ADU (Accessory Dwelling Unit) Permit in Chicago (2026)
ADU (Accessory Dwelling Unit) permit requirements, fees, and process for Chicago, IL. Find out if you need a permit and how to apply.
Yes, a ADU (Accessory Dwelling Unit) permit is required in Chicago, IL.
A ADU (Accessory Dwelling Unit) permit is required in Chicago, IL. The Chicago Department of Buildings handles permit applications for Chicago. Below you will find the current thresholds, fees, and process for obtaining a adu (accessory dwelling unit) permit in Chicago.
When Is a Permit Required?
When a ADU (Accessory Dwelling Unit) Permit Is Required in Chicago: All ADU construction
Permit Fees
ADU (Accessory Dwelling Unit) Permit Fees in Chicago: $1,500–$6,500. Estimated timeline: 3-6 months.
Estimated timeline: 3-6 months
How to Get a ADU (Accessory Dwelling Unit) Permit in Chicago
Verify whether your project meets the permit threshold in Chicago: All ADU construction.
Prepare your permit application and plans. Contact the Chicago Department of Buildings at https://www.chicago.gov/city/en/depts/bldgs.html for required documentation.
Submit your application online at https://www.chicago.gov/city/en/depts/bldgs/provdrs/permits.html or in person at the Chicago Department of Buildings.
Pay the permit fee: $1,500–$6,500.
Wait for plan check approval. Estimated timeline: 3-6 months.
Schedule required inspections through https://www.chicago.gov/city/en/depts/bldgs/provdrs/inspect.html. All inspections must pass before project is finalized.
Important: Chicago Department of Buildings and Chicago DPD both involved. Owner-occupancy affidavit required. ADU Ordinance compliance required.
Chicago Department of Buildings
Phone: (312) 744-5000
Website: https://www.chicago.gov/city/en/depts/bldgs.html
Online Permits: https://www.chicago.gov/city/en/depts/bldgs/provdrs/permits.html
Hours: Mon-Fri 8:00am-4:30pm
Frequently Asked Questions
Can I build an ADU in Chicago?
Yes. Chicago's ADU Ordinance, expanded citywide in July 2022, allows both attached ADUs (basement or attic conversions) and detached coach houses (rear-yard ADUs typically built over a garage). Owner-occupancy is required — you must live in either the primary unit or the ADU. No replacement parking is required. A building permit from the Chicago Department of Buildings is required.
What is a coach house in Chicago, and is it the same as an ADU?
Yes. In Chicago, a coach house is the traditional term for a detached ADU — typically a 1- or 2-story structure built over a rear garage, accessed from the alley. Chicago's ADU Ordinance specifically authorizes coach houses up to 1,000 sqft and 22 ft tall. They are built in the rear yard, behind the principal building. Chicago has a rich history of coach houses from the late 19th and early 20th centuries.
How do I find the zoning of my Chicago property?
Use the City of Chicago Zoning Map at webapps1.chicago.gov/zoneinfo/ — enter your address to find zone designation, applicable district standards, and special overlay zones. You can also check the Chicago Zoning Ordinance (Title 17) at codelibrary.amlegal.com.
Are short-term rentals allowed in Chicago?
Yes, with a license. The Chicago Shared Housing Ordinance (effective 2016) requires a Vacation Rental License or Shared Housing Host Registration ($125/year). Properties in buildings where the condo or co-op association has voted to ban short-term rentals are prohibited. Chicago collects a 4.5% Shared Housing Surcharge plus state hotel tax.
What are the setbacks for a standard Chicago bungalow lot?
In RS-3 (the most common single-family zone for Chicago bungalows), setbacks are: 15 ft front, 2 ft side (minimum — many have 2 ft on one side and 0 on the other with a shared driveway), and 30 ft rear. Chicago's standard lot is 25 ft wide by 125 ft deep. The rear yard is typically used for detached garages accessed from the alley.
Source: Chicago Building Code — ADU (Accessory Dwelling Unit) Requirements. Last verified April 3, 2026. View source