# Illinois Building Code: Which Editions Are Adopted > Which I-Code editions Illinois is recorded as adopting, what the record does not cover, and how to confirm the edition governing a project. - Canonical: https://harth.build/resources/code-adoption/illinois-building-code-adoption/ - Last updated: 2026-09-07 - Data source: Adopted editions transcribed from the [ICC Master I-Code Adoption Chart (January 2024)](https://www.iccsafe.org/wp-content/uploads/Master-I-Code-Adoption-Chart-1.pdf), reproduced with the chart's own legend so an “X” is not mistaken for a statewide adoption. ICC notes that not all jurisdictions report their adoptions and publishes updates at [iccsafe.org/adoptions](https://www.iccsafe.org/adoptions). The current edition, its effective date and the state amendments are published by [Illinois's official building-code publication](https://cdb.illinois.gov/business/codes.html), which controls. ## Key facts | Fact | Value | | --- | --- | | Current adoption | No statewide building code; a statewide energy code based on the 2021 IECC took effect 1 January 2024 (checked 2026-09-08 against Illinois Capital Development Board) | | Energy | Illinois Energy Conservation Code (2021 IECC basis), statewide (as published by the authority named below) | | Building and residential | Local adoption; no statewide edition (as published by the authority named below) | | Cross-state chart record | Some jurisdictions only IBC (ICC chart, January 2024 — older than the record above) | ## Direct answer No statewide building code; a statewide energy code based on the 2021 IECC took effect 1 January 2024 in Illinois. Illinois Energy Conservation Code — the state's first custom energy code, based on the 2021 IECC with Illinois amendments. Building and residential codes are adopted locally. Municipalities may adopt energy requirements more stringent than the state code, but not less. This was checked on 2026-09-08 against Illinois Capital Development Board, which is the source that controls. Record the permit application date with it: a code change normally applies from an effective date, and an application filed before that date is usually reviewed under the previous edition. The cross-state comparison further down this page comes from the ICC adoption chart dated January 2024, so where the two disagree the record above is the newer one. *Content and cited inputs reviewed by [Scott Barrington](https://nz.linkedin.com/in/barrington), Harth founder and architectural technology specialist · Published 2026-09-07 · Updated 2026-09-07.* ![Code-adoption status diagram: Illinois Building Code: Which Editions Are Adopted](https://efwwel0vyt9vy5so.public.blob.vercel-storage.com/images/code-adoption/illinois-building-code-adoption/diagram-1344.webp) *Which I-Code editions Illinois is recorded as adopting, what the record does not cover, and how to confirm the edition governing a project.* ## What must be verified before using this guidance? **No statewide building code; a statewide energy code based on the 2021 IECC took effect 1 January 2024.** Illinois Energy Conservation Code — the state's first custom energy code, based on the 2021 IECC with Illinois amendments. | Discipline | Adopted | | --- | --- | | Energy | Illinois Energy Conservation Code (2021 IECC basis), statewide | | Building and residential | Local adoption; no statewide edition | **Local adoption:** Building and residential codes are adopted locally. Municipalities may adopt energy requirements more stringent than the state code, but not less. Checked 2026-09-08 against [Illinois Capital Development Board](https://cdb.illinois.gov/business/codes/illinois-energy-codes.html). Confirm the edition and effective date for the specific permit jurisdiction before relying on it. ## The cross-state record For comparison across states, every I-Code the ICC Master I-Code Adoption Chart (January 2024) tracks, as it records Illinois. Where this disagrees with the record above, the record above is newer: | Code | Recorded adoption | | --- | --- | | International Building Code (IBC) | Some jurisdictions only | | International Residential Code (IRC) | Some jurisdictions only | | International Fire Code (IFC) | Some jurisdictions only | | International Mechanical Code (IMC) | Some jurisdictions only | | International Plumbing Code (IPC) | Some jurisdictions only | | International Private Sewage Disposal Code (IPSDC) | Some jurisdictions only | | International Fuel Gas Code (IFGC) | Some jurisdictions only | | International Green Construction Code (IgCC) | Some jurisdictions only | | International Energy Conservation Code — Residential (IECC-R) | 2021 | | International Energy Conservation Code — Commercial (IECC-C) | 2021 | | International Property Maintenance Code (IPMC) | Some jurisdictions only | | International Existing Building Code (IEBC) | Some jurisdictions only | | International Swimming Pool and Spa Code (ISPSC) | Some jurisdictions only | | ICC Performance Code (ICCPC) | Some jurisdictions only | | International Wildland-Urban Interface Code (IWUIC) | Some jurisdictions only | | International Zoning Code (IZC) | Some jurisdictions only | | ICC 700 National Green Building Standard (ICC 700) | Some jurisdictions only | Illinois has a recorded edition year for 2 of the 17 codes: 2021 for the residential energy and commercial energy codes. The building, residential, fire, mechanical, plumbing, private sewage, fuel gas, green construction, property maintenance, existing buildings, swimming pool and spa, performance, wildland-urban interface, zoning and green building standard codes appear as adopted by individual state or local agencies rather than as a statewide standard, so whether they apply depends on the permit jurisdiction for the project address. Source: [ICC Master I-Code Adoption Chart (January 2024)](https://www.iccsafe.org/wp-content/uploads/Master-I-Code-Adoption-Chart-1.pdf). ## How Illinois compares with its neighbours | State | Building (IBC) | Residential (IRC) | Residential energy (IECC-R) | | --- | --- | --- | --- | | **Illinois** | Some jurisdictions only | Some jurisdictions only | 2021 | | Indiana | 2012 | 2018 | 2018 | | Wisconsin | 2015 | Not adopted | 2009 | | Missouri | Some jurisdictions only | Some jurisdictions only | Some jurisdictions only | | Iowa | 2015 | 2015 | 2012 | Indiana, Wisconsin and Iowa differ from Illinois on the building code alone. A practice working across that border is working to two editions, whatever the office standard says. ## Where Illinois sits in the national record Illinois is one of **7 jurisdictions with no statewide IBC edition** in this record. Adoption runs through individual state agencies or local programmes instead, so there is no single answer for the state and the permit jurisdiction for the address decides. Across all 17 codes the chart tracks, Illinois has a recorded edition for **2**, which ranks it 46th of 51. A low count is not a gap in regulation — it usually means the state legislates through its own documents, or leaves the discipline to local adoption. ## What the chart does and does not tell you The chart's own legend matters more than the numbers: - **An edition year** means one or more state or local agencies adopted that edition. It does not mean every building in the state is designed to it. - **“Some jurisdictions only”** is the chart's `X`: the code is in use somewhere in the state but is not the standard for all buildings. - **“Not adopted”** is a blank cell — no state or local jurisdiction reported adopting that code. - **“State-written code”** means the state publishes its own document in place of the model edition, so the model text is a reference, not the law. ICC states plainly that not every jurisdiction notifies it of an adoption, and this chart is dated **January 2024**. Treat it as the starting point for a search, never as the answer. ## How to confirm the edition that governs a Illinois project 1. Open [Illinois's official building-code publication](https://cdb.illinois.gov/business/codes.html) and find the currently adopted code list with its effective date. 2. Check whether the permit authority for the project address is the state or a local programme with its own adoption. 3. Read the state amendments alongside the model edition — an amended table or definition changes the requirement even when the edition matches. 4. Record the permit application date. A code change usually applies from an effective date, and applications filed before it are normally reviewed under the previous edition. 5. Get the answer in writing from the authority having jurisdiction before it drives a design decision. ## Illinois code-basis worksheet Fill this in once per project and keep it with the drawing set. Every row is a question a plan reviewer can ask, and the answer changes with the address and the application date, not with the state. | Item | Project entry | | --- | --- | | Project address and permit jurisdiction | | | State programme or local programme as AHJ | | | Building / residential edition and effective date | | | Energy code edition (or state-written code) | | | Fire, mechanical, plumbing and fuel-gas editions | | | Accessibility standard and edition | | | State amendments consulted (citation) | | | Local amendments consulted (citation) | | | Permit application date and vesting rule | | | Written AHJ confirmation (date, name) | | **This worksheet records a determination; it does not make one.** The authority having jurisdiction decides which edition and which amendments apply. ## Where can you explore related guidance? - [Explore all code adoption guidance](https://harth.build/resources/code-adoption.md) - [Indiana Building Code: Which Editions Are Adopted](https://harth.build/resources/code-adoption/indiana-building-code-adoption.md) - [Wisconsin Building Code: Which Editions Are Adopted](https://harth.build/resources/code-adoption/wisconsin-building-code-adoption.md) - [Missouri Building Code: Which Editions Are Adopted](https://harth.build/resources/code-adoption/missouri-building-code-adoption.md) - [Iowa Building Code: Which Editions Are Adopted](https://harth.build/resources/code-adoption/iowa-building-code-adoption.md) ## Sources and method Adopted editions transcribed from the [ICC Master I-Code Adoption Chart (January 2024)](https://www.iccsafe.org/wp-content/uploads/Master-I-Code-Adoption-Chart-1.pdf), reproduced with the chart's own legend so an “X” is not mistaken for a statewide adoption. ICC notes that not all jurisdictions report their adoptions and publishes updates at [iccsafe.org/adoptions](https://www.iccsafe.org/adoptions). The current edition, its effective date and the state amendments are published by [Illinois's official building-code publication](https://cdb.illinois.gov/business/codes.html), which controls. ### Source links - [iccsafe.org](https://www.iccsafe.org/wp-content/uploads/Master-I-Code-Adoption-Chart-1.pdf) - [iccsafe.org](https://www.iccsafe.org/adoptions) - [cdb.illinois.gov](https://cdb.illinois.gov/business/codes.html) - [cdb.illinois.gov](https://cdb.illinois.gov/business/codes/illinois-energy-codes.html) ## Frequently asked questions ### Which building code edition does Illinois use? The ICC Master I-Code Adoption Chart (January 2024) does not record a single statewide IBC edition for Illinois. Adoption there runs through individual state or local agencies, so the governing edition depends on the permit jurisdiction for the project address rather than on a statewide rule. ### Why does this page not simply state today's code? Because the underlying record is dated. The ICC Master I-Code Adoption Chart (January 2024) is the most complete cross-state source available, and ICC notes that not every jurisdiction reports its adoptions. Publishing it with its date attached and sending you to Illinois's official building-code publication is honest; publishing an undated “current edition” would not be. --- - Continue in Harth (open this topic in the Harth agent): https://app.harth.build/agent?context=%2Fresources%2Fcode-adoption%2Fillinois-building-code-adoption%2F - View this page in a browser: https://harth.build/resources/code-adoption/illinois-building-code-adoption/ - All resources for agents: https://harth.build/llms.txt