No personal income tax through December 31, 2027
Washington does not impose a personal income tax on residents or nonresidents for tax years through December 31, 2027. The state has no individual income tax filing requirement, no withholding on wages, and no tax on wages, salaries, investment income, retirement distributions, or other forms of personal income during this period.
Source: Washington Department of Revenue – Income Tax
The absence of a personal income tax is codified in statute. RCW 1.90.100 (Initiative 2111, enacted in 2024) provides: "Neither the state nor any county, city, or other local jurisdiction in the state of Washington may tax any individual person on any form of personal income."
Source: RCW 1.90.100
Washington's constitutional prohibition on graduated income taxes stems from a 1933 state Supreme Court ruling in Culliton v. Chase, which held that income is property under the state constitution's uniformity clause, and therefore a graduated income tax violates the requirement that taxes on the same class of property be uniform. Voters have rejected income tax measures eleven times since 1932, most recently a 2010 ballot initiative (I-1098) that was defeated 64% to 36%.
New law enacted for 2028 and later
On March 30, 2026, Governor Bob Ferguson signed Engrossed Substitute Senate Bill 6346 into law. The bill amends RCW 1.90.100 to create an exception to the income-tax prohibition and establishes a 9.9% tax on household income exceeding $1 million per year, effective January 1, 2028. First tax returns and payments are due in April 2029 for the 2028 tax year.
Source: ESSB 6346, Chapter 238, Laws of 2026
The new tax applies to Washington residents' worldwide income and to nonresidents' Washington-source income. It starts with federal adjusted gross income, allows a $1 million standard deduction per household (not per individual), and permits credits for capital gains taxes paid to Washington, business and occupation taxes, and income taxes paid to other states. The $1 million threshold is indexed for inflation beginning in 2030.
Source: ESSB 6346 Enrolled Bill Text
Constitutional challenge pending
A lawsuit challenging ESSB 6346 on state constitutional uniformity grounds was filed in Klickitat County Superior Court on April 9, 2026. The litigation raises the same constitutional issue that invalidated Washington's 1933 graduated income tax. The case is at an early stage, and the outcome will determine whether the January 1, 2028 effective date survives judicial review.
Unable to confirm as of 2026-05-26.
Not yet human confirmed. This section addresses two distinct legal regimes separated by an effective date. The 2028 income tax statute exists but faces constitutional challenge. Practitioners should monitor litigation and await Department of Revenue implementing regulations before advising on 2028 and later years.
Annual return filing requirements and due dates for tax years 2028 and later
Taxpayers who owe Washington personal income tax must file an annual return on or before the filing date of their federal income tax return—April 15 for calendar-year taxpayers. Individuals who owe no tax are not required to file a return. The tax must be paid by electronic funds transfer or other forms of electronic payment authorized by the Department of Revenue; the department may waive the electronic payment requirement for good cause.
Source: ESSB 6346, § 301(1)–(3), Chapter 238, Laws of 2026
Estimated tax payments will be required under rules aligned with federal estimated tax payment requirements, but no estimated payments are required before July 1, 2029. Section 501 of ESSB 6346 imposes an underpayment penalty on taxpayers who fail to make sufficient estimated payments during the tax year; the penalty is calculated as interest on the shortfall. The Department of Revenue is authorized to establish payment schedules, safe harbor thresholds, and administrative procedures for estimated payments.
Source: ESSB 6346, § 501, Chapter 238, Laws of 2026
The first annual returns and first payments under the new tax are due in April 2029 for tax year 2028.
Not yet human confirmed. The Department of Revenue has not yet issued implementing regulations or administrative guidance on return forms, filing procedures, or estimated payment mechanics. Practitioners should monitor DOR rulemaking.
Tax rate and income threshold for 2028 and later years
Beginning January 1, 2028, Washington imposes a 9.9% tax on Washington taxable income exceeding $1,000,000 per household. The tax is applied only to income above the threshold; the first $1,000,000 of Washington taxable income is not taxed. The standard deduction is indexed for inflation beginning with tax year 2030.
Source: ESSB 6346, § 201 and § 316, Chapter 238, Laws of 2026
Calculation of Washington taxable income for 2028 and later years
Washington taxable income is calculated in two steps. First, the taxpayer starts with federal adjusted gross income (Internal Revenue Code § 62) and applies Washington-specific modifications in sections 302 through 313 of the act to arrive at "Washington base income." These modifications exclude long-term capital gains (§ 302), add back state and local income taxes and B&O and public utility taxes (§ 304), and adjust for other items including out-of-state municipal bond interest (§ 303) and charitable contributions (§ 309). Second, the taxpayer subtracts a $1,000,000 standard deduction per household (§ 314) to arrive at Washington taxable income.
Who qualifies as a Washington resident for tax years 2028 and later
An individual is a Washington resident under either of two tests. First, a person domiciled in Washington during the taxable year is a resident—unless all three conditions of the 30-day safe harbor are met: (1) no permanent place of abode in Washington during the entire year, (2) a permanent place of abode outside Washington for the entire year, and (3) 30 or fewer days of physical presence in Washington during the year. Second, even if not domiciled in Washington, an individual who maintains a place of abode in Washington and is physically present in the state for more than 183 days during the year is a resident.
Nonresident employment compensation sourcing and five-day safe harbor for 2028 and later years
Beginning January 1, 2028, nonresident individuals are subject to Washington personal income tax only on income derived from sources within Washington. For employment compensation, the general sourcing rule allocates wages and other compensation to Washington to the extent the services giving rise to that compensation are performed within the state, regardless of the employer's commercial domicile location.
Source: ESSB 6346, § 401(2)(a), Chapter 238, Laws of 2026
Day-count apportionment for multi-state employment
When a nonresident employee performs services both within and outside Washington, the compensation is apportioned based on the ratio of days worked in Washington to total days worked. The Department of Revenue may approve another reasonable apportionment method in appropriate circumstances.
Source: ESSB 6346, § 403(1), Chapter 238, Laws of 2026
Five-day de minimis safe harbor
A nonresident who performs services in Washington for five or fewer days cumulatively during a calendar year is not required to allocate any income from those services to Washington. This safe harbor does not apply to nonresident professional athletes, student athletes, or entertainers, who are subject to separate apportionment rules under sections 404 and 407 of the act.
Source: ESSB 6346, § 401(3), Chapter 238, Laws of 2026
No convenience-of-the-employer rule
Washington did not adopt a convenience-of-the-employer rule. A nonresident working remotely from another state for a Washington-based employer owes no Washington tax on compensation for services performed outside the state, even if the employee could have performed the work in Washington. Only services physically performed in Washington are sourced to the state under the statute.
The five-day threshold is measured on a calendar-year basis, not a tax-year basis. A nonresident who visits a Washington office for six days in a calendar year must allocate compensation for the days worked in Washington (subject to apportionment under section 403), but a nonresident who visits for five or fewer days reports zero Washington-source employment income for that year, regardless of total compensation level.
Not yet human confirmed. The Department of Revenue has not yet issued implementing regulations on apportionment methodology, day-count mechanics, or the interaction between the five-day safe harbor and the day-ratio apportionment rule. Practitioners advising nonresidents with Washington business travel should monitor DOR guidance.