ADU Design in New Johnsonville, TN

ADU Design in Tennessee: what governs your project

Tennessee has no statewide ADU statute; ADUs are governed by each municipality's zoning ordinance. Nashville, Memphis, Knoxville, and Chattanooga each maintain their own accessory-dwelling rules within their codes.

Energy code

Permitting varies by jurisdiction: common local requirements include size caps tied to the primary home, setback and height limits, and standard building permits. Some cities require owner occupancy of one unit.

Permitting & plan check

Building permits and inspections are handled by local city and county building departments, with larger jurisdictions such as Nashville, Memphis, Knoxville, and Chattanooga running full permitting operations. The State Fire Marshal's office reviews certain occupancies. Local amendments are common, so confirming the adopted code edition with the AHJ is standard practice.

Good to know

• The Memphis area sits within the New Madrid Seismic Zone, carrying the highest seismic design categories in Tennessee.
• The 2010 flooding of the Cumberland River in Nashville reshaped floodplain awareness and flood-resistant design practice across Middle Tennessee.
• Karst topography and sinkholes are widespread in Middle and East Tennessee, making geotechnical investigation a routine part of site development.

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