ADU Pass
Franklin
Warren County portion
Also in: No County · Simpson County
ADU Pass helps homeowners in Franklin, Warren 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
Same controlling code as the no_county/franklin and (canonical) simpson-county/franklin files: Franklin-Simpson joint zoning manual, CUP-driven ADU pathway, Kentucky DHBC residential building permit. The Warren County slug is wrong - leaving this stub in place documents the slug collision rather than implying a separate ruleset.
Cost scenarios
| Scenario | Sq ft | Permit | Build | Total |
|---|---|---|---|---|
| minimum | 400 | $1,900 | $76,000 | $77,900 |
| 600 | 600 | $2,300 | $114,000 | $116,300 |
| midpoint | 800 | $2,700 | $152,000 | $154,700 |
| maximum | 1,200 | $3,500 | $240,000 | $243,500 |
Fee breakdown (as of 2026-04)
Permitting process
- Reject Warren County intake; route to Franklin-Simpson (~1d)
Confirm with Warren County City-County Planning Commission (Bowling Green) that the parcel is in Franklin / Simpson and outside their jurisdiction. They will redirect to Franklin-Simpson Joint Planning at +1-270-596-2756. - Pre-application meeting at Franklin-Simpson Joint Planning (~7d)
Schedule pre-app at 117 W. Cedar St. (City) or 100 Courthouse Sq (County). Confirm zoning district 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). - 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. - Building permit application to KY DHBC (~7d)
After CUP approval, submit residential construction application to Kentucky 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 foundation/framing/MEP/insulation/final. 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.
- Office rental: no Joint manual restricts ADU / accessory residence to dwelling use.
- Home office: yes Home occupation explicitly allowed in residential zones.
- 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.
- Relative support: yes Family-occupancy ADU is the most common CUP basis.
Incentives
- KHC Welcome Home Grant — Up to $10,000 toward down payment / closing (First-time-homebuyer income limits)
- Franklin Industrial / Housing Authority programs — Local industrial / housing authority occasionally bundles 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)), Warren County City-County Planning Commission (informational only) (Bowling Green / Warren only - not Franklin)
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
Bowling Green / Warren GC backlog feeds into Simpson; lead times marginally longer than deeper-rural KY.
Modular pathway Kentucky DHBC Manufactured/Modular Housing Program · inspectors are regular with modular · 2 modular permits (last 24mo)
I-65 access excellent; oversize-load route runs straight up I-65 from Tennessee modular plants.
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; karst sinkhole rider available.
HOA prevalence & preemption
Newer subdivisions on the north side of Franklin (toward I-65 / Warren line) 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
Note: Warren County to the north sits on even deeper karst (Mammoth Cave / Lost River system) - if parcel were actually in Warren rather than Simpson, karst impact would be larger. (map) - flood-zone — FEMA Zone A on Big Trammel Creek and Drake Creek (Simpson side); on the Warren side, Barren River / Drakes Creek are the controlling streams (not relevant to Franklin city). · +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; 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 (controlling), adopted 1972-01-01, last amended 2026-01-15
- 1972-01-01 — Franklin-Simpson Joint Planning Commission established (canonical timeline) (city-ordinance)
Franklin and Simpson County formed a joint planning unit under KRS 100.
Effect: Single shared zoning code applies inside and outside Franklin city limits - and explicitly excludes Warren County. - 1990-01-01 — Warren County City-County Planning Commission rebuilt around Bowling Green / unincorporated Warren (city-ordinance)
Warren's planning unit covers Bowling Green and unincorporated Warren - not Franklin (Simpson seat).
Effect: Confirms jurisdictional separation; Franklin remains under Simpson rules. - 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 (canonical for Franklin) (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 (2)
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
- 42170
Post Office
- 619 N Main St, 42134