What the Law Does.
that triggers the tax
above the threshold
the court and the ballot
Key takeaways
What to remember.
The law taxes Washington State residents at 9.9% on household income over $1 million a year, combining ordinary wages, restricted stock units, and capital gains into one aggregate figure.
This is law. Governor Ferguson signed SB 6346 on March 30, 2026, making it Washington State's first income tax since 1932. Whether it survives long enough to actually collect anything is a separate question.
Washington State's constitution has treated income as property since the 1930s, and property must be taxed the same way across the board. A graduated tax has historically failed that test, and a coalition led by former Attorney General Rob McKenna sued within two weeks of the signing to make exactly that argument.
The law doesn't take effect until January 1, 2028, with the first payments due in 2029. That's a multi-year runway, and families who use it to plan tend to land in a better position than families who wait for a final answer that may never fully arrive.
Changing domicile is the primary way to avoid the tax, but it's judged on facts and circumstances: banking, medical care, mailing address, driver's license, voter registration, and time actually spent in the state.
Two separate fights could still undo it: a constitutional lawsuit in Klickitat County Superior Court, and Initiative 645, a November 2026 ballot measure that would repeal the tax outright. Neither is resolved.