Chicago ADU Permit Checklist

A step‑by‑step guide for Chicago residents that lists every drawing, form and city‑specific clearance needed to move an ADU from concept to approved permit.

2,664,452 residents · 607 km²

Building Code

Contact AHJ

Climate Zone

Varies

Permit Time

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AHJ

Local Authority

The City of Chicago’s Building Code, reinforced by Ordinance 13‑44‑040, sets clear expectations for accessory dwelling units. Whether you are adding a backyard cottage or converting a garage, the department requires a complete set of scaled drawings, professional stamps, and proof of compliance with fire‑code and zoning rules. This guide walks you through each required document, links to the online portal, and highlights neighborhood overlay considerations that often affect setbacks and parking. With the right paperwork in hand, Chicago homeowners can streamline the review process and keep their projects on schedule. Blueprints AI helps you assemble the files so the city sees a complete, permit‑ready package.

What the Chicago Building Department Requires

First, prepare a full set of construction drawings on 24‑by‑36‑inch sheets, using a 1/4"=1'-0" scale. The title block must include the project name, address, filing date, and the name of the licensed architect or engineer. All sheets need the official city seal, professional stamps, and signatures of the responsible design professionals.

Next, submit the required forms: the ADU Application, Zoning Verification, Parking Waiver (if applicable), and the Fire‑Code Compliance Checklist. Attach a site plan showing setbacks, lot coverage, and any overlay district restrictions. Fees are calculated based on square footage, and the online portal will generate the total after you upload the documents. Once the package is complete, the department typically reviews it within 30 days, though overlay reviews may add extra time.

Common Project Types

Garage Conversion

Turn an existing garage into a legal, livable ADU with minimal structural changes.

New Backyard Cottage

Build a detached unit in the rear yard, meeting Chicago setback and height limits.

Basement ADU

Create a separate dwelling below grade while complying with egress and fire codes.

Side‑Yard Unit

Add a compact unit on the side of the lot, respecting overlay district rules.

Building Department

Authority: Chicago Department of Buildings
Address: 50 West Washington, Chicago
Permit Portal: ePlan Chicago
Fees: Fees are based on project size and type and are calculated during the online submission.

Frequently Asked Questions

Do I need a parking space for my ADU in Chicago?

Parking requirements depend on the zoning district and the size of the ADU. In many residential zones a single off‑street space is required, but a parking waiver can be granted if the property is within a half‑mile of public transit or if the ADU is under 500 square feet.

What setbacks apply to a backyard ADU?

Chicago generally requires a minimum of 5 feet from the side property line and 10 feet from the rear lot line. Overlay districts may impose additional buffers, so check the site‑specific overlay map before finalizing the design.

How long does the city take to approve an ADU permit?

The standard review period is about 30 days after a complete submission. If the project triggers an overlay review or needs additional fire‑code clarification, the timeline can extend by two to three weeks.

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