For a building in Illinois, first find the local building code the city, village, or county has adopted and reported to the Capital Development Board, then check that the code analysis cites it together with the state codes that apply whether or not the locality adopted them: the Illinois Energy Conservation Code (the 2024 IECC with Illinois amendments, effective November 30, 2025, or the Illinois Stretch Energy Code where the municipality adopted it or the Board funds the project), the 2018 Illinois Accessibility Code for public facilities and multi-story housing, the Illinois Plumbing Code, and the Fire Prevention and Safety Rules on NFPA 101 (2015) unless the locality enforces a fire code the State Fire Marshal accepts as equal or higher or is a home rule unit with its own fire code (state buildings and state-licensed facilities follow the state rules everywhere). Where no compliant local code exists, record that a new or substantially improved commercial building needs a qualified inspector’s certification against the current or preceding IBC and IEBC, the NEC, and those state codes before anyone occupies it, and route public schools to the regional superintendent, licensed health care to the Department of Public Health, and Chicago work to the city’s own titles. AI can flag conflicts; the design professional, the local building official, and the state agencies decide compliance.
Which Illinois codes apply to a set of drawings?
Illinois sets a floor rather than a single code. Under 20 ILCS 3105/10.18, beginning January 1, 2025 any municipal or county building code must regulate the structural design of new buildings other than residential buildings at least as stringently as the baseline building code, rehabilitation work in existing buildings at least as stringently as the baseline existing building code, and residential buildings (single-family homes and dwellings of two or fewer units) at least as stringently as the baseline residential code. The baselines are the editions of the IBC (including Appendix G), the IEBC, and the IRC first published during the current year or the preceding nine calendar years with the least restrictive structural provisions, and the section limits home rule powers. A municipality or county adopting a new building code edition must identify the model code, edition, and local amendments to the Capital Development Board at least 30 days before it takes effect, and the Board posts them in its Illinois Municipal Code Directory. A municipality or county need not adopt a code at all. Where it has not, or has not identified its code to the Board, the area is a non-building code jurisdiction under 20 ILCS 3105/10.09-1: no one may occupy a newly constructed or substantially improved commercial building there until the owner has contracted for an inspection by a qualified inspector and that inspector files a certification with the municipality or county that the building complies with the current or most recent preceding edition of the IBC (including Appendix G and excluding Chapters 11, 13, and 29) and the IEBC, the current or most recent preceding NEC, the Illinois Energy Conservation Code or Stretch Energy Code, the Illinois Accessibility Code, the Illinois Plumbing Code, and the State Fire Marshal’s rules under the Fire Investigation Act. A commercial building is any building other than a single-family home, a dwelling of two or fewer units, or an exempt farm building, and from January 1, 2025 substantial improvement means work costing 50% or more of the structure’s pre-improvement market value. The requirements in effect on January 1 of the year the permit was applied for, or construction began where no permit is required, apply for the duration of the work, and the qualification rule does not apply to a municipality’s or county’s own enforcement staff. A qualified inspector holds an ICC commercial building inspector certification or an equivalent, has completed a U.S. Department of Labor certified apprentice program, or has filed verification of experience under 71 Ill. Adm. Code 300, which accepts an Illinois architect or engineer license or a State Board of Education plan reviewer and inspector card. For new houses in a non-building code jurisdiction, 815 ILCS 670/15 makes the construction contract adopt a residential code the builder and purchaser agree on, the IRC (current or most recent preceding edition, excluding Parts IV and VII) or a municipal or county residential code in effect within 100 miles; if they do not agree, the energy code, the Illinois Plumbing Code, and the current IRC become part of the contract by law.
