The King County Assessor’s office has begun mailing annual property valuation notices, revealing a notable shift after years of aggressive growth. Preliminary data indicates that upward market pressure eased throughout 2025, leading to flat or lowering residential values across much of the region.
Residential Market Cooling
The cooling trend is most pronounced in Eastside markets, which are seeing the county's largest value reductions following years of rapid appreciation. In Seattle and southern parts of the county, residential values have either remained flat or declined by up to 5%. Some Eastside neighborhoods have experienced even steeper drops, with valuations falling by as much as 10%. Chief Deputy Assessor Al Dams noted that this transition reflects a broader trend occurring both across Washington and the rest of the country.
Commercial Sector Trends
While the broader commercial market in King County remains stable, Seattle’s central business district is facing significant challenges. High vacancy rates in major office towers have driven values down between 5% and 20%. Despite these dramatic shifts in the downtown skyline, the Assessor’s office emphasized that these office buildings constitute only a small portion of the overall commercial sector.
Understanding the Tax Impact
It is important for taxpayers to distinguish between property values and tax obligations. The total property tax collected is determined by budgets passed by state, county, and local governments, as well as voter-approved levies. Because the decline in Seattle office values is concentrated in one sector, it is not expected to result in an appreciable tax increase for the vast majority of King County property owners. Voter-approved levies continue to have a more significant impact on tax increases than fluctuations in property values.
Timeline and Next Steps
The current valuation process sets property values as of January 1, 2026. These assessed values will be applied to the tax bills due in 2027. Although the valuation process is still ongoing for some areas, the Assessor’s office is moving forward with mailing notices to keep taxpayers informed of these changing market conditions
