Everything homeowners ask about building an ADU in Nashville — answered with 2026 data.
Sometimes — but not by right. Inside the Urban Services District a DADU has been permitted with conditions on any RS, R, RM or AG lot since December 12, 2025 (BL2025-1007): no overlay, no hearing, just a zoning examiner's check of Metro Code 17.16.030.G. In the General Services District, which covers the county's outer suburbs, a DADU is allowed only where a council-adopted DADU overlay, an SP or a UDO provides for one. Zoning: Permitted with conditions (PC) in AG/AR2a, RS80 through RS3.75-A, R80 through R6-A, RM2 through RM100-A-NS and OR20 through ORI-A-NS districts (17.08.030 land-use table as amended by BL2025-1007 Exhibit A), but only on lots inside the Urban Services District, inside a DADU overlay in the General Services District, or in an SP/UDO with DADU standards (17.16.030.G.11). The lot must hold exactly one single-family principal structure. Because approval is discretionary, confirm your own parcel with the planning department before budgeting. See our full Nashville ADU rules page.
ADU construction in Nashville typically costs $200,000-$300,000. The cost per square foot averages $250-$475. Garage conversions are more affordable at $70,000-$120,000, while prefab ADUs cost $200,000-$400,000. Permit fees add $5.00 per $1,000 of construction value (Metro Code 16.28.110.A.1) plus a $25 zoning exam fee and a 10% Codes tech fee; no plan-review fee for one- and two-family work. A 700 sq ft DADU valued on the ICC table at $169.09/sq ft (about $118,000) comes to roughly $675 before trade permits to your budget. See our detailed Nashville ADU cost guide.
Detached ADUs in Nashville can be up to 700 sq ft of living space on lots under 10,000 sq ft; 850 sq ft on lots of 10,000 sq ft or more; never larger than the principal house. Attached ADUs are limited to Not a category in Metro's code: a unit above a garage or attached to a workshop is still a DADU. Junior ADUs (JADUs) have a cap of N/A. Metro Nashville has no junior ADU category; an accessory apartment within the house is a separate use with its own Chapter 17.16 standards and a 1-space parking requirement (Table 17.20.030). Maximum height is Eave no higher than the house's eave line and at most 10 ft for a one-story or 17 ft for a two-story DADU, measured from average finished grade; ridge lower than the house's and at most 27 ft (17.16.030.G.7.b-c). A second-story unit needs interior, fire-rated stairs (G.9.b). You are allowed up to 1 DADU per lot, and only where a single single-family principal structure stands; two principal structures on a lot means no DADU; the DADU can never be split from the ownership of the house on a qualifying lot.
Rear setback: 3 ft minimum for a DADU with a footprint of 850 sq ft or less located behind the house; 10 ft where garage or carport doors open directly onto an alley; a footprint over 850 sq ft must meet the full district rear setback (17.12.040.E.1.a). No building over an easement or a platted setback. Side setback: One-half of the zoning district's side setback but never less than 3 ft, for a footprint of 850 sq ft or less behind the house; the full district setback applies above 850 sq ft (17.12.040.E.1.a). On a corner lot the full side-street setback of Table 17.12.030.A applies. Front setback: Not allowed in front: a DADU may only be located behind the principal structure in the rear buildable area of the lot (17.16.030.G.5). Note that garage conversions may be exempt from setback requirements if the existing structure is already within the setback area.
1 off-street space for the DADU, in addition to the house's 2 (Table 17.20.030 as amended by BL2025-1007 Exhibit B; no maximum in the UZO). A lot without alley access gets one curb cut and one driveway no wider than 12 ft serving both units; a lot with an alley must take any new access from the alley (17.16.030.G.6). Many cities and states have been relaxing ADU parking requirements in recent years. In California, no additional parking is required for ADUs near transit.
Required: the DADU must be owned by the same person or entity as the house and one of the two dwellings must be owner-occupied (17.16.030.G.3.d); a restrictive covenant saying so is recorded with the Register of Deeds ($12) before the permit issues (G.10). Note that owner-occupancy rules vary by state law — California and several other states have eliminated this requirement for standard ADUs.
The ADU permit review timeline in Nashville is typically Not published: Metro Codes posts no review-time target for residential permits. The permit issues once the zoning examiner's checklist of agency sign-offs is complete and the covenant is recorded; Codes says to allow plenty of time and to track the application in ePermits. Plan check: The plans-examination fee is waived for one- and two-family permits (16.28.110.G.2). Codes does not normally require construction drawings for houses under 5,000 sq ft; a DADU still needs the site plan, four-corner elevations and floor plan for the zoning examiner, and building, electrical, plumbing, energy and gas/mechanical compliance is checked by field inspection. Pre-approved plans availability: None. Metro Nashville offers no pre-approved DADU plans; the design must match the house's style, roof form and pitch and material colors, with dormers covering no more than 50% of the roof and set back at least 2 ft from the exterior wall (17.16.030.G.8).
Average ADU rental income in Nashville: 1-bedroom units rent for $1,600-$1,750/month, 2-bedroom units for $1,850-$2,100/month. Short-term rentals: No for new DADUs on single-family (RS), RN or RL lots: owner-occupied short-term rental (STRP) is not a permitted use in a DADU built or converted from an accessory structure after December 12, 2025 (17.16.030.G.12); the. Expected ROI: A 700 sq ft one-bedroom DADU renting at $1,600-$1,750/mo on a $200,000-$300,000 build is a 6-10% gross yield, or a 10-15 year payback before taxes, vacancy, insurance and financing.
The minimum lot size for an ADU in Nashville is No DADU-specific minimum since December 12, 2025 (the former 15,000 sq ft and alley-access rules are gone); the lot must meet the minimum lot area of its own zoning district in Table 17.12.020.A (17.16.030.G.2). 10,000 sq ft is only the line between the 700 and 850 sq ft size caps. This applies to detached ADUs — garage conversions and JADUs may have different or no lot size requirements.
Garage conversions are one of the most popular and affordable ADU options. In Nashville, a garage conversion typically costs $70,000-$120,000. The key advantages are lower cost (no foundation work), potential setback exemptions, and faster permitting. Read our complete garage conversion guide.
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