On September 15, 2023, and for the second time, the State Building Code Council voted to delay the effective date of the 2021 Washington State Construction Codes. The new effective date will be March 15, 2024 (previous effective dates were July 1, 2023, and October 29, 2023). This additional time was needed for Council to enter rulemaking procedures to modify certain sections of the commercial and residential energy codes to address legal uncertainties stemming from the decision recently issued by the Ninth Circuit Court of Appeals in California Restaurant Association v. City of Berkeley.


Significant code changes for the 2021 code adoption cycle can be found here.


2021 International Building Code - WAC 51-50

2021 International Mechanical Code - WAC 51-52

2021 International Fire Code - WAC 51-54A

2021 Uniform Plumbing Code WAC 51 –56 and WAC 51-57

2021 International Fuel Gas Code - WAC 51-52

2020 Liquefied Petroleum Gas Code (NFPA 58) 

2021 International Property Maintenance Code

2021 International Residential Code - WAC 51-51

2021 Washington State Energy Code - WAC 51-11C and WAC 51-11R

2021 International Existing Building Code - WAC 51-50

2021 International Swimming Pool and Spa Code – WAC 51-50-3109

2021 International Wildland-Urban Interface Code – WAC 51-55

2017 ICC A117.1 Accessible and Usable Building and Facilities – WAC 51-50-005


The Construction Administrative Code regulates the above noted codes by adopting a uniform administrative code replacing Chapter 1 in each model code and can be found in NMC 15.05.

The City of Newcastle adopts City of Bellevue amendments to the IBC and IFC. These documents will be published with the final editions are available.

Snow loads are locally amended. Per NMC 15.10.020, IBC Section 1608.1 is amended. A snow load of not less than 25 psf is required; however, higher snow loads will apply at higher elevations, typically starting at an elevation of 500 feet. The City clarifies these provisions and applies the formula used in King County for calculating snow loads.

IRC R301.2 Climatic and Geographic Design Criteria has been completed and is available here.


Permit Applications accepted March 15, 2024, or later will be regulated under the 2021 Construction Codes. 

Deferred submittals that apply to a building permit regulated under the 2018 codes may be designed under the applicable 2018 codes. 

Plan review fees on any permit application accepted prior to March 15, 2024, intended to apply the 2018 codes must be paid within 3 days of invoicing.


The following resources are available for information on training:


Residential Energy Code

Commercial Energy Code

IAPMO/UPC Plumbing Code


The Washington State Amendments to the 2021 Construction Codes can be found here.

View the State Building Code Council's site.


Along with the typical I-Codes that the state adopts is a new code, the 2021 International Wildland-Urban Interface Code, which is significantly amended by the State of Washington (entitled the 2021 Washington State Wildland-Urban Interface Code). We call this the WUI Code for short.

The Washington State Department of Natural Resources (DNR) provided the mapping. Buildings and structures in the mapped WUI-Interface, WUI-Intermix, and Vegetated Uninhabited areas must comply with the specific provisions of the WUI Code. Applicants do have the option to submit a “findings of fact” per Appendix E of the WUI Code to the jurisdiction if they can provide justification that the mapping is incorrect. Otherwise, the specific construction standards will need to be applied to the project. There are prescriptive materials included in the WUI Code to make product selection easier.

The 2021 Washington State Wildland-Urban Interface Code, the base code plus state amendments, is available for viewing on the ICC website.  You can look up any parcel on the King County iMap to see if it is mapped as an interface/intermix area. Simply open the Layer List, check off the Planning layer, then expand the Planning layer and check off Wildland urban interface area. The mottled yellow hatched area is Wildland-Urban Interface.

The DNR has some background information on the purpose of the WUI Code, which you can view here. The WABO website has some additional resources including a WUI Flyer. The California Department of Forestry and Fire Protection Office of the State Fire Marshal has a publication that includes listed WUI products. 

We recommend that designers review all code requirements prior to submitting for permit. Education and training on this code is ongoing. You can check training events from multiple websites including WABO,, ICC, BIAW, AIA, WSFM, etc.


Free online access to base model codes is available online through ICC. Please note that the state-amended versions are available in online and printed editions of the IBC, IRC, IFC, WSEC, IMC, IEBC, and WUI.

The City of Bellevue provides access to their codes online. The City of Newcastle adopts most of the local amendments to the IBC and IFC. The documents available online include local and state amendments.

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