ADU Pass
Davidson County
ADU Pass helps homeowners in Davidson County, Tennessee navigate the permit paperwork for building an accessory dwelling unit. We cover 8 cities and 30 ZIP codes in this county.
Map
County ADU details
County ADU ordinance
Davidson County operates as the Metropolitan Government of Nashville and Davidson County (Metro Nashville), a consolidated city-county under the Tennessee Constitution Art. XI § 9 and the Charter of the Metropolitan Government (1963; ratified by referendum). With ~715,000 residents — Tennessee's second-most populous jurisdiction (after Memphis-Shelby County) and the state-capital county — Metro Nashville encompasses the entire county including the General Services District (the consolidated jurisdiction) and the Urban Services District (a smaller subset receiving urban-level services), plus the satellite cities of Belle Meade, Berry Hill, Forest Hills, Goodlettsville partial, Oak Hill, and Ridgetop partial which retain limited independent municipal status. Metro Nashville regulates land use through the Metropolitan Code of Laws Title 17 (Zoning Code), administered by the Metropolitan Department of Codes and Building Safety and the Metropolitan Planning Department. Tennessee enacted SB 1102 (2024) authorizing local-option ADU enabling but did not preempt — Tennessee's stateAduLaw is netEffect 'no-statewide-law'. Metro Nashville adopted Specific Plan ZN District ADU rules in 2017 and expanded ADU allowances 2020-2024 in response to housing-supply pressure; the Metro Nashville zoning code now permits 'detached accessory dwelling units' (DADUs) in most single-family zone districts (RS5, RS7.5, R6, R8, R10, R15, R20, R30, R40, R80, RM2, RM4, RM6, RM9 and most SP-R Specific Plans) by-right or with administrative approval.
County assessor
Assessment policy: Davidson County Assessor (Property Assessor of the Metropolitan Government) assesses real and personal property under Tenn. Code Ann. § 67-5-101 et seq. Tennessee assesses residential property at 25% of fair market value (TCA § 67-5-901). New ADU construction is reassessed at fair market value as of January 1 following completion. Tennessee's reappraisal cycle in Davidson County is on a 4-year cycle (with the most recent in 2025). Tennessee's tax freeze (TCA § 67-5-705) is available to owners 65+ with income below thresholds, freezing the property tax at the level paid in the year of qualification. The Greenbelt program (TCA § 67-5-1004 et seq.) provides agricultural / forest / open space classification reducing assessment for qualifying parcels; not generally relevant to ADUs.
County overlays (3)
Known county issues (3)
- other — Most Davidson County ADU activity flows through Metro Nashville Title 17; satellite cities are smaller and more restrictive.
- other — Floodplain ADU economics in Davidson County are severely constrained by the +4 ft freeboard; many SFHA parcels effectively cannot host detached ADUs within zoning setbacks while elevating to compliance.
- other — Metro Nashville is among the most ADU-permissive consolidated city-counties in the South; ADU economics are favorable for long-term rental, constrained for short-term rental in many areas.
Federal (United States) — ADU-relevant rules and programs
Federal ADU law
The United States has no federal statute that directly regulates accessory dwelling unit entitlement or design. Land-use authority over ADUs resides with states and local governments under the traditional police power. Federal engagement is limited to financing (Fannie/Freddie/FHA/VA/USDA), flood insurance (FEMA/NFIP), and discretionary housing programs (HUD), which are recorded in sibling sections of this file.
Federal financing programs
Federal housing-finance agencies and GSEs set nationwide underwriting rules that govern whether an ADU can be financed, appraised, and counted toward mortgage qualifying income. The relevant actors are Fannie Mae, Freddie Mac, FHA (HUD), VA, and USDA Rural Development.
Federal tax credits
There is no ADU-specific federal tax credit. ADUs may incidentally qualify for existing federal energy-efficiency and clean-energy tax credits when the ADU construction includes qualifying measures.
Federal housing programs
HUD administers several discretionary programs that can fund ADU-related activity at the grantee's election, but none is an ADU-specific program.