How Much Does an ADU Cost in Tennessee in 2026?
ADU costs in Tennessee range from $65,000 for a basic garage conversion in Memphis to $298,000+ for a high-end detached DADU in Brentwood. The most common Nashville build — a 600 sq ft detached mid-range unit — costs $140,000 to $195,000.
Tennessee is one of the best-value ADU markets in the Southeast. Nashville's landmark BL2025-1007 reform (late 2025) opened by-right DADU permitting across most of the city. Tennessee has no state income tax — all rental income is taxed federally only. The key Nashville caveat: new DADUs built under the reform on RS-zoned lots cannot be used for short-term rental.
Tennessee ADU Cost by City (600 sq ft Mid-Range Detached, 2026)
Franklin and Brentwood command the highest rents in the state. Memphis has the lowest build costs but also lowest rents and a 10,000 sq ft minimum lot requirement.
| City | Basic | Mid-Range | High-End | Permit Est. | Avg Rent |
|---|---|---|---|---|---|
| Franklin / Brentwood | $110K | $195K | $298K | $3,000 | $1,850/mo |
| Nashville (Davidson Co.) | $100K | $185K | $275K | $2,500 | $1,750/mo |
| Murfreesboro | $88K | $162K | $248K | $2,000 | $1,500/mo |
| Chattanooga | $78K | $145K | $225K | $1,800 | $1,350/mo |
| Knoxville | $75K | $140K | $218K | $1,800 | $1,300/mo |
| Clarksville | $72K | $135K | $208K | $1,600 | $1,250/mo |
| Memphis | $65K | $122K | $188K | $1,500 | $1,150/mo |
| Johnson City / Tri-Cities | $68K | $128K | $195K | $1,500 | $1,200/mo |
Memphis lot minimum 10,000 sq ft applies before any build. Nashville figures reflect 2026 BL2025-1007 by-right zones. Based on 2026 Tennessee market data.
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Tennessee ADU Rules — Nashville Reform and Key Facts
Landmark Nashville reform (late 2025). DADUs now by-right in most residential zones within the Urban Services District. No more overlay district required. Alley access requirement removed. Lot <10K sq ft: max 850 sq ft. Lot ≥10K sq ft: max 1,200 sq ft.
Tennessee has no state income tax on wages or rental income (Hall Tax eliminated 2022). All ADU rental income is taxed at the federal level only — the same no-income-tax advantage as Nevada and Florida.
Tennessee is one of few states where some counties (including portions of rural Middle and East Tennessee) have no zoning code. In unzoned counties, ADU construction is governed by building codes only — no zoning review.
Knoxville permits one ADU per single-family lot up to 1,200 sq ft or 40% of main dwelling. Owner-occupancy required in either the main home or ADU. Internal, attached, and detached all permitted.
Critical: Nashville BL2025-1007 prohibits short-term rental (Airbnb/VRBO) in any DADU built under the new by-right provisions on RS (single-family) lots. If STR income is your goal, verify your zoning district (R vs RS) before breaking ground.
Tennessee has no statewide ADU law. Rules are set city and county level. What is permitted in Nashville may not apply in Shelby County. Verify with your local planning department before design spend.
Memphis requires a minimum lot size of 10,000 sq ft for ADU construction. Lots between 10,000 sq ft and 1.5 acres may build an ADU up to 700 sq ft. Smaller urban lots in Memphis are ineligible.
Existing Nashville STR licenses do not automatically apply to a new DADU. Short-term rental permits are issued per-property and subject to availability. Owner-occupied STR requires primary residency at the property.
Tennessee ADU Zoning — City by City
Nashville's landmark 2025 reform (BL2025-1007) opened DADUs to by-right permitting across most of the Urban Services District — no more overlay requirement, no alley access required. Lot size governs maximum ADU size: under 10,000 sq ft allows 850 sq ft; 10,000 sq ft or larger allows 1,200 sq ft. Critical caveat: new DADUs on RS-zoned lots cannot be used as STRs. Verify your zone (R vs RS) before design. Permit timeline 6–10 weeks.
Franklin and Brentwood command the highest ADU rents in Tennessee ($1,700–$2,200/mo) due to affluent demographics and corporate relocation demand. Williamson County has separate ADU rules from Nashville — verify with Williamson County Planning before assuming Nashville rules apply. Strong demand from healthcare and tech sector workers.
