Accessory Dwelling Units
The City of Chicago adopted an ordinance re-legalizing accessory dwelling units on Wednesday, December 16, 2020. It allows a backyard house or interior ADU at properties in one of the 5 pilot areas and also within a RS-2, RS-3, RT, or RM zoning district.
Properties with 5 or more units can have 2 or more interior ADUs, but no backyard house.
Look up your address in the search field above to check if it's in one of the 5 pilot areas and it's within a RS-2, RS-3, RT, or RM zoning district.
4-minute ADU explainer video
Get building
1. Check your address
Look up an address to check eligibility
3. Contact an architect or builder
More resources
Understanding the law
Municipal Code of Chicago section on coach houses (17-9-0201-F)
Municipal Code of Chicago section on conversion units (17-9-0131)
Eligible areas
View a map of the 5 pilot areas
Not eligible? Here's how to build an ADU outside a pilot area
Design ideas
Review the "Better Basement Units" manual from NHS
Zoning worksheet to calculate how large a backyard house can be
News
10 ADU permits have been issued as of November 8, 2021
Construction & consultation grants are open (Nov. 9, 2021)
Preservation professionals are overwhelmingly in favor of ADUs
Data Notes
Where are the most eligible properties?
There are five pilot areas: Southeast, South, West, Northwest, and North. Based on our estimation there are 92,322 eligible properties*. Use the Property Finder tool within each Place Snapshot (linked below) to map and download a list of these properties. They are spread across the pilot areas like so:
| Pilot area | Quantity |
|---|---|
| Southeast | 10,030 |
| South | 37,279 |
| West | 9,509 |
| Northwest | 15,348 |
| North | 20,156 |
Data notes
A plurality of these properties (49.2%) are in RS-3 zoning districts; 31.1% are in RS-2, and 15.1% are in RT-4. The remaining ~4.6% are in the 7 other "R" zoning districts.
* For our analysis, we included only these property classes (defined by the Cook County Assessor) that have a residential component: 2-11, 2-12, 2-13, 2-25, 3-13, 3-14, 3-15, 3-18, 3-91, 3-96, 4-18, 9-00, 9-13, 9-14, 9-15, 9-18, 9-91, 9-96, 9-97, 2-02, 2-03, 2-04, 2-05, 2-06, 2-07, 2-08, 2-09, 2-34, 2-78.
We also excluded condo buildings. Condo associations are allowed to participate, but the legalities and likelihood of doing so is up to each association and their rules. Vacant lots were excluded, too; a backyard house is allowed to be built first on a vacant lot in only the North (203 vacant lots) and Northwest (593 vacant lots) pilot areas.