International Residential Code
Illinois leaves the IRC to cities and counties
Illinois leaves the IRC to cities and counties. Adopted by General Assembly (statute); municipalities and counties adopt local codes. The legal citation is 20 ILCS 3105/10.18; 815 ILCS 670/15.
Record of adoption
Edition in force
Local adoption
Partial
- Legal citation
- 20 ILCS 3105/10.18; 815 ILCS 670/15
- Adopted by
- General Assembly (statute); municipalities and counties adopt local codes
- Second reading
- Applies
- Local option
Cities and counties adopt their own residential codes; there is no statewide residential code. From Jan 1, 2025, local codes must regulate residential structural design at least as strictly as the least restrictive IRC edition first published in the current or preceding 9 years; no single edition is named, so edition is null.
Exceptions
- Floor covers structural design only
How Illinois adopts the IRC
The statute defines the baseline as a rolling ten-year window of ICC editions. Local governments adopt their own residential codes and report them to CDB. P.A. 103-510 created the requirement.
Cycle. Rolling baseline set by statute; local adoption irregular
Laws, rulings, and other actions
- LegislationP.A. 103-0510 (SB 2368, 103rd General Assembly)
Requires municipal and county building codes to meet a rolling IBC/IEBC/IRC structural baseline from Jan 1, 2025, and sets IBC/NEC defaults for jurisdictions without a building code.
Enacted 2023, effective Jan 1, 2024; local structural-design floor begins Jan 1, 2025
ilga.gov (opens in a new tab)
How it was checked
Partial
Researched in the state’s own record. The seal stays broken until the passage is on file word for word.
Read twice: a second, blind reading of the state’s record agreed with the first on .
The state’s record was last read on , from three source pages.
Evidence 3 sources
Sources for the record itself come first, the state’s own records ahead of others. A label marks a source about something else, such as an exception. A source marked secondary is not the state’s own record.
20 ILCS 3105/10.18 Identification of local building codesIllinois General Assemblyilga.gov (opens in a new tab)StatuteRetrieved Building Codes and RegulationsIllinois Capital Development Boardcdb.illinois.gov (opens in a new tab)Agency pageRetrieved About the note
“the current edition of the International Residential Code shall, by law, be adopted as part of the construction contract.”
815 ILCS 670/15 Adoption of residential building codeIllinois General Assemblyilga.gov (opens in a new tab)StatuteRetrieved
Tracker cross-checks
Code adoption trackers are a cross-check. They are not Illinois’s own record.
ICC’s code adoption mapCross-checkAgrees with the record
X (local option / not standard for all buildings); chart as of 2026-04