Bolthole Index

Warren County, Ohio

Building permits, zoning and land rules in Franklin, Ohio

Franklin, Ohio requires building permits for new construction, additions, remodeling and many accessory projects, while the city administers zoning throughout its incorporated territory.12 Warren County provides Franklin's plan review and building inspections under an agreement with the city.1 For land without public sewer, confirm onsite sewage approval with the Warren County Health District before buying or designing a home.

At a glance

Building permits
Required for new construction, additions, remodeling and many accessory projects1
Zoning
City zoning applies throughout incorporated Franklin2
Zoning approval
A certificate of zoning compliance is required for permitted uses that do not require a site plan3
Septic
Ask the Warren County Health District whether an onsite system can serve the parcel4

Who to call

Building permits

City of Franklin Building & Zoning Division

City zoning, zoning certificates, building-permit intake, and project questions

(937) 746-9921

[email protected]

1 Benjamin Franklin Way, Franklin, Ohio 45005

Online permits →

Building permits

Warren County Building & Zoning Department

Plan review and building inspections for the City of Franklin

513-695-1290

406 Justice Drive Lebanon, OH 45036

Septic permits

Warren County Health District - Environmental Health

Questions about onsite sewage treatment systems and private water systems

513-695-1220

416 S. East St. Lebanon, OH 45036

Contact details are copied from each office’s official page and were checked against it on October 9, 2026.

Off-grid gear

Going off-grid in Franklin means bringing your own water and power. The kit we’d start with:

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Do you need a building permit in Franklin, Ohio?

Yes. Franklin requires building permits for new construction, additions, remodeling, garages, decks, pools, rooftop solar and storage structures over 200 square feet, among other projects.1 The City of Franklin accepts the application, and Warren County reviews plans and performs building inspections for the city.15

Ohio requires covered building plans and specifications to be approved before construction begins.6 Building-department fees follow the locally adopted schedule, so use Franklin's current fee schedule rather than a statewide figure.7

Does Franklin have zoning, and what does it mean for a home?

Franklin's Unified Development Ordinance applies across the city's incorporated territory and regulates land use and development standards.2 For a permitted use that does not require a site plan, submit an application for a Certificate of Zoning Compliance and pay the required fee.3

The applicable zoning district matters. In R-1A, the minimum lot area is 15,000 square feet; in R-1B, it is 10,000 square feet.8 Both districts use a 25-foot front setback, a 10-foot one-side and 25-foot total side setback, and a 40-foot rear setback.9 Both districts cap building height at 35 feet.10

Minimum home size also varies by district: 1,800 square feet in R-1A, 1,500 in R-1B, 1,000 in R-2, and 800 in R-3 and R-4.11 Those figures make the zoning map essential for a tiny-home plan; Franklin's rules do not support one citywide minimum size.

Can you add an accessory dwelling unit in Franklin?

Franklin allows a limited in-law suite inside the principal structure, including an attached garage or space above it; a basement qualifies only with separate ingress and egress.12 The suite may be no larger than 816 square feet, the owner must live on site, occupancy is limited to a family member related by blood, marriage or adoption, and the Planning Commission must approve the plans.12

How do septic permits work inside Franklin?

The Warren County Health District enforces onsite sewage-treatment-system rules in Warren County, but we could not confirm from the available city material when an onsite system may be used at an address inside Franklin.4 Ask Environmental Health whether public sewer is available and whether the parcel is eligible for onsite sewage treatment before ordering house plans.

For a qualifying onsite system in Warren County, the process includes a soil evaluation, system design, site review, an installation permit and an operating permit before installation; the installer must arrange inspection before backfilling.13 After approval, the district inspects within one year and every three years thereafter through its operation and maintenance program.14 Only 0.7% of Warren County soils are rated without severe limits for a conventional septic drain field, so feasibility and system cost deserve early attention.15

Building a home in Franklin: what are the steps?

