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Building and fire codes

For information on King County Building and Fire Codes, International Building Codes, and Washington State Building Codes. 

Every three years the International Building Codes are updated. King County is currently enforcing the 2018 International Building Codes. The Washington State Building Code Council has completed rule making that adopts and modifies the 2021 International Building Codes. That group of codes includes the building, residential, fire, energy, mechanical, and other codes, and makes up the “State Building Code”.

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2021 State Building Code effective March 15, 2024

All new permit applications received on or after March 15th, 2024,
must comply with the 2021 State Building Codes.

Residential Basics Program

The upcoming code change means the Registered Plans reviewed and approved under the 2018 State Building Codes will expire March 14th, 2024. The County has begun accepting applications for new Registered Plans based on the 2021 code as of January 16th, 2024. During the transition period (from January to March 2024), Basic permits may be issued for projects based on either the 2018 or 2021 registered plans.

2018 New building codes

Starting February 1, 2021 the Washington State’s 2018 International Building Codes became effective. All permit applications received and deemed complete on or after that date shall comply with those codes.

Sprinkler system

If property owners are preparing to submit building plans for a residential building permit, you need to determine if there is a need to install an automatic fire sprinkler system. A separate permit is required before installing a sprinkler system.

Application information

Fire permits, sprinkler systems for residential and commercial

Wildland Urban Interface (WUI) Code Updates

The International Wildland-Urban Interface Code (often referred to as “WUI”) is aimed at reducing wildfire risks to people and property. Changes to code have been approved at the state level that will impact construction in King County of buildings and structures where permit applications are deemed complete after the implementation date, currently set for March 15, 2024.

Implementation date note: The initial implementation date was July 1, 2023. However, the State Building Code Council (SBCC) has voted twice, on May 24, 2023, and September 15, 2023, to delay the implementation of the 2021 Washington State Building Codes. The current implementation date is now March 15, 2024.

Background and general requirements

The Washington State Legislature has adopted the 2021 International Code Council (ICC) codes. The Wildland-Urban Interface Code is part of this code. Beginning on March 15, 2024, projects not currently vested must meet these code requirements, which could have a significant impact on proposed construction.

The WUI code adds fire protection standards to all structures based on proximity to areas with "vegetative fuels" that can contribute to wildfires even if permits are not required. The WUI code specifies requirements for 1) driveway access to buildings and structures, 2) ignition-resistant construction requirements for buildings and structures, including decks, and 3) creation and maintenance of defensible space around buildings.

Where does this apply?

Determining if a property a project will have to comply with requirements of the WUI code can be done by consulting the WA Department of Natural Resources Map or by consulting the King County iMap and navigating to the Wildland Urban Interface layer under the Planning layer group.


Resources and links