Building Construction Codes

The Washington State Building Code is comprised of several different codes. Most are national model codes (International Codes) adopted by reference and amended at the state level. Others, such as the Washington State Energy Code, are state-written state-specific codes.


Beginning March 15, 2024, the State Building Code includes:

  • 2021 International Building Code – as amended and adopted by Washington State (Includes adoption of Appendix E and ICC/ANSI A117.1-2017, and the 2021 International Existing Building Code and 2021 International Swimming Pool and Spa Code) 
  • 2021 International Residential Code – as amended and adopted by Washington State (Includes adoption of Appendices F, Q, and U; Chapter 11 and Chapters 25 through 43 are not adopted) 
  • 2021 International Mechanical Code – as amended and adopted by Washington State (Includes adoption of 2021 International Fuel Gas Code, 2021 NFPA 58 & 2020 NFPA 54) 
  • 2021 International Fire Code – as amended and adopted by Washington State 
  • 2021 Uniform Plumbing Code – as amended and adopted by Washington State  (Includes adoption of Appendices A, B, I and M) NOTE: See also WSEC Section C404 for additional piping requirements 
  • 2021 Washington State Energy Code: 
    • WAC 51-11C (Commercial, 2nd Printing, Including Section C403.1.4)) 
    • WAC 51-11R (Residential, including Appendix A, Default Heat Loss Coefficients, from the Commercial Provisions)  
  • 2021 International WUI Code – as amended and adopted by Washington State (Includes adoption of Includes adoption of Appendix B, C, and D) 
  • Optionally, Compliance with the 2021 International Green Construction Code (IgCC), including Appendix L, LEED standards, and Appendix M, residential compliance with the National Green Building Standard (ICC 700). 

Additional Information 

Here are some additional links to resources you may find helpful: 

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