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King County personal property tax information

King County personal property tax information

All businesses in King County are required to file a personal property tax affidavit.

The King County Department of Assessments is responsible for assessing personal property used by a business. King County's Treasury Operations is responsible for mailing personal property tax statements and collecting the tax.

What is Personal Property?

Personal property typically includes items used by a company to conduct business. Generally, personal property does not include property which is attached to a building or to the land.

Examples of personal property which may be assessed include furniture, fixtures, electronic equipment, telephones and machinery.

How do I pay?

If you have a Washington State Business License external link with the State of Washington, as is required for all businesses operating in Washington State, you must contact the King Department of Assessments at 206-296-5126 or to report your new business. Businesses that do not self-report their personal property are subject to a penalty of up to 25 percent in the aggregate against the total tax liability by the Washington State Department of Revenue if they are discovered by the Assessor.

Based on the information provided, the assessed value of a company's personal property is determined, and a valuation notice is sent. The assessed value for the current year becomes the basis for taxes due the following year.

The County's Treasury Operations sends out personal property tax statements in mid-February. These statements are based on information from the Assessor's records. Payments are due on April 30th and October 31st.

Where can I get more information?

If you have questions about personal property tax valuation and process, please contact the King County Assessor's Office at 206-296-5126 or e-mail The Assessor's Office also provides Personal Property Assessment Forms and Business Personal Property Assessments information online.

If you have questions about the personal property tax payment, or if you did not receive your statement, please call Treasury Operations at 206-263-2844.

If you are purchasing an existing business, please call Treasury Operations at 206-263-2844 to inquire if any taxes are due.

For more information

The Department of Local Services, Permitting Division can address questions only about the types of business licenses that it issues (see list).

For general business license questions, you must contact Washington State Business Licensing at 1-800-451-7985.

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