First, identify the parcel's Franklin zoning district and compare the proposed use, lot area, setbacks, height and floor area with that district's standards.16891011 Second, ask the City of Franklin whether the project needs a site plan or a Certificate of Zoning Compliance and submit a complete application with the required fee.3 Third, settle sewer or onsite sewage treatment with the Warren County Health District before finalizing the site plan.4 Fourth, submit the building-permit package through Franklin; Warren County performs plan review and inspections for the city.15

If any part of the site touches an identified special flood hazard area, obtain a Franklin Floodplain Development Permit before construction, grading, filling or other development begins.17

Can you live in an RV or build a tiny home in Franklin?

We could not confirm that Franklin allows an RV to be occupied as a residence on private land, so ask the City Building & Zoning Division before buying a parcel for that use. Ohio's campground rules address licensed campgrounds and do not answer private-lot residential occupancy.

Franklin does not publish one minimum dwelling size for every residential parcel: the minimum depends on the zoning district, ranging from 800 square feet in R-3 and R-4 to 1,800 square feet in R-1A.11 Confirm the parcel's district and whether the proposed tiny home qualifies as the intended dwelling type before purchase.

Watch-outs

  • Do not confuse the City of Franklin in Warren County with Franklin County, Ohio; Franklin city zoning and permit contacts are the authorities named here.1
  • A Franklin zoning certificate does not replace building-plan approval or a building permit.31
  • A floodplain development permit is required before work begins when development is wholly or partly within, or in contact with, an identified special flood hazard area.17
  • We could not confirm private-land RV occupancy, a citywide tiny-home classification, or onsite-sewage eligibility inside Franklin; ask the City Building & Zoning Division and Warren County Environmental Health before relying on any of those uses.118

Sources

  1. City of Franklin Building & Zoning Division (franklinohio.org)
  2. City of Franklin Unified Development Ordinance (Franklin), quoted and re-checked
  3. City of Franklin Unified Development Ordinance — Certificates of Zoning Compliance (Franklin), quoted and re-checked
  4. Sewage Treatment Systems, quoted and re-checked
  5. Warren County Building & Zoning Department (warrencountyohio.gov)
  6. Section 3791.04 | Submission of plan - approvals - prohibition - fine (Ohio statewide rule), quoted and re-checked
  7. Chapter 4101:7-7 | Fees (Ohio statewide rule), quoted and re-checked
  8. City of Franklin Unified Development Ordinance — Residential Dimensional Standards (Franklin), quoted and re-checked
  9. City of Franklin Unified Development Ordinance — Residential Dimensional Standards (Franklin), quoted and re-checked
  10. City of Franklin Unified Development Ordinance — Residential Dimensional Standards (Franklin), quoted and re-checked
  11. Part Eleven — Unified Development Ordinance (Franklin), quoted and re-checked
  12. City of Franklin Unified Development Ordinance — Accessory Dwelling Units (Franklin), quoted and re-checked
  13. Sewage Treatment Systems, quoted and re-checked
  14. Sewage Treatment Systems, quoted and re-checked
  15. Share of soils USDA rates "not limited" for a conventional septic drain field (SSURGO). A strict rating: the median county is about 6% and a tenth of counties are 0%, so a low figure means most lots need a site evaluation or an engineered system, not that septic is impossible. Cite it only with that caveat: Bolthole Index county data
  16. City of Franklin Unified Development Ordinance — Districts and Land Use Standards (Franklin), quoted and re-checked
  17. City of Franklin Unified Development Ordinance — Floodplain Overlay District (Franklin), quoted and re-checked
  18. Warren County Health District - Environmental Health (warrencohealthoh.gov)

Written October 9, 2026 from the rules quoted below, each taken from an official source and re-checked by an independent reviewer. This is research, not legal advice: rules change, so confirm with the office before you buy or build.

Answers from the rulebook for Franklin

Franklin’s own rules

  • Local zoningPresent (with conditions)

    All incorporated territory of Franklin city, Ohio.

    • The UDO establishes districts and regulates land use, height, area, mass, and development standards.
    “The provisions of this UDO shall apply to all of the incorporated territory of the City of Franklin, Ohio.”
  • Zoning districtsPublished (with conditions)

    All incorporated territory of Franklin city.

