International Residential Code
Washington enforces the 2021 IRC
The 2021 International Residential Code (IRC) has been in force in Washington since Mar 15, 2024. It applies statewide. Adopted by Washington State Building Code Council. The legal citation is WAC 51-51-003; WAC 51-51-008; chapter 19.27 RCW.
Record of adoption
Edition in force
2021 IRC
State Building Code Adoption and Amendment of the 2021 Edition of the International Residential Code (chapter 51-51 WAC)
Verified
- In force since
- Legal citation
- WAC 51-51-003; WAC 51-51-008; chapter 19.27 RCW
- Adopted by
- Washington State Building Code Council
- Second reading
- Applies
- Statewide
- State amendments
- Major
- Also called
- WAC 51-51, 2021 IRC with Washington amendments
A follow-up reconciliation rule (WSR 23-23-104, 36 sections of chapter 51-51 WAC) took effect Mar 16, 2024, a day after the Mar 15, 2024, implementation date. The state amendments are rated substantial because chapter 51-51 WAC has about 70 active amended sections.
Exceptions
- Counties and cities may adopt local amendments to the state codes; the Council must approve or deny those that apply to single-family or multifamily residential buildings (RCW 19.27.074(1)(b)).
Coming next
- 2024 IRCPartialPlanned for May 3, 2027ProposedWAC 51-51; CR-102 listed by SBCC as WSR 26-10-071
Same schedule as the IBC: comment period May 6, 2026, to Jun 12, 2026, hearings Jun 10, 2026, and Jun 12, 2026, final adoption targeted Oct 16, 2026. May 3, 2027, is the proposed effective date, not final until a CR-103 is filed. The CR-102 had listed Aug 28, 2026, as intended adoption.
How Washington adopts the IRC
The State Building Code Council adopts each ICC edition with Washington amendments by rule under the Administrative Procedure Act (CR-101, CR-102 with public hearings, CR-103) on a three-year cycle that follows the model-code cycle (RCW 19.27.031). Statewide decisions must be made before December 1 and may not take effect before the end of the next regular legislative session (RCW 19.27.074(5)(c)), a window in which the Legislature can act by statute, but no legislative approval vote is required for these codes. ESSB 6291 (2024) restructured Council procedure, and local amendments touching residential buildings need Council approval.
Cycle. Triennial, following the ICC model-code cycle; 2021 edition effective Mar 15, 2024, 2024 edition targeted for May 3, 2027.
Laws, rulings, and other actions
- Other actionSBCC revises the 2024 code adoption schedule (latest revision dated Aug 14, 2026)
The revised schedule targets final adoption of the 2024 IBC, IRC and IFC on Oct 16, 2026, and of the 2024 energy codes on Nov 20, 2026, with a May 3, 2027, effective date; in 2025 the Council had sought to keep a Nov 1, 2026, implementation date (secondary source).
- LegislationSSB 55522025-26 sessions, chapter 41, Laws of 2026
Creates a kit-homes category of state building codes and instructs the Council to do rulemaking on the codes applicable to kit homes no later than Mar 31, 2027.
Enacted (chapter 41, Laws of 2026), effective Jun 11, 2026
lawfilesext.leg.wa.gov (opens in a new tab) - LegislationESSB 62912024 regular session, chapter 170, Laws of 2024
Restructures State Building Code Council procedure (amends RCW 19.27.031, .070, .074, 19.27A.025 and .045): one substantive update per three-year cycle, criteria and technical advisory groups for statewide amendments, and emergency amendments only on a two-thirds-approved Council finding.
Enacted Mar 18, 2024, effective Jun 6, 2024
lawfilesext.leg.wa.gov (opens in a new tab) - LegislationSB 61202024 regular session, chapter 133, Laws of 2024
Ties adoption of the Wildland Urban Interface Code to completion of statewide wildfire hazard and risk maps (RCW 19.27.560), so WAC 51-55 stays reserved with no state amendments; this is a separate code, not one of the six tracked slots.
Enacted Mar 15, 2024, effective Mar 15, 2024
lawfilesext.leg.wa.gov (opens in a new tab) - Other actionSBCC delays implementation of all 2021 codes to Mar 15, 2024
The Council voted to move implementation of the 2021 codes from Oct 29, 2023, to Mar 15, 2024 (as described in WSR 23-23-104); the final date is stated in WAC 51-50-008 and 51-51-008.
How it was checked
Verified
Two separate readings of the state’s own record agree, and the passage is on file word for word.
Read twice: a second, blind reading of the state’s record agreed with the first on .
The state’s record was last read on , from five source pages.
Evidence 5 sources
Sources for the record itself come first, the state’s own records ahead of others. A label marks a source about something else, such as an exception. A source marked secondary is not the state’s own record.
“The International Residential Code adopted by chapter 51-51 WAC shall become effective in all counties and cities of this state on”
“March 15, 2024.”
WSR 23-23-104 Permanent Rules, Building Code Council (chapter 51-51 WAC)Washington State Register (Office of the Code Reviser)lawfilesext.leg.wa.gov (opens in a new tab)State registerRetrieved “The 2021 edition of the International Residential Code as published by the International Code Council”
WAC 51-51-003 International Residential Code.Washington State Legislature (Office of the Code Reviser)app.leg.wa.gov (opens in a new tab)Administrative codeRetrieved “STATE BUILDING CODE ADOPTION AND AMENDMENT OF THE 2021 EDITION OF THE INTERNATIONAL RESIDENTIAL CODE”
Chapter 51-51 WACWashington State Legislature (Office of the Code Reviser)app.leg.wa.gov (opens in a new tab)Administrative codeRetrieved “2021 Code Editions and Amendments Effective March 15, 2024”
State Building Code Council home page (announcements)Washington State Building Code Councilsbcc.wa.gov (opens in a new tab)Agency pageRetrieved About an exception
“Approve or deny all county or city amendments to any code referred to in RCW 19.27.031 to the degree the amendments apply”
RCW 19.27.074Washington State Legislature (Office of the Code Reviser)app.leg.wa.gov (opens in a new tab)StatuteRetrieved