ADU Pass
Franklin
No County portion
Also in: Simpson County · Warren County
ADU Pass helps homeowners in Franklin, No County, Kentucky navigate the permit paperwork for building an accessory dwelling unit. This area covers 1 ZIP code.
Map
ADU details
ADU legality: with-restrictions
An ADU in Franklin is technically a Conditional Use Permit for an accessory or two-family residence under the joint zoning manual, not a defined ADU class. Expect a planning-commission public hearing (~6 weeks lead time), a CUP fee, and standard county building-permit review. This is a cross-listing stub - the authoritative file is at kentucky/simpson-county/franklin.json.
Cost scenarios
| Scenario | Sq ft | Permit | Build | Total |
|---|---|---|---|---|
| minimum | 400 | $1,850 | $76,000 | $77,850 |
| 600 | 600 | $2,250 | $114,000 | $116,250 |
| midpoint | 800 | $2,600 | $152,000 | $154,600 |
| maximum | 1,200 | $3,400 | $240,000 | $243,400 |
Fee breakdown (as of 2026-04)
Permitting process
- Pre-application meeting at Franklin-Simpson Joint Planning (~7d)
Schedule a free pre-app at 117 W. Cedar St. (City) or 100 Courthouse Sq (County) to confirm zoning district (R-1, R-2, R-3, A-1) and applicable lot/setback/parking standards from the joint manual. - File Conditional Use Permit application (~14d)
Submit CUP application with site plan, floor plan, elevations, and CUP-fee check to City Hall (Zoning@franklinky.org). The CUP runs to the planning commission's monthly meeting. - Public notice + neighbor mailing (~10d)
Joint planning office mails notice to property owners within statutory radius and publishes in The Franklin Favorite ~10 days before hearing. - Planning Commission public hearing (~1d)
Monthly meeting (typically third Tuesday). Commission decides CUP grant / conditions / denial. - Building permit application to Kentucky DHBC field office (~7d)
After CUP approval, submit residential construction application to KY DHBC; CUP letter is part of the package. - DHBC plan review (~21d)
State plan reviewer issues approval or comment letter; backlog 2-4 weeks. - Construction inspections + final / CO (~7d)
DHBC field inspector handles the foundation/framing/MEP/insulation/final cycle. Joint planning issues a separate zoning compliance letter at completion.
Viability (permitted uses)
- Long-term rental: yes (Permitted as accessory residence under CUP) Long-term rental of a CUP-approved accessory residence is the dominant pattern.
- Short-term rental: with-restrictions (Joint zoning manual STR / tourist-home provisions) STR (Airbnb / VRBO) treated as a tourist home / B&B use under the joint manual; CUP required in residential zones. City of Franklin requires occupational license + transient-room tax registration.
- Office rental: no Joint manual restricts ADU / accessory residence to dwelling use; commercial office tenancy not permitted in residential zones.
- Home office: yes Home occupation explicitly allowed in residential zones with limits on signage, employees, and traffic.
- Studio / workshop: yes Owner / family use is unrestricted.
- Agriculture: with-restrictions (A-1 Agricultural district) Farmhand / caretaker accessory residence is one of the recognized CUP cases on A-1 parcels in Simpson County.
- Relative support: yes Family-occupancy ADU is the most common CUP basis - aging-in-place / multigenerational housing.
Incentives
- KHC Welcome Home Grant — Up to $10,000 toward down payment / closing (First-time-homebuyer income limits; Simpson County eligible)
- Franklin Industrial / Housing Authority programs — Franklin-Simpson Industrial Authority and the local housing nonprofit occasionally bundle infrastructure assistance for small-scale infill.
Contacts
Staff: City of Franklin Planning Office (Permit / CUP intake), Simpson County Planning & Zoning (County-side intake (100 Courthouse Sq))
Utilities
- Water: City of Franklin Water and Wastewater (TVA-region wholesale) · 21d connect · $700
- Sewer: City of Franklin Wastewater (Big Trammel Creek WWTP) · 21d connect · $800
- Electric: Franklin Electric Plant Board (TVA wholesale) · 14d connect · $650
- Gas: Atmos Energy · 21d connect · $1,100
Property values & taxes
Market rent by ADU size
| Sq ft | Rent |
|---|---|
| 400 | $850/mo |
| 600 | $1,050/mo |
| 800 | $1,275/mo |
| 1,200 | $1,650/mo |
Construction timeline
Realistic total: best 7mo · typical 11mo · worst 17mo
Nashville-area GC backlog crosses the state line into Simpson County, lengthening lead times relative to Hickman / Carlisle.
