OLYMPIA — After a grinding 25-hour floor debate that stretched through the night, the Washington State House of Representatives passed a landmark income tax bill on March 10, approving a 9.9 percent tax on household income exceeding $1 million per year. The bill passed 52–46 and now returns to the Senate for concurrence before heading to Gov. Bob Ferguson, who has pledged to sign it.
The legislation, Senate Bill 6346, marks the closest Washington has come to enacting a broad income tax in nearly a century. Proponents estimate it will generate between $3.4 and $3.7 billion annually, with revenue directed toward expanding the Working Families Tax Credit, reducing business-and-occupation taxes for small businesses, and bolstering K–12 education funding.
Supporters say the tax is a long-overdue fix to Washington’s notoriously regressive tax structure, which has historically placed a heavier relative burden on low- and middle-income residents. House Finance Chair April Berg, D-Mill Creek, celebrated the vote alongside Gov. Ferguson, framing it as a step toward a fairer system. Ferguson has emphasized that the revenue must be used to return money to working families “most impacted by our unequal tax system.”
Critics argue the bill is both unconstitutional and economically dangerous. Republicans contend that under a 1933 state Supreme Court ruling, income qualifies as property, making a graduated income tax a violation of the constitution’s uniform taxation requirement. Rep. Matt Marshall, R-Eatonville, warned that the measure signals a loss of public trust. “This is a dark day in Washington’s history,” he said.
Opponents also raised concerns about a slippery slope. Although a provision was added to prevent the tax from ever applying to households earning less than $1 million, skeptics fear future legislatures could lower the threshold. Some high-earning residents have already taken notice: former Starbucks CEO Howard Schultz announced plans to relocate to Florida amid the debate.
Legal challenges are expected. The bill is structured as a levy on the receipt of income, similar to Washington’s capital gains tax, which survived a constitutional challenge before the state Supreme Court in 2023. Absent judicial or voter intervention, the tax would take effect January 1, 2028, with initial returns due in 2029.
Washington would join Massachusetts, Minnesota, and several other states that have moved to impose additional taxes on high earners in recent years.