Beginning January 1, 2028, Washington will impose a new individual income tax on high-income taxpayers. The tax applies at a rate of 9.9% to the Washington taxable income of each individual or couple exceeding $1 million, with the $1 million threshold generally serving as a standard deduction and subject to future inflation adjustments. The tax is imposed only on individuals and is based on a modified version of federal adjusted gross income, with various additions, deductions, and Washington-specific sourcing rules. The law will face litigation as to its constitutionality and a voter initiative to repeal the tax before it takes effect.
For Washington residents with substantial business, investment, trust, or pass-through entity income, early planning may become increasingly important as the 2028 effective date approaches.
For more information: Washington Income Tax