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 February 1, 2021, the State Building Code includes:


  • 2018 International Building Code – as amended and adopted by Washington State (Includes adoption of Appendix E and ICC/ANSI A117.1-2009, and the 2018 International Existing Building Code and 2018 International Swimming Pool and Spa Code)
  • 2018 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)
  • 2018 International Mechanical Code – as amended and adopted by Washington State (Includes adoption of 2018 International Fuel Gas Code, 2018 NFPA 58 & 2017 NFPA 54)
  • 2018 International Fire Code – as amended and adopted by Washington State
  • 2018 Uniform Plumbing Code – as amended and adopted by Washington State  (Includes adoption of Appendices A, B and I) NOTE: See also WSEC Section C404 for additional piping requirements
  • 2018 Washington State Energy Code:

Additional Information


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

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