Washington building code

Codes in force in Washington

Each code family with the edition and the date it took effect, as the adopting agency or statute states them.

Scope, amendments and transition rules

International Building Code (IBC)

Scope

Statewide minimum; local governments may go further²

Applies to

All counties and cities²

Local amendments allowed?

Yes not below state minimum; residential amendments need SBCC approval²

Amendments

Chapter 51-50 WAC¹

Next edition (not yet in force)

2024 edition planned; implementation date Monday, May 3, 2027 (schedule, not yet adopted)⁶

International Residential Code (IRC)

Scope

Statewide minimum; local governments may go further²

Applies to

All counties and cities²

Local amendments allowed?

Only with State Building Code Council approval²

Amendments

Chapter 51-51 WAC¹

Next edition (not yet in force)

2024 edition planned; implementation date Monday, May 3, 2027 (schedule, not yet adopted)⁶

International Existing Building Code (IEBC)

Scope

Statewide minimum; local governments may go further²

Applies to

All counties and cities²

Local amendments allowed?

Yes not below state minimum; residential amendments need SBCC approval²

Amendments

Chapter 51-50 WAC, sections 51-50-480000 to 51-50-48xxxx¹

Next edition (not yet in force)

2024 edition planned; implementation date Monday, May 3, 2027 (schedule, not yet adopted)⁶

International Mechanical Code (IMC)

Scope

Statewide minimum; local governments may go further²

Applies to

All counties and cities²

Local amendments allowed?

Yes not below state minimum; residential amendments need SBCC approval²

Amendments

Chapter 51-52 WAC¹

Next edition (not yet in force)

2024 edition planned; implementation date Monday, May 3, 2027 (schedule, not yet adopted)⁶

International Fuel Gas Code (IFGC)

Scope

Statewide minimum; local governments may go further²

Applies to

All counties and cities²

Local amendments allowed?

Yes not below state minimum; residential amendments need SBCC approval²

Amendments

Chapter 51-52 WAC (sections 51-52-21000 and following)¹

Next edition (not yet in force)

2024 edition planned; implementation date Monday, May 3, 2027 (schedule, not yet adopted)⁶

International Fire Code (IFC)

Scope

Statewide minimum; local governments may go further²

Applies to

All counties and cities²

Local amendments allowed?

Yes not below state minimum; residential amendments need SBCC approval²

Amendments

Chapter 51-54A WAC¹

Next edition (not yet in force)

2024 edition planned; implementation date Monday, May 3, 2027 (schedule, not yet adopted)⁶

Uniform Plumbing Code (UPC)

Scope

Statewide minimum; local governments may go further²

Applies to

All counties and cities²

Local amendments allowed?

Yes not below state minimum; residential amendments need SBCC approval²

Amendments

Chapter 51-56 WAC¹

Next edition (not yet in force)

2024 edition planned; implementation date Monday, May 3, 2027 (schedule, not yet adopted)⁶

Energy code, residential

Scope

Statewide; applies everywhere¹

Applies to

Residential buildings in every town, city and county¹

Local amendments allowed?

No (maximum and minimum code)¹

Amendments

Chapter 51-11R WAC¹

Next edition (not yet in force)

2024 edition planned; implementation date Monday, May 3, 2027 (schedule, not yet adopted)⁶

Energy code, commercial

Applies to

Commercial buildings¹

Amendments

Chapter 51-11C WAC¹

Next edition (not yet in force)

2024 edition planned; implementation date Monday, May 3, 2027 (schedule, not yet adopted)⁶

National Electrical Code (NEC)

Applies to

Statewide; L&I permits and inspects except in cities with their own electrical program and Tacoma Power's service area⁴

Amendments

Chapter 296-46B WAC¹

Transition period

Code edition follows electrical permit issue date; new dwellings follow building permit issue date¹

Next edition (not yet in force)

2026 NEC effective December 31, 2026¹

Wildland-Urban Interface Code (IWUIC)

