The Washington Supreme Court strikes down the Washington natural gas law Initiative 2066
The Washington Supreme Court ruled 6 to 3 on September 17, 2026, that Initiative 2066, the Washington natural gas law approved by voters in November 2024, is unconstitutional in its entirety. The case is Climate Solutions and other plaintiffs against the State of Washington. Chief Justice Debra Stephens wrote the ruling for the 6 justice majority. Initiative 2066 had barred the Washington State Building Code Council, the state body that writes construction rules, from amending the Washington State Energy Code, the rules that set how new buildings use energy, in any way that would discourage the use of gas for heating or other equipment, and from keeping a code goal of zero fossil fuel greenhouse gas emission homes and buildings by 2031. That legal bar no longer exists.
What Initiative 2066 changed before the ruling
Voters approved Initiative 2066 with 51.7% of the statewide vote in November 2024, according to the Spokesman Review. The measure ran 21 pages across 13 sections. It told the Building Code Council it could not adopt any rule that prohibits, penalizes, or discourages gas for heating, appliances, or equipment, and it removed the energy code own goal of zero fossil fuel greenhouse gas emission construction by 2031. A King County Superior Court judge struck the measure down in March 2025. The State of Washington, joined by the Building Industry Association of Washington, appealed that loss to the Supreme Court and lost again.
The 48.3% figure is this article own subtraction from the 51.7% figure the Spokesman Review reports, not a number either source states directly.
Show the numbers
| Voted for Initiative 2066 | 51.7 |
| Voted against Initiative 2066 | 48.3 |
The single subject rule that voided the Washington natural gas law
The court did not rule on gas heating policy itself. It ruled that Initiative 2066 broke the single subject rule in the Washington Constitution, article 2, section 19, which requires that 1 law cover only 1 subject so voters are not forced to accept an unrelated provision to get the 1 they actually want. The court opinion itself, read in full for this article, lists 4 distinct subjects Initiative 2066 packaged into 1 measure, requiring statewide natural gas access, limiting local authority over air quality, amending statewide building and energy codes, and repealing part of a separate 2024 law, the Washington Decarbonization Act for Large Combination Utilities. Because the majority found those 4 pieces could not be separated from each other, it voided the entire measure rather than saving any 1 part.
Because the provisions that introduce distinct subjects are not severable, I-2066 is unconstitutional in its entirety.
Chief Justice Debra Stephens, writing for the majority of the Washington Supreme Court. Source 1.
Show the numbers
| Justices who voted to void Initiative 2066 | 6 |
| Justices who voted to uphold Initiative 2066 | 3 |
What changes now for the Washington building code
The Washington State Building Code Council says on its own site that the current 2021 energy code stays in force until the Council itself adopts a change, so no new requirement exists yet for anyone building a home in Washington today. What is different is that the legal bar stopping the Council from writing a rule that favors electric heating over gas is gone, just under 2 years after Initiative 2066 first passed in November 2024, a span this article counts from that vote to the September 17, 2026 ruling. The Building Industry Association of Washington, which helped place Initiative 2066 on the ballot and then defended it in court, said the loss overrides what voters decided.
Today's decision represents a direct rejection of the clearly expressed will of Washington voters.
Greg Lane, executive vice president of the Building Industry Association of Washington. Source 5.
Nearly 2 million Washington voters supported I-2066 because they understood what rising energy mandates mean.
Anthony Anton, president and chief executive of the Washington Hospitality Association. Source 5.