Rental conversions in Columbus

Columbus Ordinance 2526-2025, passed in November 2025, changed the zoning code to allow accessory dwelling units by right, subject to set conditions, in all residential and apartment residential districts; before that, an ADU needed a Council variance.³ ADUs are allowed in Columbus residential, apartment residential and mixed-use districts, but not in a Planned Community or Planned Unit Development district.¹¹

Columbus recognizes attached ADUs with their own entrance, detached ADUs that stand alone or sit above or beside a garage, and internal ADUs built entirely inside an existing building, such as a converted basement or attic.¹¹ Columbus's ADU handbook says an ADU may be up to 1,000 square feet or 65% of the main building's net floor area, whichever is greater, must be smaller than the main house, and can be no taller than 25 feet.¹¹ Columbus requires no additional parking for an ADU, although the main house still has to keep its own required parking on the lot.¹¹

Columbus recommends an optional preliminary zoning review for an ADU, which tells the owner whether the plan will need any variances from the Board of Zoning Adjustment before a building permit is sought.¹¹ A Columbus ADU must have a kitchen, living and sleeping areas, sanitation and permanent utility connections, and the city reviews sewer, water and electrical capacity during permitting.¹¹ On a narrow city lot, that early review is the cheapest way to learn whether side yards, rear-yard coverage or a sewer connection will cause trouble before you pay for drawings.

Converting a single-family house into a two-family is a different path from adding an ADU. Columbus requires a building permit with plan review for any planned work, whether new construction, an alteration to an existing building or space, or a change in occupancy.¹² In Columbus, a Certificate of Occupancy is the final document issued when a use is established or changed, showing that the structure has passed every inspection required to occupy it legally and setting the conditions for its use.¹²

The Residential Code of Ohio, based on the 2018 International Residential Code, applies to the construction, alteration, replacement and repair of every one-, two- or three-family dwelling in the state.¹³ The Residential Code of Ohio requires the units of a two-family dwelling to be separated by wall and floor assemblies with at least a 1-hour fire-resistance rating, or a 1/2-hour rating in a building with a full sprinkler system.¹⁴ In an older house, that often means a new rated floor and ceiling between the units and closing off an interior stair.

Zoning still decides whether a second unit is allowed on the lot, so check the district on the city's zoning map before you design anything. Columbus lets a homeowner work on their own single-family home with help only from immediate family, as long as the home is not part of a multiple-occupancy dwelling and is occupied, or meant to be occupied, by the owner's family.¹² Once the building holds two households, plan on hiring registered contractors for the work.

Under Chapter 4515 of the Columbus City Codes, enacted in April 2026, the owner or local operator of any residential rental property in the city must register it with the city each calendar year; the registry starts with 2027, and initial registration runs from October 1 through December 31, 2026.¹⁵ Every three years, each registered Columbus rental property gets a Preventative Education Inspection of its exterior, common areas and shared building systems; individual units are not inspected inside unless, for example, the tenant asks.¹⁵

The county keeps its own list as well. Under Ohio Revised Code 5323.02, the owner of residential rental property in Franklin County must file contact information with the County Auditor within 60 days of a transfer or of any change, and a property that isn't registered can be fined $150 per tax year.¹⁶

Short-term renting follows a separate track. A Columbus ADU may be rented long or short term, but a short-term rental needs a permit under City Code Chapter 598, and rentals fall under the rental registry in Chapter 4515.¹¹ Columbus licenses short-term rentals under City Code Chapter 598; the city's 2026 application lists a $20 application fee, a $75 license for a primary residence and $150 for a non-primary residence, plus a BCI background check and a 24-hour local contact.¹⁷ On a Columbus short-term rental license, the bedrooms listed can't exceed what the Franklin County Auditor's website shows, and the maximum occupancy can't exceed three times the number of bedrooms.¹⁷

A landlord who does renovation work on pre-1978 rental housing personally needs both EPA firm and renovator certification; a landlord who hires the work out needs neither, but the firm must be Lead-Safe Certified.¹⁸ Before a renter signs a lease for most pre-1978 housing, federal law requires the landlord to disclose known lead-based paint and hazards, share available records, hand over EPA's Protect Your Family From Lead pamphlet and include a Lead Warning Statement.¹⁹

Inside city limits there may be money for the lead work. Lead Safe Columbus, a HUD-funded city program that says it is accepting applications, can pay for lead hazard control, healthy-home repairs and radon testing and mitigation in single- and multi-family homes built before 1978 inside city limits, including tenant-occupied or vacant rentals; occupied units must be at or below 80% of area median income, and owners agree to a three-year restrictive covenant.²⁰

The Residential Code of Ohio requires every sleeping room, including one in a basement, to have at least one operable emergency escape and rescue opening, unless the home has an automatic sprinkler system and the basement has the means of egress the code spells out.¹⁴ Ask the company to show on the plans how each bedroom in the new unit meets that rule, and where the smoke and carbon monoxide alarms will go.

The background to Columbus's ADU ordinance says ADUs give families a way to house aging parents or adult children and can add a source of income that supports housing stability.³ More than one in four adults 65 and older fall each year.²¹

For a parent, a one-level cottage or an attached unit at grade works far better than an apartment up a garage stair or down in a basement. Ask for a curbless shower, a wide entry door, lighting along the walk from the main house and a bedroom close to the bath, and ask whether the company has done aging-in-place work. NAHB's Certified Aging-in-Place Specialist (CAPS) credential trains remodelers in home modifications for aging in place.²²

When you call the number on this page, the recorded call goes to one independent company that handles rental conversions in the Columbus area. You talk through the unit, the construction and the price with them directly.

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Before you sign a contract, look the company up yourself. Columbus requires every contractor working in the city to hold the right city license or registration before applying for permits, and contractors in the five OCILB trades must hold the State of Ohio license first.²³ Check an Ohio license