Scope

Adopted locally²

Applies to

Counties, cities and towns that adopt it⁵

Amendments

Chapter 51-55 WAC (reserved)⁵

How Washington adopts building codes

RCW 19.27.031, 19.27.040, 19.27.050, 19.27.060, 19.27.074, 19.27.090

• Statewide state building code in effect in all counties and cities. Except as otherwise provided in this chapter, there shall be in effect in all counties and cities the state building code which shall consist of the following model codes which are hereby adopted by reference…²
• Model codes: IBC, IRC, IMC, IFC, limited IWUIC, UPC. (a)(i) The International Building Code, published by the International Code Council, Inc.²
• Three-year adoption cycle. (3)(a) The model codes enumerated in this section shall be adopted or amended by the council as provided in RCW 19.27.074 and 19.27.032 through 19.27.034 in a three-year state building code adoption cycle.²
• Council action within 30 months of model code publication. (b) The council shall review the most recent editions of each of the model codes enumerated in subsection (1) of this section and take action on adoption no later than 30 months after the date of publication of each such code.²
• Cycle decisions before December 1, effective after next regular legislative session. (c) All decisions to adopt or amend codes of statewide application through a three-year code adoption cycle shall be made prior to December 1st of any year and shall not take effect before the end of the regular legislative session in the next year.²
• State Building Code Council adopts and maintains the codes. (a) Adopt and maintain the codes to which reference is made in RCW 19.27.031 in a status which is consistent with the state's interest as set forth in RCW 19.27.020.²
• Council sits in the Department of Enterprise Services. There is hereby established in the department of enterprise services a state building code council, to be appointed by the governor.²
• Counties and cities enforce the code. The state building code required by this chapter shall be enforced by the counties and cities.²
• Local amendments allowed, may not diminish minimum standards. The governing body of each county or city is authorized to amend the state building code as it applies within the jurisdiction of the county or city. The minimum performance standards of the codes and the objectives enumerated in RCW 19.27.020 shall not be diminished by any county or city amendments.²
• Residential amendments need council approval. (a) Except as provided in subsection (2) of this section, no amendment to a code enumerated in RCW 19.27.031 as amended and adopted by the state building code council that affects single-family or multifamily residential buildings shall be effective unless the amendment is approved by the building code council under RCW 19.27.074(1)(b).²
• Zoning, setbacks, snow and wind loads reserved to local jurisdictions. Local land use and zoning requirements, building setbacks, side and rear-yard requirements, site development, property line requirements, requirements adopted by counties or cities pursuant to chapter 58.17 RCW, snow load requirements, wind load requirements, and local fire zones are specifically reserved to local jurisdictions notwithstanding any other provision of this chapter.²
• Permit application vests under code in effect at application. (1) A valid and fully complete building permit application for a structure, that is permitted under the zoning or other land use control ordinances in effect on the date of the application shall be considered under the building permit ordinance in effect at the time of application, and the zoning or other land use control ordinances in effect on the date of application.²
• International Residential Code (chapter 51-51 WAC) effective in all counties and cities on March 15, 2024. The International Residential Code adopted by chapter 51-51 WAC shall become effective in all counties and cities of this state on March 15, 2024.¹
• 2024 edition planned; implementation date Monday, May 3, 2027 (schedule, not yet adopted). Implementation Date Monday, May 3, 2027…⁶
• Electrical code adopted separately by L&I (2023 NEC). The 2023 edition of the National Electrical Code (NFPA 70 - 2023) including Annex A, B, C, and subsequent Errata and Tentative Interim Amendments issued by the National Fire Protection Association…¹

Applies to

All counties and cities²

Can local rules be stricter?

The governing body of each county or city is authorized to amend the state building code as it applies within the jurisdiction of the county or city. The minimum performance standards of the codes and the objectives enumerated in RCW 19.27.020 shall not be diminished by any county or city amendments.²

Residential code in Washington cities

The edition each city enforces, from the city’s own adoption page or ordinance.

For permits, exemptions and owner-builder rules, see Washington building permits. To compare editions across states, see the code adoption map.