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DID YOU KNOW?

In 1936, King County undertook a major property survey, the King County Land Use Survey, which was financed by the federal Works Progress Administration (WPA). The project greatly added to the county's tax base, and left an amazing record of buildings in King County.

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About Us


The King County Assessor's office dates back to the mid-1800's when Washington was still a territory. Today, the office of Assessor John Wilson handles assessments of more than 660,000 residential and commercial parcels in King County valued at $340.6 billion in 2013.

King County voters directly elect the King County Assessor to regular four-year terms. John Wilson was elected in November 2015 as the 38th King County Assessor.

The assessor's office employs more than 200 people covering all of King County, including highly skilled certified residential and commercial appraisers who regularly evaluate parcels throughout the county.

Our staff uses a variety of methods to establish property values, including on-site inspections, comparable sales of similar properties, comparisons of select properties and evaluation of other data, such as income for commercial properties.

Over the decades, the King County Assessor's office has become a remarkable repository of bits and pieces of the region's history. Pictures, most of which are now located in the State Archives, show initial construction of virtually every home and building in King County. Massive hand-written ledgers carry the property tax rolls from the turn of the 20th Century.

Today, the assessor's staff uses a variety of tools — detailed maps (both in paper and electronic), Tablet PCs to record and upload data, digital cameras to take a current snapshot of your property, and even an old fashion measuring tape. In 2011, the International Association of Assessing Officers (IAAO) awarded its best jurisdiction award to the King County Assessor's Office. This award is conferred on a national, state/provincial, regional or local assessment agency that has instituted a technical, procedural or administrative program that is, for the affected jurisdiction, an improvement over prior programs, and is generally recognized as a component of a model assessment system and a contributing factor to equity in property taxation.

It's all in dedication to our taxpayers to conduct our work in a fair, equitable and understandable manner.