wa-law.org > bill > 2025-26 > HB 2381 > Original Bill
The legislature finds that Washington faces an ongoing shortage of low-rise residential buildings and that existing building code compliance pathways are largely prescriptive or applied on a project-by-project basis, increasing permitting uncertainty, limiting innovation, and constraining the ability to scale housing production. Performance-based building codes are effectively used nationally and internationally to address structural design, fire and life safety, egress, durability, and other core building functions, enabling repeatable approvals and industrialized housing delivery. Washington currently lacks a comparable, system-level performance-based compliance pathway under the international building code for low-rise residential buildings.
The legislature further finds that establishing a codified performance-based compliance pathway for low-rise residential buildings can reduce regulatory friction, improve permitting predictability, and support off-site manufacturing and industrialized construction. By allowing housing systems and building plans to demonstrate compliance based on measured performance rather than prescribed methods, such a pathway can enable reuse of approved designs across jurisdictions, support manufacturing at scale, and help reduce the cost of housing delivery while maintaining appropriate health, safety, and welfare protections.
The legislature additionally finds that a unified performance-based approach can provide a foundation for aligning building code compliance with existing performance-based energy efficiency and emissions programs, including opportunities to streamline energy code compliance and integrate operational energy efficiency and whole life carbon considerations, including embodied carbon.
It is therefore the objective of the legislature to facilitate increased housing production and predictability by directing the development of a state-approved performance-based housing system and plan certification pathway for low-rise residential buildings.
The state building code council shall adopt, by rule, a mandatory appendix to the international building code to establish a performance-based code compliance pathway for low-rise residential buildings with residential occupancy. The appendix shall apply to buildings of one to six stories above grade plane that are not classified as high-rise buildings under international building code, section 202.
In developing the appendix required under subsection (1) of this section, the council shall convene a technical advisory group for the purpose of recommending performance-based code amendments. The advisory group shall include subject matter experts and appropriate state agencies, including the department of labor and industries, the department of commerce, the University of Washington, and Washington State University.
The advisory group shall develop and recommend performance criteria categories and targets for building systems, subsystems, components, products, and materials. In developing its recommendations, the advisory group shall consider existing and emerging nationally recognized standards and certification frameworks, including system-level housing performance and certification efforts developed or sponsored by the national institute of building sciences.
In adopting rules under this section, the council shall ensure that the performance-based compliance pathway supports integrated and harmonized compliance across the international building code, the Washington state energy codes, and rules addressing building-related greenhouse gas emissions, including both operational energy emissions and emissions associated with building materials. The council shall provide for a performance-based approach that allows coordinated compliance using whole-building or system-level metrics, to the extent practicable and consistent with existing statutory authority. The approach shall function as an alternative to separate prescriptive compliance pathways otherwise applicable and shall avoid duplicative compliance submittals and reviews.
The council shall adopt rules establishing criteria under which housing systems and plan certifications issued by independent, nationally recognized third-party evaluation or certification organizations may be recognized for purposes of demonstrating compliance with the state building code. A housing system or plan certification recognized under this section shall be deemed to demonstrate compliance with the applicable provisions of the state building code and shall be accepted by local authorities having jurisdiction for purposes of permit review and inspection within the scope of the certification.
The advisory group shall provide its recommendations to the council in time for the council to adopt or amend rules and codes as necessary for implementation in the first substantive code update to the state building code, as provided for in RCW 19.27.031 and 19.27.032, occurring after January 1, 2027.
For the purposes of this section, the following definitions apply:
"Low-rise residential building" means a building with residential occupancy containing from one to 24 dwelling units, including detached, attached, stacked, or clustered housing types.
"Performance-based code" means a regulatory framework that establishes measurable performance objectives for buildings, building systems, or building elements, without prescribing specific materials, assemblies, or construction methods, and that allows compliance to be demonstrated through engineering analysis, testing, certification, modeling, or other approved evaluation methods. A performance-based code may include prescriptive provisions but allows alternative compliance pathways that achieve equivalent or superior performance.