What Washington DOR Says the Millionaires Tax Will Cost to Administer

What DOR clarified

The Washington Department of Revenue has published a fact check addressing public claims about the cost and staffing required to implement Senate Bill 6346. The 2026 legislation establishes an income tax on income over $1 million and also expands the Working Families Tax Credit (WFTC).

DOR’s central point is that figures describing the entire bill should not be treated as the cost of the income tax alone. The agency says implementation is a multiyear effort and that the fiscal note combines several distinct programs and expenses.

The $275 million figure includes more than the income tax

DOR estimates that administering the income tax will cost approximately $30 million per year once the tax is in effect. According to the agency, that amount includes employee costs, system operation and maintenance, monitoring, and additional support functions.

The much larger $275 million figure covers more than tax administration. It also includes the cost of expanding the WFTC program and more than $231 million in anticipated refunds to WFTC recipients. In other words, the broader fiscal-note total is not an annual operating-cost estimate for the income tax by itself.

How DOR explains the staffing numbers

DOR also distinguishes between staffing for the income tax and staffing for all work required by SB 6346:

• Approximately 130 employees are expected to administer and enforce the income tax.
• The often-cited figure of more than 300 employees covers the bill as a whole, not the income tax alone.
• DOR expects to add more than 100 WFTC employees because the expansion is projected to increase the eligible population from about 350,000 people to more than 800,000.

The agency says its 130-employee estimate is based on the law as written. DOR currently expects the tax to apply to potentially 21,000 taxpayers with income over $1 million; it says the staffing estimate does not assume that the tax will later be expanded to everyone.

What this means for taxpayers and advisers

This DOR publication is a clarification of the state’s implementation budget—not new filing guidance. It does not announce forms, filing procedures, deadlines, or a change to the tax threshold. Those details should be tracked separately as DOR continues implementing the law.

For tax professionals, controllers, and business owners, the practical takeaway is to keep the program costs separated when discussing the new law:

• Use the $30 million figure when referring to DOR’s estimate of annual income-tax administration costs.
• Treat the broader $275 million figure as a combined estimate that includes the WFTC expansion and refunds.
• Identify individuals who may be affected by the $1 million threshold and continue monitoring official DOR implementation guidance.
• Do not treat staffing estimates as evidence of a broader tax than the law DOR is currently implementing.

Bottom line

DOR’s explanation narrows two headline claims. The agency’s current estimate for the income tax itself is approximately $30 million a year and 130 employees. The higher cost and staffing figures reflect the wider scope of SB 6346, especially the expansion of the Working Families Tax Credit.

Official source

Read DOR’s full explanation of the implementation costs.

Need help?

Washington Tax Desk helps taxpayers and advisers evaluate Washington tax developments and turn new guidance into practical next steps. Contact info@washingtontaxdesk.com.