HB 2381 — Concerning performance-based building codes for low-rise residential buildings.

H-3178.1H-2835.1 SUBSTITUTE HOUSE BILL 2381 State of Washington 69th Legislature 2026 Regular Session By House Local Government (originally sponsored by Representatives Duerr, Bernbaum, Ramel, Reed, Parshley, and Kloba)Kloba READPrefiled FIRST01/09/26. TIME 01/27/26.

Read first time 01/12/26.

Referred to Committee on Local Government.

amendingcreating RCWa 19.27A.020;new section;

and adding a new section to chapter 19.27 RCW;RCW.

and creating a new section.

1 SHBHB 2381 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.

(1) The state building code council shall adopt, by rule, a mandatory appendix to the international building code as amended by Washington 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 codecode, as amended by Washington, section 202.

2 SHBHB 2381 (4) 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 codecode, as amended by Washington, 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-levelsystem- level metrics, to the extent practicable and consistent with existing statutory authority.

(7) TheFor statethe buildingpurposes code council shall adopt section R406 of thethis internationalsection, energy conservation code as part of the appendixfollowing pursuantdefinitions toapply: subsection (1) of this section.

(8) For the purposes of this section, the following definitions apply:

(b) "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 p.compliance to be demonstrated through engineering analysis, testing, certification, modeling, or other approved evaluation methods.

3A SHBperformance-based 2381code compliancemay toinclude beprescriptive demonstratedprovisions throughbut engineeringallows analysis,p. testing, certification, modeling, or other approved evaluation methods.

A3 performance-basedHB code2381 may include prescriptive provisions but allows alternative compliance pathways that achieve equivalent or superior performance.

Sec.

3.

RCW 19.27A.020 and 2025 c 1 s 6 (Initiative Measure No.

2066) are each amended to read as follows:

(1) The state building code council in the department of enterprise services shall adopt rules to be known as the Washington state energy code as part of the state building code.

(2) The council shall follow the legislature's standards set forth in this section to adopt rules to be known as the Washington state energy code.

The Washington state energy code shall be designed to:

(a) Construct increasingly energy efficient homes and buildings by the year 2031;

(b) Require new buildings to meet a certain level of energy efficiency, but allow flexibility in building design, construction, and heating equipment efficiencies within that framework;

((and)) (c) Allow space heating equipment efficiency to offset or substitute for building envelope thermal performance;

and (d) Allow demonstrated reductions in embodied carbon associated with building materials to offset or substitute for modeled operational energy use intensity requirements in performance-based compliance pathways applicable to buildings subject to the international building code as amended by Washington state.

(3) The Washington state energy code may not in any way prohibit, penalize, or discourage the use of gas for any form of heating, or for uses related to any appliance or equipment, in any building.

(4) The Washington state energy code shall take into account regional climatic conditions.

One climate zone includes:

Adams, Asotin, Benton, Chelan, Columbia, Douglas, Ferry, Franklin, Garfield, Grant, Kittitas, Klickitat, Lincoln, Okanogan, Pend Oreille, Skamania, Spokane, Stevens, Walla Walla, Whitman, and Yakima counties.

The other climate zone includes all other counties not listed in this subsection (4).

The assignment of a county to a climate zone may not be changed by adoption of a model code or rule.

Nothing in this section prohibits the council from adopting the same rules or standards for each climate zone.

p.

4 SHB 2381 (5) The Washington state energy code for residential buildings shall be the 2006 edition of the Washington state energy code, or as amended by rule by the council.

(6) The minimum state energy code for new nonresidential buildings shall be the Washington state energy code, 2006 edition, or as amended by the council by rule.

(7)(a) Except as provided in (b) of this subsection, the Washington state energy code for residential structures shall preempt the residential energy code of each city, town, and county in the state of Washington.

(b) The state energy code for residential structures does not preempt a city, town, or county's energy code for residential structures which exceeds the requirements of the state energy code and which was adopted by the city, town, or county prior to March 1, 1990.

Such cities, towns, or counties may not subsequently amend their energy code for residential structures to exceed the requirements adopted prior to March 1, 1990.