Last updated: March 21, 2026
ADU Checker is a free preliminary screening tool that provides automated site analysis for Accessory Dwelling Unit (ADU) eligibility in Chicago, Illinois. Our analysis is based on publicly available data from the City of Chicago, Cook County, and federal agencies.
Analysis provided by ADU Checker is for informational purposes only and does not constitute legal, financial, architectural, or professional advice. Zoning regulations, permit requirements, and property data may change. Always verify findings with the City of Chicago Department of Buildings and consult qualified professionals before making decisions.
ADU Checker uses analytics cookies (Google Analytics) that are optional and only activated when you provide consent via our cookie banner. For full details, see our Privacy Policy.
Our analysis relies on third-party data sources including the Chicago Open Data Portal, City of Chicago ArcGIS services, Cook County Assessor, FEMA, and others. While we strive for accuracy, we cannot guarantee that all data is current, complete, or error-free. Data sources may have delays, omissions, or inaccuracies beyond our control.
You agree not to:
The ADU Checker analysis engine, user interface, and original content are protected by copyright. The underlying public data from government sources remains in the public domain. You may not reproduce, distribute, or create derivative works from our proprietary analysis without written permission.
ADU Checker is provided “as is” without warranties of any kind. We are not liable for any damages arising from your use of the service, reliance on analysis data, or decisions made based on our results.
These terms are governed by the laws of the State of Illinois. Any disputes arising from or relating to these terms or your use of the service shall be resolved in the courts of Cook County, Illinois.
We may update these terms from time to time. Continued use of the service after changes constitutes acceptance of the updated terms.
Questions about these terms? Email us at support@lucenlabs.com.