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Cook County, IL Building Safety: Green Building Code (2026)

Some Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified August 2026

Key Facts

Code adopted
2018 International Energy Conservation Code
Applies to
Unincorporated Cook County only
Chapters adopted
Ch. 1 Part 1; Chapters 2-6
Enforced by
Building Commissioner, Building Department
Adopted by
Ord. No. 21-3425, 7-29-2021

Summary

Unincorporated Cook County adopts the 2018 International Energy Conservation Code by reference for new commercial and residential construction, setting the county's baseline green building energy standards administered by the Building Commissioner.

City-specific rules exist: Chicago, and Evanston have their own green building code rules that differ from Cook County's county-level regulations. If you live in one of those cities, check the city-specific page instead.

The following provisions of the 2018 International Energy Conservation Code are hereby adopted by reference to provide the regulations with respect to energy conservation of buildings and structures in unincorporated Cook County, Illinois: Of the IECC-Commercial Provisions: Chapter 1, Part 1; and Chapters 2 through 6. Of the IECC-Residential Provisions: Chapter 1, Part 1; and Chapters 2 through 6. The above provisions are applicable in full force and effect as if set out at length in this Code.

Source: Cook County Code of OrdinancesView official code

Full Breakdown

Cook County Code Section 102-125 adopts specific chapters of the 2018 International Energy Conservation Code by reference -- Chapter 1 Part 1 and Chapters 2 through 6 of both the IECC-Commercial and IECC-Residential provisions -- to regulate energy conservation for buildings and structures built in unincorporated Cook County. Any IECC provision not on that list is excluded. The section is one of six model codes collectively titled the Cook County Building Code, administered and enforced by the Building Commissioner and Building Department, with permits required before covered construction begins.

Violations & Fines

Building without a permit covering IECC-regulated work, or noncompliant insulation, glazing or HVAC efficiency, is a Building Code violation enforced by the Building Commissioner through permit denial, inspection, or Administrative Hearings.

Frequently Asked Questions

Does Cook County have a green building or energy code?
Yes, but only in unincorporated Cook County. Section 102-125 adopts the 2018 International Energy Conservation Code by reference for new commercial and residential construction there.
Does this energy code apply in Chicago or other Cook County towns?
No. It governs unincorporated Cook County only. Chicago and the county's 130-plus municipalities enforce their own separately adopted building and energy codes.

Sources & Official References

Other rules in Cook County

All Cook County rules

Compare Cook County to another location·View the Illinois building safety overview

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