The state codes carry their own editions. The Illinois Energy Conservation Code page says the 2024 IECC as amended took effect November 30, 2025 for privately funded commercial buildings and residential buildings, and 71 Ill. Adm. Code 600 Sections 600.300 and 600.400 incorporate the 2024 IECC with the Illinois modifications in Appendix A (amended at 49 Ill. Reg. 15562, effective November 30, 2025). Section 600.110(a) still describes the purpose of the code as adopting the 2021 IECC effective January 1, 2024, so cite the 2024 edition that Sections 600.300 and 600.400 incorporate and confirm with the Board if a reviewer points to Section 600.110. Under 20 ILCS 3125/20 the code applies to any new building for which a municipality or county receives a building permit application, applies to additions, alterations, renovations, and repairs only for the altered portions, and exempts buildings with no conditioned space, buildings using neither electricity nor fossil fuel for comfort conditioning (a service over 100 amps is presumed electric heating unless the code official finds otherwise), historic buildings on the National or Illinois Register or locally designated, and buildings the IECC exempts. Section 15 makes the code the minimum for commercial buildings and the minimum and maximum for residential buildings; under Section 45 and Section 600.440 only a unit of local government that had adopted or reported a code at least equal to the 2006 IECC by May 15, 2009, a municipality of 1,000,000 or more, or a municipality that has adopted the Stretch Energy Code may set more stringent residential standards, while any local government may set more stringent commercial standards. A residential building for the energy code includes multifamily buildings of three stories or less above grade. A local government that does not regulate energy standards need not enforce the code, but construction there is still subject to the Act. Section 600.330 accepts ASHRAE 90.1 User’s Manual forms, COMcheck certificates, comparable materials the AHJ accepts, the design professional’s seal, or the C407 or C410 compliance materials for commercial buildings.
The Illinois Stretch Energy Code replaces the base code only in a municipality that adopts it, separately for residential and commercial buildings, and under 20 ILCS 3125/55(c) it applies to every project the Board authorizes or funds in any part after July 1, 2024; Section 600.220 accepts PHI or PHIUS certification, COMcheck certificates, or the design professional’s seal for State facilities. The editions are labeled differently: the Board’s page calls the current code the 2023 Illinois Stretch Energy Code, effective January 1, 2025, while Sections 600.200 and 600.305 incorporate a 2024 IECC Final Draft with the Appendix B modifications for the commercial stretch code and Appendix C amends the 2021 IECC for the residential stretch code; confirm the stretch edition with the Board. The 2018 Illinois Accessibility Code, 71 Ill. Adm. Code 400, took effect October 23, 2018; Section 400.110 says its drafters primarily adopted the stricter of the state and federal (2010 ADA) standards, and Section 400.120 incorporates referenced standards including the 2015 IBC, ASME A17.1-2013, ASME A18.1-2011, and NFPA 72 (2013). The Illinois Plumbing Code, 77 Ill. Adm. Code 890, was last amended effective April 24, 2014 and governs new plumbing and any work that alters plumbing, and 225 ILCS 320/36 lets a local government adopt a plumbing code at least as stringent or adopt the Department’s code. The Fire Prevention and Safety Rules, 41 Ill. Adm. Code 100, adopt NFPA 101 (2015) with State Fire Marshal modifications, effective January 1, 2020 according to the State Fire Marshal’s Life Safety Code page. The Board’s own pages lag the law: its Illinois Codes page says there is currently no statewide building code and that one will go into effect January 1, 2025, and its Building Codes and Regulations page says local governments may adopt codes of their choice until then, while its FAQ answers that the state has adopted statewide codes for commercial and residential construction in the sense of the structural baseline. The statute has applied since January 1, 2025. All checked November 7, 2026.
Plan review is local for private work. The Board’s FAQ says the state does not perform plan reviews, issue permits, inspect, or issue occupancy permits for privately funded construction, that the local code official is the authority having jurisdiction, and that the Board interprets codes only on projects it manages. It also says a locality whose adopted code does not meet Section 10.18 is treated as a non-building code jurisdiction, and the directory carries the same warning, while Section 10.09-1 defines that term by the absence of an adopted or reported code; ask the Board and the jurisdiction which applies before relying on a local permit alone. The Building Codes and Regulations page lists the codes for each category of building, and for commercial buildings in non-building code jurisdictions and state-funded buildings it gives the IBC and IEBC (current or preceding edition), the NEC, the energy code (the Stretch Energy Code for Board-funded buildings), the Accessibility Code, the Plumbing Code, and the Fire Prevention and Safety Rules.