Modular pathway Kentucky DHBC Manufactured/Modular Housing Program · inspectors are regular with modular · 2 modular permits (last 24mo)
I-65 access is excellent; oversize-load route through Clayton's Westmoreland and Rutledge factories runs straight up I-65.
Financing
State ADU loans:
- KHC First Mortgage Programs (Kentucky Housing Corporation)
- KHC Down Payment Assistance Program (DAP) (Kentucky Housing Corporation) up to $12,500
- USDA Rural Development Section 502 (Simpson County eligible outside city limits) (USDA RD Kentucky)
Insurance impact
Hail / wind exposure on the southern Kentucky border modestly above Hickman; karst sinkhole rider available as extra coverage in Simpson County.
HOA prevalence & preemption
Newer subdivisions on the north side of Franklin (toward I-65) carry HOAs; older town blocks do not. Kentucky has no HOA-ADU preemption.
Regulatory overlays (2)
- other — Karst / sinkhole exposure: Simpson County sits on the western edge of the central-Kentucky karst belt; sinkhole-formation potential is real on parcels south and east of Franklin. · +7d · +4% cost
DHBC may require a soils / karst report for foundations larger than typical residential; Appendix Q tiny dwellings on pier foundations skirt this. (map) - flood-zone — FEMA Zone A on Big Trammel Creek and Drake Creek; small portions of Franklin south side cross the floodway. · +10d · +6% cost
Lowest finished floor 1 ft above BFE; flood vents on enclosed below-base areas. (map)
Technical envelope (climate & building code)
Climate & energy code
Building code
Amendments:
- Kentucky deletion of IRC R313 sprinkler mandate — KY does not require residential fire sprinklers.
- Joint Franklin-Simpson zoning amendments to lot/setback standards — Local zoning sets setbacks and lot coverage; building code is the state KRC.
Contractor market (aggregate)
Legal history (timeline)
Current ordinance: Joint Zoning Regulations Manual for the City of Franklin and Simpson County, Kentucky, adopted 1972-01-01, last amended 2026-01-15
- 1972-01-01 — Franklin-Simpson Joint Planning Commission established (city-ordinance)
City of Franklin and Simpson County formed a joint planning unit under KRS 100, allowing one regulation manual to govern both jurisdictions.
Effect: Single shared zoning code applies inside and outside Franklin city limits. - 2022-01-15 — Joint Zoning Regulations Manual - 2022 reissue (city-ordinance)
Republished comprehensive zoning manual for City of Franklin and Simpson County.
Effect: Maintained CUP framework for accessory residences; no by-right ADU class added. - 2025-02-25 — Kentucky HB 576 (2025) - statewide ADU enabling bill (stalled) (state-law)
Would have required local governments to allow at least one ADU on every residential lot.
Effect: Did not pass; Franklin retains discretionary CUP framework. - 2026-01-15 — Joint Zoning Regulations Manual - 2026-01 update (city-ordinance)
Most recent posted update to the Franklin-Simpson zoning manual.
Effect: Refreshes definitions, plan-review fees, and references to current Kentucky Residential Code; ADU treatment unchanged.
Known issues (1)
- regulatory-gap (since ongoing) — Every ADU runs as a Conditional Use Permit, which adds 4-6 weeks vs. by-right. (source)
County: no attribution (synthetic bucket)
No county
This city sits in the state's "no county" bucket — its ADU rules derive directly from state law and city ordinance without a county intermediary. No county-level sections apply.
Kentucky state — ADU law and programs
State financing programs
Kentucky does not operate an ADU-specific statewide loan, grant, or forgivable-loan program. The Kentucky Housing Corporation (KHC) is the state housing finance agency and administers first-time-homebuyer mortgage products, the Welcome Home Grant (down-payment assistance), the KHC Down Payment Assistance Program (up to $12,500 second mortgage), and Mortgage Credit Certificates. None target ADU construction directly. ADU costs may be financed through standard renovation or construction-loan products under KHC programs when the ADU is part of a qualifying primary-residence transaction.
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.
ZIP Code
- 42135
Post Office
- 619 N Main St, 42134