Building Codes and Regulations

The State of Illinois recently passed legislation (Public Act 103-0510) changing the Capital Development Board Act to require statewide building codes effective 1/1/2025.  Until then, units of local government such as cities and counties can adopt codes of their choice. The best and most accurate answers to building code questions must be answered by your city, village, or county code official.

Commercial buildings in jurisdictions that have not adopted a building code AND state funded buildings.

• New or substantially improved buildings:  IEBC^© and IBC^© (1/1/25 Incl. App G., Excl. Ch 11, 13, 29). Current edition or most recent preceeding edition.¹
• NEC^© Current edition or most recent preceeding edition.¹
• Illinois Energy Conservation Code.^1,2
• Starting 7/1/24 state buildings must comply with the Illinois Stretch Energy Code.^1,3
• Illinois Accessibility Code.^1,4
• Illinois Plumbing Code.^1,5
• Fire Prevention and Safety Rules (includes NFPA 101^©).^1,6  Click here for NFPA 101 applicability.
• Non-state buildings must be inspected by a qualified inspector stating the building complies with the above codes.¹ Click here for more information.

¹Required by 20 ILCS 3105/10.09-1.  ²Required by 20 ILCS 3125/15.  ³Required by 20 ILCS 3125/55.  ⁴Required by 410 ILCS 25/5.  ⁵Required by Title 77 Part 890 Section 890.110.  ⁶Required by Title 41 Part 100 Section 100.3.

Commercial buildings in jurisdictions that have adopted building codes.

• Local codes and amendments.
• Starting 1/1/25 local codes must regulate the  structural design in a manner that is at least as stringent as the IBC^© for new buildings or IEBC^© for existing buildings.¹ 
  
• Illinois Energy Conservation Code.² 
• Illinois Accessibility Code.³ 
• Illinois Plumbing Code.⁴ 
• Fire Prevention and Safety Rules (includes NFPA 101^©).⁵  Click here for NFPA 101 applicability.

¹Required by 20 ILCS 3105/10.18.  ²Required by 20 ILCS 3125/15.  ³Required by 410 ILCS 25/5.  ⁴Required by Title 77 Part 890 Section 890.110.  ⁵Required by Title 41 Part 100 Section 100.3.

Residential buildings in jurisdictions that have not adopted a building code where agreed to by the home purchaser and home builder. 

• New construction:  IRC^© Current edition or most recent preceeding edition OR a municipal/county residential code within 100 miles of the home.  (1/1/24 excluding IV and VII)¹
• Illinois Energy Conservation Code.² 
• Illinois Accessibility Code if owned, leased or financed by a governmental unit.³
• Illinois Plumbing Code.⁴
  
• Fire Prevention and Safety Rules (includes NFPA 101^©).⁵  Click here for NFPA 101 applicability.

¹Required by 815 ILCS 670/15.  ²Required by 20 ILCS 3125/15.  ³Required by 410 ILCS 25/5.  ⁴Required by Title 77 Part 890 Section 890.110.  ⁵Required by Title 41 Part 100 Section 100.3.

Residential buildings in jurisdictions that have not adopted a building code where NOT agreed to by the home purchaser and home builder.

• New construction:  IRC^© Current edition.  (1/1/24 excluding IV and VII)¹
• Illinois Energy Conservation Code.^1,2 
  
• Illinois Accessibility Code if owned, leased or financed by a governmental unit.³
• Illinois Plumbing Code.⁴
  
• Fire Prevention and Safety Rules (includes NFPA 101^©).⁵  Click here for NFPA 101 applicability.

¹Required by 815 ILCS 670/15.  ²Required by 20 ILCS 3125/15.  ³Required by 410 ILCS 25/5.  ⁴Required by Title 77 Part 890 Section 890.110.  ⁵Required by Title 41 Part 100 Section 100.3. 

Residential buildings in jurisdictions that have adopted a building code.

• Local codes and amendments.
• Starting 1/1/25 local codes must regulate the  structural design in a manner that is at least as stringent as the IRC^©. ¹
• Illinois Energy Conservation Code.²
• Illinois Accessibility Code if owned, leased or financed by a governmental unit.³
• Illinois Plumbing Code.⁴
• Fire Prevention and Safety Rules (includes NFPA 101^©).⁵  Click here for NFPA 101 applicability.

¹Required by 20 ILCS 3105/10.18.  ²Required by 20 ILCS 3125/15.  ³Required by 410 ILCS 25/5.  ⁴Required by Title 77 Part 890 Section 890.110.  ⁵Required by Title 41 Part 100 Section 100.3. 

20 ILCS 3105/10.18 requires that all municipalities or counties adopting a new building code or amending an existing building code must provide an identification of the code by title and edition including local amendments to CDB at least 30 days before the effective date of the building code.

Use the County Municipal Code Reporting Form to notify CDB of your new or amended code.

To assist you, CDB provides two directories; one of local building codes and the other listing state regulations and statutes for your convenience.

• Illinois City or County Local Code Directory
• Illinois Construction-Related Statutes and Rules Directory

For more information see our Building Codes & Regulations FAQs or contact us at:

401 South Spring Street
3rd Floor, Stratton Building 
Springfield, IL 62706
CDB.BuildingCodes@illinois.gov
Voice: 217-720-3021
TDD: 217-524-4449