New Illinois State Building Code Takes Effect – Are You Ready?

Until this year, Illinois lacked a unified building code at the state level—though it did have several individual codes in place. However, there was no overarching standard for general building practices. Instead, building codes were adopted at the local level, leading to a patchwork system where some jurisdictions enforced their own codes while others had none at all.

With the passage of Public Act 103-0510, that is changing. Effective January 1, 2025, every area in Illinois must implement a building code that meets the minimum standards set by the International Code Council (ICC)—regardless of whether they previously had a code in place. By June 1, 2025, all municipalities and counties must confirm their codes align with the baseline statewide requirements.

Key Changes Under the New Illinois State Building Code

• A True Statewide Code for the First Time: Municipalities and Counties must now meet the minimum construction standards of the International Building Code including Appendix G, International Existing Building Code, and International Residential Code.
• Applies to All Municipalities and Counties Under the new statewide requirement, every municipality and county in Illinois must have a building code that aligns with minimum standards. Jurisdictions without an existing code or building department are not required to adopt a code but builders and home buyers must ensure they follow the “baseline” code, which aligns with International Code Council (ICC) standards from one of the past three code cycles—specifically, the 2018, 2021, or 2024 editions. Areas with existing codes must verify that their standards are at least as stringent as those established by the ICC within the last nine years. Municipalities with adopted codes must ensure their codes are up to date by June 1. If a municipality without a code wishes to adopt one, they must do so by June 1 as well.
• Standardized Safety and Structural Requirements: The law requires that all communities—urban, suburban, and rural—follow the same core safety and structural guidelines, creating consistency across the state.
• Fast-Approaching Deadline: Municipalities and counties have until June 1, 2025, to update their codes and submit their compliance documentation to the Illinois Capital Development Board (CDB).

How This Impacts Municipalities, Counties, and Developers

This shift comes as a surprise to many jurisdictions, and the race is on to meet the compliance deadline. Local governments, developers, and construction professionals will need to evaluate existing regulations, adopt necessary updates, and establish enforcement mechanisms—all within the next several months.

Our Building and Code team at HR Green offers a comprehensive suite of services tailored to meet your needs. From code reviews and inspections to navigating the approval process, our certified professionals bring decades of experience to help municipalities and developers meet the new requirements.

How HR Green Can Assist:

• Code Review and Compliance Audits – Assessing current codes and ensuring alignment with the new statewide requirements.
• Plan Reviews and Inspections – Evaluating new projects to verify compliance with structural, safety, and energy standards.
• Implementation Strategy and Consulting – Providing a roadmap to meet deadlines and avoid potential enforcement issues.

Act Now to Meet the June 1, 2025 Deadline

The transition to a statewide building code is a major shift for Illinois municipalities and counties. Whether your jurisdiction has an existing code that needs updating or is adopting a code for the first time, HR Green is here to help.

Don’t wait until the last minute—contact us today! Let’s prepare your projects to be compliant and excel in safety and efficiency under the new Illinois State Building Code.

Download a PDF