Complete 2026 cost breakdown: construction, permits, financing, and expected rental ROI.
Calculate your Nashville ADU cost →Building an ADU in Nashville costs between $200,000-$300,000 for new construction, with per-square-foot costs averaging $250-$475. These figures include design, permitting, site preparation, and construction. The most affordable option is a garage conversion at $70,000-$120,000, while prefab/modular ADUs fall in between at $200,000-$400,000.
| Cost Category | Estimated Range |
|---|---|
| Architectural Plans | $3,000 – $15,000 |
| Permits & Fees | $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 |
| Impact Fees | No development impact fee appears in the Codes fee schedule, but Metro Water Services charges capacity fees of $1,375 (water) and $2,300 (sewer) per 350-gallon-per-day unit of flow, a stormwater capacity fee of $0.71 per sq ft of new impervious area, and tap fees if the DADU gets its own meter ($500 for a 5/8-inch water tap, $360 for a 6-inch sewer tap) (MWS Development Fee Schedule, Schedule 15.10.110, rev. January 28, 2025). Ask MWS how many units of flow your DADU is assessed |
| Site Prep & Foundation | $10,000 – $35,000 |
| Framing & Structure | $15,000 – $45,000 |
| Plumbing | $8,000 – $20,000 |
| Electrical | $5,000 – $15,000 |
| HVAC | $3,000 – $8,000 |
| Interior Finishes | $15,000 – $40,000 |
Quotes for the same ADU commonly vary 20–40% between builders. We pass your request to up to 5 local builders serving Nashville, where we have them — free, no obligation.
Get Nashville builder quotes →Permit fees in Nashville are $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. The review timeline is 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, with 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. Impact fees are No development impact fee appears in the Codes fee schedule, but Metro Water Services charges capacity fees of $1,375 (water) and $2,300 (sewer) per 350-gallon-per-day unit of flow, a stormwater capacity fee of $0.71 per sq ft of new impervious area, and tap fees if the DADU gets its own meter ($500 for a 5/8-inch water tap, $360 for a 6-inch sewer tap) (MWS Development Fee Schedule, Schedule 15.10.110, rev. January 28, 2025). Ask MWS how many units of flow your DADU is assessed. Pre-approved plans: 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).
| 1-Bedroom Rent | $1,600-$1,750/month |
| 2-Bedroom Rent | $1,850-$2,100/month |
| Annual Rental Income (est.) | $20,100/year |
| Payback Period (est.) | 12.4 years |
| Short-Term Rental | 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. |
| Overall ROI Estimate | 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. |
A typical ADU in Nashville generates approximately $20,100 per year in rental income based on average 1-bedroom rents. At an average construction cost of $250,000, the estimated payback period is 12.4 years — before accounting for the resale value the ADU adds, which an appraiser determines from comparable sales in Nashville and varies by market (often less than build cost).
1. Garage conversions save 40-60% vs new construction since the shell already exists. Average cost in Nashville: $70,000-$120,000.
2. Prefab/modular ADUs offer predictable pricing and faster timelines. Average: $200,000-$400,000.
3. Pre-approved plans — available in Nashville, which can save $3,000-$10,000 in design costs and 2-3 months in review time. See which cities offer pre-approved ADU plans.
4. State grants — California's CalHFA ADU grant (up to $40K) is currently paused; check calhfa.ca.gov/adu for status and your state for active programs.
5. Get multiple bids — ADU contractor pricing varies 20-40% for the same project. We recommend getting at least 3 quotes.
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