ADU Rulebook

City · Tennessee

ADU rules in Chattanooga

4 sources

These are the primary sources for accessory dwelling unit regulations in Chattanooga: the city's own zoning code, planning department pages, and permit guides. Start here before talking to anyone: the rules below are what your permit reviewer will apply.

Rules at a glance

Detached (backyard) ADU
Allowed

Detached ADUs are a permitted accessory use to single-unit detached dwellings in the zones marked P in the use matrix. Must be located in the rear or interior side yard only, never the front yard; max height 24 feet (two stories allowed only if the principal dwelling is more than one story).

Chattanooga Zoning Ordinance Sec. 38-43(b)(1), (4), (6), (11); Table 38-41.1
Attached or internal ADU
Allowed

Attached ADUs are permitted in the same zones; limited to the zone's maximum height, cannot exceed the height of the principal dwelling, and must meet the principal-structure setbacks. Separate entrance must be on the side or rear (front entrance only if shared with the principal dwelling, or if the door existed before May 31, 2022).

Chattanooga Zoning Ordinance Sec. 38-43(b)(5), (7), (12), (15)(v); Table 38-41.1
Maximum size
800 sq ft gross (detached and attached alike), measured by exterior dimensions; conditioned sleeping lofts and interior stairwells count toward the cap. Conversions of existing space must also meet the 800 sq ft standard.

The 700 sq ft cap from the 2022 ordinance (No. 13839) is superseded; the current code allows 800 sq ft.

Chattanooga Zoning Ordinance Sec. 38-43(b)(8), (9), (10)
Owner occupancy
Not required

No owner-occupancy requirement appears anywhere in the ADU standards. The code does require common ownership: the ADU must be owned by the same owner(s) as the principal dwelling and can never be subdivided, condo-ized, or separated onto its own lot. (Owner occupancy does matter for short-term rental use: only homestay STVRs, the operator's primary residence, are allowed in residential zones.)

Chattanooga Zoning Ordinance Sec. 38-43(b)(3); Secs. 38-85, 38-86
Extra parking
No. There is no minimum on-site parking requirement for ADUs; existing required parking for the principal dwelling must be maintained or replaced on-site if it is lost when the ADU is created.Chattanooga Zoning Ordinance Sec. 38-43(b)(13)
Approval process
Permitted use

ADU is a by-right permitted accessory use (P, no special exception) in Table 38-41.1 for the zones RN-1-6, RN-1-5, RN-1-7.5, RN-2, RN-3, TRN-1, TRN-2, TRN-3, C-NT, and A-1; a residential building permit through the Land Development Office is still required to construct one.

Chattanooga Zoning Ordinance Sec. 38-41, Table 38-41.1 (ADU row); Sec. 38-43(b)
Rental restrictions
Long-term rental of an ADU is not restricted by the ADU standards (no minimum lease term stated). Short-term vacation rental of an ADU is allowed only as a homestay STVR (the property must be the operator's primary residence at least 183 days a year) within the STVR overlay district, with a certificate required; a lot may operate an STVR in the principal dwelling or the ADU, but not both. Absentee (non-owner-occupied) STVRs are confined to mixed-use and commercial zones that allow hotels.

STVR rules are in Article XVII, adopted with the same 2024 ordinance.

Chattanooga Zoning Ordinance Secs. 38-85 (Homestay definition), 38-86(a), (c), (d), 38-87
The fine print: 7 caveats that can change the picture
  • Chattanooga adopted an entirely new zoning ordinance (Ord. No. 14137, July 23, 2024, effective December 18, 2024) replacing the pre-2025 Chapter 38; the widely cited 2022 ADU ordinance (No. 13839, 700 sq ft cap, R-zone framing) is superseded. Current code raises the cap to 800 sq ft and uses new RN/TRN zone names.
  • Zone-dependent: ADUs are permitted only in RN-1-6, RN-1-5, RN-1-7.5, RN-2, RN-3, TRN-1, TRN-2, TRN-3, C-NT, and A-1. They are NOT listed as an allowed use in RN-1-3, TRN-4, R-MH, most commercial and industrial zones, INST, or OS. The Downtown Form-Based Code area (Article VI) has its own use rules.
  • ADUs are accessory only to single-unit detached dwellings; one ADU per lot, and not in association with townhouses, duplexes, or multi-unit buildings.
  • The ADU must remain in common ownership with the principal dwelling; subdivision, horizontal property regime, or fee-simple condo conversion of the ADU is prohibited.
  • Detached ADUs: rear or interior side yard only, with fixed setbacks (interior side 5 ft, rear 5 ft, alley 5 ft, corner side 10 ft); shipping containers and RVs are prohibited and a permanent foundation is required.
  • ADUs that existed before May 31, 2022 (including in front yards) can be legalized if brought up to building, fire, and municipal codes; the allowance dies if the principal structure is demolished (Sec. 38-43(b)(16)).
  • The ordinance does not override HOA covenants or historic district guidelines.

Summarized from Chattanooga's ordinance text, read July 2026; every row links the code section it came from. Rules often vary by zone and lot, so treat this as orientation, not a permit determination, and confirm with the planning department before you commit to a design.

Compare Chattanooga with 3 nearby cities

ADU regulations

Short-term rental rules

Planning to rent your ADU on Airbnb or VRBO? Chattanooga regulates short-term rentals separately; check these before counting on nightly rental income.

Spotted something outdated?

Zoning codes change. If a link is dead or Chattanooga has updated its ordinance, report it and we'll verify against the official source.

Report a correction

Ready to build?

Planning an ADU in Chattanooga?

Tell us about your project and we'll match you with vetted local designers and builders as we bring them online. No cost, no obligation.

Find a builderEstimate costs first