How Knoxville Handles Accessory Structures: A Practical Guide

Knoxville maintains 127 local ordinances across all categories, and 9 of those deal specifically with accessory structures. Here is a breakdown of what the city actually requires, what is prohibited, and where Knoxville falls on the strict-to-permissive spectrum compared to other cities.

Carport Rules

Knoxville Zoning Code Article 10.3.G allows carports only over a driveway in the interior side, corner side, or rear yard. They are capped at 22 feet long, must be open on at least two sides, and must use permanent materials. A building permit is required.

Key details: Zoning Section: Art. 10.3.G. Allowed Yards: Interior side, corner side, rear. Max Length: 22 feet. Open Sides Required: At least 2. Max Height (detached): 18 feet.

Building a carport in a front yard, longer than 22 feet, enclosed on three or more sides, or without a permit violates Article 10.3.G. Plans Review and Inspections can issue stop-work orders and pursue civil penalties.

Tiny Homes

Knoxville has no separate tiny-home ordinance. A site-built tiny home is regulated as a single-family dwelling or as an accessory dwelling unit (ADU) under Article 10.3.B. Detached ADUs require a 5,000 sq ft lot, are capped at 600-1,200 sq ft, and limited to two bedrooms.

Key details: Tiny-Home Ordinance: None - regulated as ADU. Zoning Section: Art. 10.3.B. Min Lot Size: 5,000 sq ft. Max GFA Range: 600 - 1,200 sq ft. Max Bedrooms: 2.

A tiny house on wheels used as a permanent dwelling, an ADU on a lot under 5,000 sq ft, exceeding 10.3.B.8/10.3.B.9 size or bedroom caps, or violating owner-occupancy violates Article 10.3.B and can trigger stop-work orders.

ADU Impact Fees

Knoxville does not impose a dedicated ADU impact fee. Standard building permit fees through Plans Review & Inspections apply based on construction valuation, with separate trade permits for plumbing, electrical, mechanical, and gas work. Knoxville Utilities Board (KUB) tap fees apply only if a new water, sewer, gas, or electric service is required. Tennessee has no statewide ADU fee-waiver statute.

Key details: City Impact Fee: None adopted. Fee Basis: Construction valuation. Utility Provider: Knoxville Utilities Board (KUB). KUB Tap Fees: Only if new connection. Typical Total: $1,500-$4,000 city fees.

Building without paying required permit fees prevents issuance of a Certificate of Occupancy and triggers stop-work orders. Performing utility hookups without KUB authorization risks utility disconnection and back-billing. Unpermitted construction discovered later is typically assessed double permit fees as a retroactive penalty under the Knoxville Building Code.

Knoxville is more permissive than most cities when it comes to adu impact fees. That said, there are still limits.

ADU Permits

Knoxville allows one Accessory Dwelling Unit (ADU) by-right with any single-family dwelling under the Recode Knoxville Zoning Ordinance, Article 10 (Use Standards). ADUs may be internal, attached, or detached. Building permits go through the City of Knoxville Plans Review & Inspections Division. The Recode Knoxville ordinance took effect January 1, 2020 after City Council adoption on August 13, 2019.

Key details: Code Section: Recode Article 10 (Use Standards). Eligible Districts: RN-1 through RN-5, EN. ADU Types Allowed: Internal, attached, detached. Parking: +1 off-street space. Recode Effective: January 1, 2020.

Constructing or occupying an ADU without permits violates the Knoxville City Code Building Code and the Recode Zoning Ordinance, triggering stop-work orders, daily code-enforcement fines, required permitting or demolition, and KUB (Knoxville Utilities Board) disconnection risk for unpermitted utility work. Properties in H-1 historic overlay districts face additional Historic Zoning Commission enforcement.

ADU Owner Occupancy

Recode Knoxville Article 10 requires that one of the two units on an ADU property - either the principal dwelling or the ADU - be occupied by the property owner as their primary residence. Both units cannot be rented to non-owners simultaneously. Tennessee has not preempted owner-occupancy requirements, so Knoxville's rule is enforceable. Compliance is verified at permitting and during short-term rental review.

Key details: Code Section: Recode Article 10 (ADU Standards). Requirement: Owner must occupy one of the two units. Both Rented to Non-Owners: Prohibited. Verification: Affidavit + STRU review. State Preemption: None (Dillon Rule).

Renting both the principal dwelling and the ADU to non-owners violates Recode Article 10 and can result in code-enforcement citations, daily fines under Knoxville City Code, loss of Certificate of Occupancy, and required cessation of one rental. Short-Term Rental permits are revoked when owner-occupancy lapses. Knox County HOAs may impose additional CC&R-based occupancy rules.

This is not one of those rules that cities tend to ignore. Knoxville actively enforces its adu owner occupancy requirements.

ADU Rental Restrictions

Knoxville ADUs may be rented long-term only when the owner occupies the other unit on the property. Short-term rentals (under 30 days) require a Short-Term Rental Unit (STRU) permit under Knoxville City Code Chapter 16, Article XV. The ordinance distinguishes Type 1 (Owner-Occupied) from Type 2 (Non-Owner-Occupied) permits, with Type 2 restricted in residential districts. Tennessee's STR Act (TCA 13-7-602) preempts cities from banning pre-2018 STRs.

Key details: STR Code: City Code Ch. 16, Art. XV. Effective: January 2018. Type 1 (Owner-Occupied): Allowed in residential zones. Type 2 in RN Zones: Restricted/limited. State Preemption: TCA 13-7-602 (pre-2018 grandfather).

Operating an unpermitted STR in Knoxville carries citations under City Code Chapter 16, Article XV, with daily fines and required cessation. Platforms (Airbnb, VRBO) may delist properties for permit non-compliance. Renting both ADU units to non-owners separately from the principal dwelling violates Recode Article 10. Tennessee Department of Revenue separately enforces sales and occupancy tax obligations.

This is one of the stricter rules in Knoxville's municipal code. If you are unsure whether your situation complies, it is worth checking with the city before proceeding.

ADU Rules

Knoxville permits one ADU by right on any single-family lot. ADUs may be internal, attached, or detached, with standards for size, setbacks, owner occupancy, and parking.

Key details: Allowed: 1 ADU per single-family lot by right. Types: Internal, attached, or detached. Owner Occupancy: Required in primary or ADU. Permit: Building permit required.

Unpermitted ADUs must be brought into compliance. Violations of owner occupancy or other standards may result in enforcement action.

Shed Rules

Small sheds under 200 sq ft in Knoxville generally do not require a building permit. All structures must comply with zoning setbacks and height limits.

Key details: Permit Exempt: Under 200 sq ft, single story. Setbacks: Must comply with zoning. Location: Side or rear yard. Lot Coverage: Must comply with zoning limits.

Sheds violating setbacks or built without required permits face code enforcement action.

Garage Conversions

Garage conversions in Knoxville require building permits and must meet building code standards for habitable rooms. Converting to an ADU requires compliance with ADU regulations.

Key details: Permit Required: Yes, building permit needed. ADU Option: Must meet ADU standards. Building Code: Habitable room standards required. Parking: Replacement may be required.

Unpermitted conversions result in code violations. ADU conversions must comply with all ADU standards.

The Bottom Line

Knoxville is tougher than many cities when it comes to accessory structures. Out of the 9 rules covered here, 2 are rated strict. If you are a homeowner, renter, or business owner in Knoxville, take the time to understand these requirements before they become a problem. Most violations come with fines, and some repeat violations can escalate.

This guide is based on Knoxville's current municipal code. Local rules can and do change, so check the individual ordinance pages for the latest details, penalties, and FAQs.