Accessibility applies whether or not a locality adopted it. 410 ILCS 25/5 gives the Illinois Accessibility Code the force of a building code for public facilities and multi-story housing, requires 20 percent of the dwelling units in new multi-story housing to be adaptable with all common and public use spaces compliant, lets a project whose planning contract was awarded before a new version took effect use the earlier version if construction begins within 12 months, and sends other new housing with four or more dwelling or sleeping units in one structure to HUD’s Fair Housing Accessibility Guidelines. The Board’s accessibility FAQ defines public facilities to include buildings owned, leased, used, or financed by a governmental unit and buildings used by the public or employees for gathering, recreation, lodging, education, employment, institutional care, or buying goods and services, defines multi-story housing as buildings of four or more stories with ten or more dwelling units, says no one can grant a waiver, and says interpretations are project specific (410 ILCS 25/4 allows the Board 30 calendar days; the FAQ says typically two business days). Under Section 5(d), no public facility may be built or altered, and no multi-story housing built, without a statement by an Illinois-registered architect (or engineer, for engineering plans) that the plans comply with the Act and the Code, unless the work costs less than $50,000; the statement is filed with the governmental unit that issues the building permit, or with the county clerk where no unit issues permits. The Board does not enforce the code; the Attorney General’s Disability Rights Bureau does.
The State Fire Marshal’s rules reach most buildings. Under 41 Ill. Adm. Code 100.3, local fire officials enforce the rules under the State Fire Marshal’s direction except where the locality has adopted standards equal to or higher than them, and the office accepts a local code as equal or higher if it is identical, adds to every provision, adopts a later edition of NFPA 101 in its entirety (Section 100.9), is covered by an agreement, adopts the 2012, 2015, or 2018 IBC and IFC (or NFPA 5000) in its entirety, or meets a holistic test with dedicated local inspection and enforcement; later IBC and IFC editions are not listed, so confirm a 2021 or 2024 adoption with the office. Its December 2018 fact sheet says home rule communities may follow the state code or adopt their own fire code, and that state buildings, state-licensed facilities, and other occupancies under the office’s purview follow the state code everywhere; Section 100.3(c)(5) makes state-owned buildings and buildings under the Fire Sprinkler Dormitory Act and Greek Housing Fire Safety Act subject to the office’s inspection and NFPA 101 (2015), and Section 100.3(c)(4) allows the edition the Centers for Medicare and Medicaid Services has adopted in occupancies it regulates. Section 100.7(c) keeps sprinkler requirements from the 2000 edition for existing high-rise buildings and existing assembly occupancies and modifies the day care provisions. The office’s Technical Services Division reviews plans for new construction, additions, renovations, fire alarm and sprinkler systems, and special extinguishing systems, but its plan review services notice says that review is not mandatory under any statute or rule (aboveground tank and LP-gas submittals are), is free, covers only state-adopted codes, and is copied to the local fire chief; it does not review one- and two-family dwellings or townhouses unless used as group homes or day care homes, though it reviews their sprinkler plans.
Three building types have their own reviewers. Public school districts and the charter schools they authorize follow ISBE’s Health/Life Safety Code for Public Schools, 23 Ill. Adm. Code 180: the regional superintendent issues building permits, and under Section 180.60 a project whose design contract is executed on or after January 1, 2025 uses the 2024 IBC with the 2024 IECC, IEBC, IFC (without Chapter 4), IFGC, IMC, and IPMC, the Illinois Accessibility Code instead of IBC Chapter 11, the Illinois Plumbing Code with one section of the 2024 IPC, the State Fire Marshal’s boiler and elevator rules, and ICC 500 (2020) storm shelters for new school buildings with a Group E occupant load of 50 or more or additions that grow the building by 50 percent or more within 24 months. Section 180.200 requires plans by an architect or engineer certifying the code editions used, with signed plan review records before a permit issues; school districts governed by Article 34 of the School Code follow only the rule’s sprinkler section (Section 180.250) and otherwise local building codes, and the State Fire Marshal inspects public schools other than Chicago Public Schools. Licensed health care facilities go to the Department of Public Health, whose Design and Construction Section does their plan reviews. Capital projects under the Board’s authority are State facilities under 20 ILCS 3105/10.20: from January 1, 2026 no local ordinance or permitting requirement is enforced against them except sanitary district or municipal wastewater requirements mandated by law or supported by industry standards, the Board consults the local utility and fire protection providers first, and the section does not apply in a municipality of more than 500,000 inhabitants that has agreements with the Board. Chicago’s titles are covered in the Chicago Building Code guide; permit routing is on the Illinois page, and the model codes have their own guides: IBC, IEBC, IRC, IECC, NFPA 101, and NFPA 70.
