ADU Rules in Nashville, Tennessee

Metro Nashville uses the term Detached Accessory Dwelling Unit (DADU) for the detached secondary dwelling regulated by the current zoning code.

A DADU is not automatically allowed on every residential parcel.

Parcel Eligibility

Metro's current DADU permit guide requires:

1. the parcel's zoning district to permit DADUs with conditions;
2. the lot to meet the minimum lot area for that zoning district; and
3. the parcel to be in at least one qualifying geography/framework, such as:
   • the Urban Services District;
   • a DADU overlay in the General Services District;
   • a UDO with DADU standards; or
   • an SP with DADU standards.

Only one DADU may be built on a parcel and only when there is one single-family principal structure.

Owner Occupancy

The principal structure and DADU must have the same owner, and one of the two dwellings must be owner-occupied.

Maximum Living Space

Metro's current guide states:

• lot under 10,000 sq ft: maximum 700 sq ft;
• lot 10,000 sq ft or larger: maximum 850 sq ft.

The DADU may not exceed the size of the principal structure.

Height

Current DADU controls include:

• one-story maximum eave height: 10 ft;
• two-story maximum eave height: 17 ft;
• roof ridge must be lower than the principal structure and may not exceed 27 ft.

Setbacks

For an accessory building/DADU with a footprint of 850 sq ft or less located behind the principal structure:

• side setback: one-half the underlying district requirement, but not less than 3 ft;
• rear setback: at least 3 ft;
• if a garage door or carport opening faces directly onto an alley, rear setback: 10 ft.

Other easements and platted setbacks still apply.

Short-Term Rentals

Metro's current DADU page contains specific restrictions on short-term-rental use. Do not assume a newly created DADU can automatically be used as an STR.

Official Source

Metro Nashville — Detached Accessory Dwelling Unit Permit Guide

Disclaimer: Verify the parcel's zoning, lot area, service district/overlay status, and current code before preparing a DADU design.