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Additional Dwelling Units (ADU) Program
The Additional Dwelling Units (ADU) Ordinance was first approved by Chicago City Council in 2020, resulting in the creation of five ADU Pilot Areas. In September 2025, City Council voted to expand the ADU ordinance beyond the pilot program allowing for ADU access more broadly across Chicago.
The City of Chicago Municipal Code distinguishes ADUs between “conversion” and “coach house” units. A conversion unit is connected to the existing building such as within an attic or basement while a coach house is a separate, detached structure. Some more common names for ADUs include backyard houses, granny flats, and carriage houses.
ADUs were common in Chicago throughout the first half of the 20th century, but their construction was prohibited starting in 1957 due to zoning regulations that added parking requirements and banned secondary residential structures.
The recently amended Chicago Municipal Code allows for the creation of new residential dwelling units in areas where zoning previously restricted doing so. This provides many public benefits including providing an avenue for property owners to earn additional income by renting these units and creating separate living space for multi-generational families.
View the entire Section 2-44-106 Additional Dwelling Units of the Chicago Municipal Code.
Check your address on the ADU Eligilbiltiy Map!
The process to establish an ADU involves working with multiple experts and City of Chicago Departments. The first steps in this journey involve learning about your property's eligibility and requirements, then submitting an application for pre-certification through the Department of Housing (DOH).
Important note: Please be aware that a DOH ADU pre-certification does not automatically guarantee that your project is permissible. After a pre-certification approval letter is issued, all ADU projects must still obtain the necessary permits via the Department of Buildings (DOB) before any construction can begin.
For inquiries please reach out to the Department of Housing's ADU team at ADU@cityofchicago.org.