Gather the local code, the project category, and each state code the set relies on
Collect the cover sheet and code analysis with every code and edition cited, the occupancy, construction type, area, height, and occupant loads, the life safety plan with exits, rated assemblies, and sprinkler and alarm coverage, the structural general notes with design loads and the code they follow, the energy compliance documents (COMcheck or ASHRAE 90.1 forms, REScheck, or a passive house certification path), the accessibility plans and details with dwelling unit counts, the plumbing risers and fixture counts, the electrical one-lines and notes, the elevator, boiler, kitchen hood, and fire protection drawings, and the specifications.
Add the city, village, or county, whether it is a home rule unit, its adopted building, fire, plumbing, and energy codes and the date it reported them to the Board, the permit application date or construction start, the market value of the existing building for an alteration, and whether the project is a public school, a licensed health care facility, a state-licensed day care or group home, a state-owned building or Board-funded project, or a house built under contract in a place with no code. Read the statutes and rules on ilga.gov, the code lists on the Board’s Building Codes and Regulations page, and the plumbing program on the Department of Public Health’s site.
Trace the Illinois codes and reviewers through the set
| Review question | Sources to compare | Decision to record |
|---|---|---|
| Local code and its report | Cover sheet, code analysis, local ordinance, the jurisdiction’s entry in the Board’s directory | Record the code, edition, and amendments the jurisdiction adopted and reported under 20 ILCS 3105/10.18, and whether it regulates structural design at least to the IBC, IEBC, and IRC baseline. |
| No local code | Project address, permit status, building type, market value of the work, house contract | For a new or substantially improved commercial building, record the qualified inspector who will certify it under Section 10.09-1; for a new house, the residential code the contract adopts under 815 ILCS 670/15. |
| Energy code | Energy notes, COMcheck or ASHRAE 90.1 forms, envelope and MEP schedules, permit application date | Confirm the 2024 IECC with Illinois amendments in effect when the permit application was received, the Stretch Energy Code where adopted or for Board-funded work, and a compliance document Section 600.330 lists. |
| Accessibility | Accessible route, toilet rooms, parking, dwelling unit and story counts, code analysis, architect’s statement | Check public facilities and multi-story housing against the 2018 Illinois Accessibility Code, the adaptable unit share, and the Fair Housing guidelines for other housing of four or more units, alongside the ADA, and record the architect’s compliance statement for work of $50,000 or more. |
| Plumbing | Plumbing notes, riser diagrams, fixture counts, specifications | Confirm the Illinois Plumbing Code or a local plumbing code at least as stringent, and flag IPC or UPC citations the jurisdiction has not adopted. |
| Fire and life safety | Life safety plan, sprinkler and alarm notes, local fire ordinance, licensure | Record whether the local fire code is accepted as equal or higher, a home rule unit has adopted its own, or NFPA 101 (2015) with the State Fire Marshal’s modifications applies, as it does for state-owned buildings and state-licensed facilities. |
| Schools, health care, and State facilities | Owner, funding, licensure, school district, design contract date | Route public school work to the regional superintendent under 23 Ill. Adm. Code 180 and its 2024 codes, licensed health care to the Department of Public Health, and Board projects to the Board. |
Energy documents continue in the IECC and ASHRAE 90.1 guides, existing buildings in the IEBC guide, life safety in the NFPA 101 guide and the NFPA 101A guide for equivalency evaluations, sprinkler and alarm documents in the NFPA 13 and NFPA 72 guides and the fire sprinkler checklist, accessible details in the ADA Standards guide, the Fair Housing Act guide, and the accessibility checklist, school storm shelters in the ICC 500 guide, elevators in the ASME A17.1 guide, plumbing notes in the IPC guide for comparison, and structural notes in the structural drawing checklist. Neighboring state codes are in the Missouri guide, the Indiana guide, the Wisconsin guide, the Iowa guide, and the Kentucky guide.
