Accessory Dwelling Units
Background
Accessory Dwelling Units (ADUs) are secondary housing units on the same lot as a primary, single-family residence. Think of a converted space above a garage, an apartment in the basement or attic of a home, or a small detached “mother-in-law suite” in a backyard—these are all ADUs.
On June 26, 2023, Cincinnati City Council passed Ordinance 0266-2023, which modified the City Zoning Code to legalize ADUs and define various rules, regulations, and restrictions. The ordinance became effective on October 2, 2023. If you live in a single-family dwelling, you can build or convert existing space into an ADU on your property, as long as you permit and register the ADU according to the rules in the Zoning Code.
View the ADU Ordinance Learn more about how we got here
Want to get started? View the ADU flowchart with a step-by-step look at the entire process. For more detailed information, read the specific sections below or the ADU FAQ at the bottom of this page.
Regulations
All ADUs are governed by the ADU regulations outlined in Chapter 1421-06 of the Zoning Code. These regulations are in addition to existing building code regulations. This code regulates height, setback, lot coverage, entrance, size, parking, occupancy, and more. Additional zoning regulations also apply.
To learn more about specific regulations for your property, please contact the Zoning Division at (513) 352-2430 or zoninginfo@cincinnati-oh.gov.
New Construction - Building Permits
To begin construction of an ADU, permits must be issued by the Department of Buildings and Inspections. To receive a permit, all code requirements must be met, including building code regulations, zoning code regulations, and any other applicable regulations. Please see the Buildings and Inspections website for more information about permits, or call the permits office at (513) 352-3271 with any questions.
Buildings and Inspections Permit Guide
Registration
All ADUs in the City of Cincinnati must be registered with the Zoning Administrator. To register a new ADU, renew an existing registration, or update an existing registration, please log in through the portal below, register, and follow the steps of the online process.
ADU Registration Portal ADU Owner Acknowledgement Form
Occupancy and Covenant
The property owner or a designated responsible person is required to reside in either the primary residence or ADU. Property owners must submit a restrictive covenant on any property with an ADU, which must be approved by the City Solicitor and recorded with the Hamilton County Auditor.
Please use the draft covenant below and fill in details specific to your property. When the covenant is completed and ready for review, email it to zoningInfo@cincinnati-oh.gov. The City’s Zoning Division and Law staff will review and let you know when it’s ready to sign and submit for recording to the Hamilton County Recorder’s Office. When it’s ready for submission to the County, call the Hamilton County Recorder’s Office at (513) 946-4570.
Draft Covenant for ADU Occupancy
Failure to comply with the owner/responsible person occupancy requirement will result in a Class F Civil Offense, which carries a $15,000 fine.
Rental Operation
ADUs may be operated as a rental unit so long as all other requirements, including the occupancy restrictions, are met. Both residential and short term rentals are permitted, provided that the property owner properly registers the ADU.
Residential Rentals
The department of Buildings and Inspections requires all residential rental units to be registered with the city. Please register at the link below.
Residential Rental Registration Website
Short Term Rentals
All short-term rentals in Cincinnati are required to follow the Short-Term Rental regulations and be registered with the city. See the links below to review the regulations and register.
Short-Term Rental Regulations Short-Term Rental Registration
Frequently Asked Questions
Can an ADU be added to any property?
ADUs are permitted on properties that allow single-family residential use and contain a single-family dwelling. Lots that contain multi-family buildings (including duplexes, triplexes, and small apartment buildings) cannot add ADUs
Does an ADU have to be detached from the single-family residence?
No. While detached ADUs are permitted, an ADU can also be a constructed or converted dwelling that is attached to the primary residence, including an attic or basement apartment, a converted garage, an addition on the back of a house, etc.
Can I convert my attic or basement to an ADU?
An ADU is required to provide a separate exterior entrance, independent of the entrance to the single-family dwelling. If you can provide a separate exterior entrance and can meet all building code requirements to create an ADU in your attic or basement, then yes, this would be permitted.
Can one property have two ADUs? Can one ADU be attached to the primary residence, with a separate detached ADU elsewhere on the property?
No, only one ADU is permitted per lot.
Can I use a recreational vehicle as an ADU on my property?
No, detached ADUs must be of permanent construction.
Do ADUs need their own independent utility service, or can I use the utilities from the primary residence?
This will be assessed by the utility provider on a case-by-case basis.
Does the owner have to occupy the single-family dwelling unit?
The owner must maintain residence in either the single-family dwelling or ADU, or designate a responsible person who maintains residence in the principal single-family dwelling unit or ADU.
What is a “Responsible Person” and how do I designate them?
Responsible Person is defined under §1421-06 (l)(4)(ii) in the Municipal Code. In short, the responsible person has the authority for decision making, management, and financial responsibility for the property. Designation of the responsible person occurs through the registration process.
Can an ADU be rented as a short-term rental, e.g., Airbnb or Vrbo?
Yes. As long as the owner or responsible person occupies one of the dwelling units, short term rentals can be operated in accordance with the provisions of Chapter 856 of the Municipal Code. All short-term rentals in Cincinnati are required to follow the Short-Term Rental Regulations and be registered with the city.
If an existing Accessory Residential Structure does not meet the lot coverage restrictions, setbacks, or height is it permitted to be converted to an ADU?
Yes, as long as the footprint is not being expanded.
Where is the ADU’s 25 ft. height requirement measured to?
For pitched roofs: To the midpoint of the highest gable or dormer. For flat roofs: To the top of the cornice. For mansard roofs: To the deck line.
Do I have to provide additional parking for an ADU?
No, ADUs are exempt from the off-street parking requirements but any required parking for the single family dwelling must be maintained.
Do I need a separate address for my ADU? How do I get one?
For new construction or additions, email DTEaddress@cincinnati-oh.gov with the site plan before applying for any permits to have the addresses assigned or vetted. We can often provide a same-day response. How the address will be assigned will be on a case-by-case basis. Units may be given a ½ address to the principal residence address.
I’m a developer looking to construct a home with an ADU, how do I comply with the requirements for owner occupancy or designation of a responsible person?
In the ADU registration process, click the “For Sale” option. You will need to record the required covenant prior to the issuance of building permit and affirm that you agree to make the purchaser aware of the registration requirement and that noncompliance with the owner occupancy or responsible person residence requirement is a Class F Civil Offense. You will then be issued a “For Sale Development Intent to Comply with the ADU Registration Certificate.” The new owners of the home will be required to file a registration within 60 days of purchase.
Will the City send out renewal reminder notices?
Yes, a renewal reminder will go out to all registered property owners with ADUs.
What is the penalty for not complying with the owner/responsible person residency requirement?
The penalty for not complying with the requirement for occupancy by the owner or a responsible person is a Class F Civil Offense, which carries a $15,000 fine.
For additional questions, please contact the Zoning Information Line at (513) 352-2430 or zoninginfo@cincinnati-oh.gov.