I-645: Washington Income Tax Repeal

Washington voters will decide in November 2026 whether to repeal the state’s new individual income tax before collections begin.

Initiative 645 would repeal the 9.9% tax on Washington household income over $1 million, scheduled to take effect January 1, 2028. It would also prohibit state and local governments from imposing taxes on individual income.

The Washington Research Council estimates that I-645 would reduce revenues to funds subject to the state budget outlook by $3.108 billion in 2027–29 and $8.324 billion in 2029–31. However, the Council notes that the tax has not yet been collected, taxpayer responses remain uncertain, and income-tax revenue can be volatile.

The brief also examines how the initiative would interact with tax-relief provisions adopted under ESSB 6346, Washington’s ongoing budget challenges, the constitutional challenge to the income tax, and possible legal questions involving the state capital gains tax.

Members can read the full policy brief for a detailed, fact-based overview of the initiative and the fiscal questions facing Washington policymakers.

Related Links: I-645: Repealing the State Individual Income Tax