules: Overnight ParkingSome Restrictions Parking Rules: Street Parking LimitsSome Restrictions Shed & Carport RulesSome Restrictions ADU Owner OccupancySome Restrictions Noise Ordinances: Leaf Blower RulesLight Restrictions Parking Rules: Towing & Impound RightsSignificant Restrictions Parking Rules: Curb Color RulesSome Restrictions Parking Rules: Commercial & Oversized VehiclesSome Restrictions

All Knoxville rules

How Knoxville compares: Easiest Cities to Build an ADU·Compare Knoxville to another location·View the Tennessee accessory structures overview

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