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Sumner County, TN Accessory Structures: ADU Rules (2026)

Some Restrictions

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

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

Key Facts

Governing Rule: Zoning Resolution Sec. 1101(R)
Owner-Occupancy: Required, one per lot
No Rentals: Family or guests only
Min Size: 300 square feet detached
Land Needed: 20,000 sewer / 40,000 septic

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 Sumner County, TN rules below cover local size, height, and setback requirements.

Summary

Sumner County allows accessory dwelling units in any residential zone in connection with a single-family home, under Zoning Resolution Section 1101(R). By-right ADUs must be owner-occupied, at least 300 square feet, and limited in size; others need a Board of Zoning Appeals special exception.

City-specific rules exist: Hendersonville has its own adu rules rules that differ from Sumner County's county-level regulations. If you live in Hendersonville, check the city-specific page instead.

ADUs are permitted in any residential zoning district in connection with any lawfully existing single family dwelling. There are two (2) categories of ADUs: By-right and ADU's requiring Special Exception Permits.

Source: Tennessee Code AnnotatedView official code

Full Breakdown

Unlike much of Tennessee, Sumner County has clear ADU rules in Zoning Resolution Chapter 11, Section 1101, Subsection R. An ADU is a second living unit added to, inside, or detached from a single-family dwelling. It is allowed in any residential district, but the owner must live in either the principal home or the ADU, only one ADU is permitted per lot, and it cannot be rented or leased; occupancy is limited to family members or invited guests. Detached ADUs must be at least 300 square feet, cannot exceed the main house, and need 20,000 square feet of land on sewer or 40,000 on septic. A recorded covenant, plot plan, and TDEC septic verification are required before the building permit.

Violations & Fines

Establishing or occupying an ADU that fails the Section 1101(R) standards without a Board of Zoning Appeals special exception is a zoning violation. Renting an ADU breaches the required covenant and can revoke the approval.

Frequently Asked Questions

Can I build an ADU in Sumner County?

Yes, in any residential zone tied to a single-family home under Section 1101(R). The owner must live on-site, it can't be rented, and detached units need at least 300 square feet.

Can I rent out my ADU?

No. Sumner County requires a recorded covenant limiting the ADU to family members or invited guests. It cannot be used as a rental or leased unit.

Sources & Official References

[1]Tennessee Code Annotated

Other rules in Sumner County

Shed & Carport RulesSome Restrictions Parking Rules: RV & Boat ParkingSome Restrictions Garage ConversionsSome Restrictions Tiny HomesSome Restrictions Noise Ordinances: Amplified Music & Outdoor SoundSome Restrictions Noise Ordinances: Decibel LimitsSome Restrictions Parking Rules: Driveway RulesSome Restrictions Parking Rules: Loading ZonesSome Restrictions Fence Regulations: Retaining WallsSome Restrictions

All Sumner County rules

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

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ADU Rules in Cities Across Sumner County

Hendersonville, TN