Washington’s new millionaires’ tax, established by Senate Bill 6346, is a 9.9% tax on individual adjusted gross income exceeding $1 million. It’s scheduled to take effect January 1, 2028, and applies only to individuals. The bill also amends a temporary 0.5% B&O surcharge on high-grossing businesses with income above $250 million.
The law may face legal challenges; if invalidated, other tax changes created by SB 6346 would be null and void.
If the law takes effect, beginning January 1, 2029, Washington will exempt certain essential goods from sales and use tax:
- Diapers for all ages
- Grooming and hygiene products like soap, shampoo, and toothpaste
- Qualifying over-the-counter drugs
These exemptions are intended to reduce the tax burden on everyday necessities. However, if the millionaires’ income tax is invalidated, the sales tax exemptions will be null and void.
SB 6346 removes sales and use tax on several B2B services that became taxable in 2025, including:
- Custom software and website development
- IT training services
- Security and investigation services
- Temporary staffing and certain live presentations
These changes, which will take effect January 1, 2029, aim to clarify and reduce complexity introduced by prior legislation (ESSB 5814). Businesses may still need to manage exemption certificates and documentation to support compliance.
Washington is not currently an income tax state, but Senate Bill 6346 introduces new taxes on high earners: a 9.9% tax on individual income above $1 million starting in 2028.
However, Washington’s new income tax is expected to face legal challenges due to the state constitution. If the bill becomes law and courts invalidate the income tax, related provisions — including sales tax exemptions — would be null and void.
Businesses should review taxability of products and services, update systems for upcoming exemptions, and monitor legal developments tied to SB 6346. Maintaining accurate exemption documentation is also important. Given ongoing changes, automation can help businesses apply correct tax treatment and stay aligned with evolving Washington tax rules.