A collection of home builders, gas utilities, and building trade unions sued the Washington State Building Code Council (“WSBCC”) over its new building codes, arguing that they violate the federal Energy Policy and Conservation Act (“EPCA”).


Buildings are one of the largest sources of greenhouse gas emissions in the United States. The combustion of natural gas also affects indoor air quality, emitting hazardous pollutants such as nitrogen dioxide, carbon monoxide, and benzene. It is understandable then that many state and local governments are seeking to curb emissions through building codes.


Washington State updated its residential and commercial building codes this year, as it does every three years based on the latest edition of the International Energy Conservation Code (“IECC”). The new codes were based on the 2021 IECC and became effective on March 15, 2024.

The WSBCC had worked on a previous version of the building code but put that version on hold to determine if any changes were needed to ensure EPCA compliance following the Ninth Circuit’s April 2023 decision in California Restaurant Association v. Berkeley. The previous code was also challenged by a similar coalition in a federal lawsuit filed in May 2023, but the plaintiffs voluntarily withdrew the lawsuit after the WSBCC reopened its proceedings on the building code.

Once the new codes were adopted, construction trade groups and others sued in Washington state court under state law claims regarding the WSBCC’s authority and procedure.1

A collection of home builders, gas utilities, and building trade unions also sued again in federal court under EPCA preemption claims. EPCA generally preempts state or local governments from enacting energy efficiency or energy use standards for covered products, like furnaces or water heaters.2 If a state or local building code would otherwise be preempted as an energy use or energy efficiency standard, there are seven criteria the code can meet to receive an exemption from preemption.3

In this lawsuit, the plaintiffs assert that the energy codes are covered by EPCA and do not meet the seven exemption factors. In particular, they claim that:

  • The code’s use of a heat pump in the standard reference design violates EPCA because heat pumps exceed the efficiency of EPCA-covered gas products
  • By assigning increased credits to heat pumps this violates EPCA’s “one to one equivalent energy use” requirement
  • The code “prohibits” the use of gas appliances “in many instances,” in violation of EPCA
  • The prescriptive pathway under the code is not eligible for EPCA exemptions
  • The “fossil fuel compliance path” fails to specify an energy consumption or conservation objective, and does not use specified test procedures as required by the EPCA exemption test
  • Even if EPCA’s exemptions would protect the code’s application to new buildings, the exemptions would not apply to appliance replacements or alterations


The case was filed on May 15, 2024 in the Western District of Washington and assigned to District Judge Kymberly Evanson.

The WSBCC will either file an answer to the complaint or move to dismiss the lawsuit by July 10. Assuming the WSBCC files a motion to dismiss, briefing on that motion is scheduled to be completed by August 30.

1 Nw. Reg’l Council of Nat’l Constr. et al vs. State Bldg. Code Council, Docket No. 23-2-00615-34 (Wa. Super. Ct. Feb 28, 2023). On May 28, 2024 this lawsuit was dismissed by the court without prejudice.

2 42 U.S.C. § 6297(c).

3 42 U.S.C. § 6297(f)(3).

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