    • The published district list includes A-1, PAR, R-1 through R-4, commercial, downtown, office, industrial, and overlay districts.
    “The City is divided into the following zoning districts, which shall be governed by all the use and area requirements of this Ordinance.”
  • Minimum dwelling sizeDistrict specific (with conditions)

    Residential development inside Franklin city in the R-1A, R-1B, R-2, R-3, and R-4 zoning districts.

    • The Official Zoning Map determines the applicable district.
    • The minimum floor-area figures are district-specific requirements under Table 1107.14-1.

    R-1A minimum floor area: >= 1800 sq. ft. · R-1B minimum floor area: >= 1500 sq. ft. · R-2 minimum floor area: >= 1000 sq. ft. · R-3 minimum floor area: >= 800 sq. ft. · R-4 minimum floor area: >= 800 sq. ft.

    “TABLE 1107.14-1: Residential Districts Dimensional Standards | R-1A | R-1B | R-2 | R-3 | R-4 [...] Minimum Floor Area | 1,800 sq. ft. | 1,500 sq. ft. | 1,000 sq. ft. | 800 sq. ft. | 800 sq. ft.”
    One more reviewed finding on this topic
    • District specific (with conditions) — Single-family dwellings in Franklin city's R-1B residential zoning district.
      “TABLE 1107.14-1: Residential Districts Dimensional Standards | R-1A | R-1B | R-2 | R-3 | R-4 [...] Minimum Floor Area | 1,800 sq. ft. | 1,500 sq. ft. | 1,000 sq. ft. | 800 sq. ft. | 800 sq. ft.”
  • Accessory dwellingsLimited

    Accessory dwelling units inside Franklin city.

    • The unit must be in the principal structure; a basement is allowed only with separate ingress and egress.
    • Maximum in-law-suite size is 816 square feet.
    • The owner must live on site, and occupancy is limited to a family member related by blood, marriage, or adoption.
    • Plans require Planning Commission approval and the unit must meet the current Ohio Building Code.

    maximum in-law-suite size: <= 816 square feet

    “Accessory dwelling units must be located in the principal structure, which includes attached garages or areas over attached garages, and shall only include basements when such basements have their own, separate ingress and egress.”
  • Subdividing landRegulated (with conditions)

    Major subdivisions within Franklin city limits.

    • Major subdivisions are subject to Sections 1111.02 through 1111.06.
    • Subdivision procedures, required submittals, Planning Commission review, Council review, and review standards are governed by Sections 1115.06 and 1115.07.
    • Major and minor subdivision fees are provided in Section 1105.09.
    • The applicant must reimburse the City for the actual cost of outside professional review when required by the nature of the proposed subdivision.
    “Applicability: All subdivisions defined as Major Subdivisions shall be subject to the requirements of sections 1111.02, 1111.03, 1111.04, 1111.05 and 1111.06. 5. Procedure: The procedures for the subdivision process, including required submittals, review by Planning Commission and Council, and the applicable review standards are outlined in section 1115.06 for Major Subdivisions and section 1115.07 for Minor Subdivisions.”
  • Building in a floodplainRequired

    Construction or development wholly within, partially within, or in contact with an identified special flood hazard area inside Franklin city.

    • A permit is required before construction or development begins.
    • Maintenance such as roofing, painting, and basement sealing, and small nonstructural activities other than filling/grading valued below $2,500, are exempt from filing.
    • The permit is conditional on work beginning within 180 days and expires after 180 days unless activity has substantially begun and continues to completion.
    • The applicant must obtain other federal, state, or local approvals required before issuance.

    permit commencement period: <= 180 days (Work must commence within this period) · small nonstructural exemption threshold: < 2500 USD (Does not include filling or grading)

    “It shall be unlawful for any person to begin construction or other development activity including, but not limited to filling; grading; construction; alteration, remodeling, or expanding any structure; or alteration of any watercourse wholly within, partially within or in contact with any identified special flood hazard area, as established by the City's Floodplain Map, until a Floodplain Development Permit is obtained from the Floodplain Administrator.”
  • Permit feesVariable (with conditions)

    Subdivision applications inside Franklin city.