Example: a retail building in a county with no building code
Hypothetical example. A developer plans a one-story retail building of about 12,000 square feet on an unincorporated site in a county that has not adopted or reported a building code, with construction starting in 2026 and a construction cost well above $50,000. The architect’s code analysis cites the 2021 IBC and notes that no permit is required, the energy notes cite the 2021 IECC, the accessibility sheets cite only the 2010 ADA Standards, the plumbing notes cite the 2021 International Plumbing Code, and the schedule shows the tenant moving in the week construction ends.
The site is in a non-building code jurisdiction, so under 20 ILCS 3105/10.09-1 the building may not be occupied until a qualified inspector files a certification with the county that it complies with the current or most recent preceding IBC (with Appendix G, without Chapters 11, 13, and 29) and IEBC, the NEC, the Illinois Energy Conservation Code, the Illinois Accessibility Code, the Illinois Plumbing Code, and the State Fire Marshal’s rules, using the requirements in effect on January 1 of the year construction began. The Illinois Energy Conservation Code has incorporated the 2024 IECC since November 30, 2025, a retail store is a public facility under the Illinois Accessibility Code, and plumbing follows 77 Ill. Adm. Code 890 rather than the IPC. The Environmental Barriers Act also requires an Illinois architect’s statement that the plans comply with the Illinois Accessibility Code, filed with the county clerk if the county issues no building permits. Confirm the inspector, the code editions, and the occupancy date with the county and the Capital Development Board.
The owner contracts a qualified inspector before construction, the architect rewrites the code analysis with the IBC edition the inspector will certify and the excluded chapters replaced by the state codes, the energy consultant redoes the COMcheck under the 2024 Illinois code, the accessibility sheets are checked against the 2018 Illinois Accessibility Code and the architect files the compliance statement, the plumbing engineer moves the notes to the Illinois Plumbing Code, and the move-in waits for the certification. The finding is a citation and sequence conflict; the qualified inspector and the state agencies decide compliance.
Review an Illinois set with Groundbook
Upload the current drawings and specifications to Groundbook, and state the edition, amendments, and review scope in your instructions. Illinois statutes and administrative rules are free on ilga.gov, and the Capital Development Board posts the Illinois Accessibility Code and the energy code amendments. Upload the local ordinance, 71 Ill. Adm. Code 400 and 600, 77 Ill. Adm. Code 890, 41 Ill. Adm. Code 100, 23 Ill. Adm. Code 180 for a public school, and the relevant sections of 20 ILCS 3105 and 815 ILCS 670 as code files, with the IBC, IEBC, IRC, IECC, NEC, and NFPA 101 editions the project relies on from copies you are licensed to use where the license permits uploading them. See how Groundbook works with local and licensed codes.
Compare the cover sheet, code analysis, life safety plan, and every discipline’s general notes with the architectural, structural, plumbing, mechanical, electrical, fire protection, energy, and accessibility documents. Flag building code editions that differ from the local code in my instructions, energy notes not on the 2024 Illinois Energy Conservation Code or the Stretch Energy Code where my instructions say it applies, accessibility notes that cite only the ADA for a public facility or multi-story housing, plumbing notes on the IPC or UPC where the Illinois Plumbing Code governs, life safety notes that ignore NFPA 101 (2015) where my instructions say the state fire rules apply, and any statement that no review or certification is needed. Use the supplied statutes, rules, ordinance, and model codes and cite both sources.
Groundbook compares the set with reference documents you upload, including licensed codes and standards you hold, and links each potential finding to the note or sheet and to the Illinois statute, rule, ordinance, or model code. It has no built-in library of licensed codes, runs no calculations, and does not design anything. It does not decide whether a place is a non-building code jurisdiction, whether a local fire code is equal to the state rules, or whether a building is a public facility; each finding is a question for the responsible design professional.
Document review does not certify compliance, file a certification of inspection, issue a permit, or replace the design professional, the local building and fire officials, a qualified inspector, the Capital Development Board, the State Fire Marshal, the Department of Public Health, the regional superintendent, or the Attorney General.