Knoxville allows ADUs on any single-family lot — internal, attached, or detached — up to 1,200 sq ft or 40% of the main dwelling. Owner-occupancy required in either unit. ADU cannot be visible from the street view. Permit timeline 6–8 weeks. University of Tennessee drives strong student and faculty rental demand.
Memphis requires a minimum 10,000 sq ft lot for ADU eligibility — eliminating many smaller urban infill lots. Qualifying lots (10,000 sq ft to 1.5 acres) may build up to 700 sq ft. Permit fees among the lowest in Tennessee ($1,200–$1,800). Strong rental demand from University of Memphis and medical district workforce.
Tennessee vs Georgia ADU — Side-by-Side Comparison
| Metric | Tennessee | Georgia |
|---|---|---|
| Average build cost (600 sq ft) | $120,000–$170,000 | $130,000–$175,000 |
| State ADU law | None — local only | None — local only |
| Nashville vs Atlanta STR rules | Banned in new DADUs | Banned in Atlanta |
| State income tax on rental | None | 5.75% |
| Some counties — no zoning | Yes | No |
| Major city 2025 zoning reform | Nashville BL2025-1007 | None equivalent |
| Average monthly rent (Nashville) | $1,600–$1,900 | $1,300–$1,600 |
| Cash-on-cash ROI (est.) | 9–12% | 8–11% |
Tennessee ADU ROI by City
Assumes 25% expense ratio and 5% vacancy. No state income tax not reflected in gross ROI — improves net returns vs. comparable GA/VA/NC builds. Not a guarantee of returns.
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→Frequently Asked Questions
How much does an ADU cost in Tennessee in 2026?
ADU costs in Tennessee range from $65,000 for a basic garage conversion in Memphis to $298,000+ for a high-end detached unit in Brentwood or Franklin. The most common Nashville build — a 600 sq ft detached mid-range DADU — costs $140,000 to $195,000. Tennessee is 15–25% less expensive than comparable builds in Arizona or Nevada due to lower labor rates and simpler building code requirements.
What is Nashville BL2025-1007 and what changed for ADU owners?
Nashville Metro Council Bill BL2025-1007, passed in late 2025, is the most significant ADU reform in Tennessee history. It allows detached accessory dwelling units (DADUs) by right in most residential zones within Nashville's Urban Services District — eliminating the prior overlay district requirement that blocked most of the city. The alley access requirement was also removed. Maximum sizes increased: 850 sq ft on lots under 10,000 sq ft; 1,200 sq ft on lots of 10,000 sq ft or more.
Can I use my Nashville DADU for Airbnb or short-term rental?
Not if it was built under the new BL2025-1007 by-right provisions on an RS-zoned (single-family) lot. The bill included a trade-off: new DADUs built under base code allowance on RS lots are prohibited from STR use. If short-term rental income is your goal, verify your property's specific zoning designation (R vs RS) with Nashville Metro Codes before finalizing your plans. Properties in R-zoned (one and two family) districts may have different rules.
Does Tennessee have a state income tax on ADU rental income?
No. Tennessee eliminated its Hall Income Tax in 2022 and has no state income tax on wages, salaries, or rental income. All ADU rental income in Tennessee is taxed at the federal level only. This is the same no-income-tax advantage as Nevada and Florida — and a meaningful difference from Georgia (5.75%), North Carolina (4.75%), and Virginia (5.75%).
What is the ROI on an ADU in Nashville in 2026?
A mid-range 600 sq ft DADU in Nashville costs $150,000 to $200,000 all-in and generates $1,500 to $1,900 per month in long-term rental income. Cash-on-cash ROI runs 9–11%, with a payback period of 10–12 years. Franklin and Brentwood offer the highest ROI in the state due to strong rental demand from corporate relocations. Tennessee's no-income-tax advantage improves effective net returns compared to most Southeast competitor states.
What are Tennessee's rules for ADUs in counties with no zoning?
Tennessee is one of a small number of states where certain rural counties have no zoning ordinance. In unzoned Tennessee counties, ADU construction is governed primarily by state and local building codes rather than land use restrictions. This means detached ADUs may be permitted without the standard setback, size, and design review requirements that apply in zoned municipalities. Contact your county building department directly — rules vary and some counties that previously had no zoning have adopted codes in recent years.
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