Property values are climbing all over King County: up 22% over last year in Black Diamond, 18% in Woodinville and 13% in Skyway.

But if you live in those areas, that doesn’t necessarily mean your property taxes are going to skyrocket by the same amount.

The King County Assessor’s Office has begun sending out property valuation notices for this year, which will be used to set next year’s property taxes.

However, because of the way Washington calculates property taxes, a spike in property values doesn’t always mean an equivalent spike in property taxes. Instead, new levies and tax measures have a more dramatic effect on tax bills, according to the assessor’s office. This year, for example, property owners in several areas of South King County saw double-digit tax increases in part due to voter-approved levies. 

This year’s rising values are driven by the area’s hot housing market, where high demand and low supply are driving bidding wars and high prices.

Property values are set in part by analyzing comparable sales. Median single-family home prices in King County last month were up 10% from a month earlier and 14.5% over last year. Prices have climbed most dramatically outside Seattle in areas that are more affordable or offer more space.


The assessor’s office is still reviewing properties inside the city of Seattle but expects that “much of the city will be in the single-digit range” for growth in value, Assessor John Wilson said Thursday. 

That includes West Seattle, where Wilson said the bridge closure had a “significant impact on people’s willingness to sell houses, people’s willingness to buy houses.” 

“But early in the pandemic,” Wilson added, “I heard from a number of homeowners who were concerned this was going to crush their home value, that it was going to plunge through the floor. That’s not been the case at all.”

Many commercial properties in King County will also be assessed at higher values this year despite the economic downturn, Wilson said.

“Generally speaking, even with the COVID restrictions, it hasn’t adversely affected the value of the land or the building structure on that land,” Wilson said.

Hard-hit sectors like hotels, parking garages and movie theaters are seeing some small drops in value, according to the assessor’s office, though a spokesperson said more detailed information won’t be available until later in the year.   


After receiving a valuation notice, property owners in King County can appeal if they disagree with the county’s assessment. 

For property taxes due this year, the county offers payment plans and other assistance programs for business owners and people who are 60 or older, retired because of a disability or who have low income. Visit the King County Treasury website or the King County Assessor website for more information.