    • Major and minor subdivision fees are supplied through UDO §1105.09.
    • The applicant must reimburse actual outside-professional review costs when the City must hire outside professionals.
    “Fees for Major Subdivisions and Minor Subdivisions shall be as provided for in section 1105.09. If, due to nature of the proposed subdivision, it becomes necessary for the City to hire outside professionals to review the proposed subdivision, the applicant, by submitting a subdivision application, agrees to reimburse the City for the actual cost of said outside review.”
  • Permit processPublished (with conditions)

    Zoning-compliance applications and UDO-regulated development inside Franklin city.

    • For a permitted UDO use without a site-plan requirement, an application and the required fee are required.
    • Only complete applications are processed by the City.
    • The UDO has separate listed procedures for major and minor subdivisions.
    “For any permitted use under this UDO for which a Site Plan is not required, an application for a Certificate of Zoning Compliance shall be submitted in accordance with this paragraph and the required fee paid.”

Rules another office applies inside Franklin

Franklin does not set these itself; the county, a health district or the state does, and they apply to every address inside its limits.

  • Minimum lot sizeSpecified

    Single-family R-1 residential subdistricts in Franklin: R-1A and R-1B.

    • Standards are district-specific.

    minimum lot area R-1A: >= 15000 square feet · minimum lot area R-1B: >= 10000 square feet

    “TABLE 1107.14-1: Residential Districts Dimensional Standards | R-1A | R-1B | R-2 | R-3 | R-4 Minimum Lot Area | 15,000 sq. ft. | 10,000 sq. ft. | 6,000 sq. ft. | 4,000 sq. ft. | 10,000 sq. ft.”
  • SetbacksSpecified

    Single-family R-1 residential subdistricts in Franklin: R-1A and R-1B.

    • Both R-1A and R-1B have a 25-foot front setback, 10-foot one-side/25-foot total side setback, and 40-foot rear setback.

    front setback: >= 25 feet (R-1A and R-1B) · side setback, one side/total: 10/25 feet (R-1A and R-1B) · rear setback: >= 40 feet (R-1A and R-1B)

    “Minimum Front Yard Setback | 25 feet | 25 feet | 25 feet | 15 feet | 25 feet Minimum Side Yard Setback (one side/total) | 10/25 feet | 10/25 feet | 6/15 feet | 4/10 feet | 10/25 feet Minimum Rear Yard Setback | 40 feet | 40 feet | 30 feet | 20 feet | 40 feet”
  • Building heightSpecified

    Single-family R-1 residential subdistricts in Franklin: R-1A and R-1B.

    • Standards are district-specific.

    maximum height: <= 35 feet (R-1A and R-1B)

    “Maximum Height | 35 feet | 35 feet | 35 feet | 35 feet | 55 feet”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Franklin or Warren County directly.

  • Building permit — Residential building work inside Franklin city.
  • Owner-builder exemption — Owner-built residences inside Franklin city.
  • Building code adopted — Building construction inside Franklin city.
  • Inspections — Residential building work inside Franklin city.
  • Certificate of occupancy — Occupancy of residential structures inside Franklin city.
13 more unanswered
  • Lot coverage
  • Living in an RV
  • Camping on your land
  • Tiny homes
  • Manufactured homes
  • Who permits septic
  • Septic permit
  • Septic inspection
  • Off-grid sanitation
  • Well permit
  • Mandatory utility hookup
  • Agricultural exemption
  • Short-term rentals

Each answer was extracted from an official source and independently re-checked against that source by a second reviewer. That is an evidence check, not legal advice. Rules change; confirm with the authority before you buy or build.

Unanswered questions are usually a sign that Franklin publishes no rule on the point, not that none exists. Warren County’s page lists the county offices to call.

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