In King County, fewer than 1% of homeowners appeal the assessed value of their property each year, which is used to distribute the tax burden. An analysis of data from 2021 to 2024 found that residents of the wealthiest areas do so particularly often. In Medina and Clyde Hill, homeowners filed appeals more than five times as often as residents of Seattle, Renton or Kent.
The highest share of appeals was recorded in Medina, Clyde Hill, Sammamish and Duvall. In the small enclave of Hunts Point, nearly 11% of homeowners filed appeals, although the high figure is partly explained by the small number of homes. Owners of properties valued at $2 million to $3 million filed appeals nearly eight times as often as owners of homes valued at $500,000 to $1 million.
The King County Assessor’s Office calculates each property’s estimated market value annually, as of Jan. 1 of the previous year. This amount does not necessarily match the price for which a home could be sold today; it is used primarily to distribute taxes among properties. The assessment is influenced by location, water or mountain views, the size and shape of the lot, the size and condition of the home, the number of rooms, the presence of a garage or outbuildings, renovations, zoning and the prices of comparable sales.
After receiving notice of a new assessment, a property owner has 60 days to file an appeal. Generally, the owner must show that the assessor made an error in the property’s characteristics or valued it above market value. Supporting evidence may include an independent appraisal, information about comparable sales, photographs, repair estimates and documents showing the home’s actual condition. High maintenance costs alone generally are not considered sufficient grounds for lowering an assessment.
Countywide, about one-quarter of applicants win their appeals on average. An appeal primarily challenges the assessed value, not a specific tax rate. If the assessment is lowered, the owner will generally pay less, but the amount saved depends on the combined rates imposed by the county, municipality, school district and other taxing authorities. As a result, the same reduction in assessed value in Medina, Clyde Hill, Seattle or another city may produce different savings. School levies make up a significant share of the tax, but they are not canceled separately during an appeal: The tax base to which the overall rate is applied is reduced. Special districts, annual charges and Washington state tax limits also affect the final amount.
At the same time, wealthier homeowners stand to save more because even a small reduction in the assessment of an expensive home can significantly reduce the tax burden. Features of high-end properties also influence the decision to appeal: Assessors may inaccurately evaluate views, proximity to water, lot size, complex layouts and the quality of renovations. In addition, a homeowner perceives an increase from $4 million to $4.5 million differently from an increase in a home’s value from $400,000 to $450,000.
Researchers have found similar patterns in other parts of the United States. In Miami-Dade County, homeowners in predominantly white and affluent neighborhoods were more likely to obtain assessment reductions. Researcher William Doerner said such residents may be more familiar with tax programs and have the time and resources to prepare documentation. Companies that help with appeals for a fee also tend to advertise their services more often in wealthy neighborhoods.
King County officials emphasize that everyone has the same right to appeal, and that property owners receive annual notices about the procedure. Applications can be filed through an online portal with a comparable-sales search tool. The Assessor’s Office provides free instructions, forms, property information and explanations of the process; those who need language assistance should request it in advance.
Older homeowners and people with low incomes can also check whether they qualify for Washington state property-tax exemption or reduction programs, although such programs do not replace an appeal based on an inflated assessment. Depending on the circumstances, free or low-cost legal assistance may be available from the Northwest Justice Project and local legal-aid centers. Interpreters may also be offered by government agencies, libraries and ethnic community organizations in the county.
Researchers believe that greater fairness requires free representatives who could help low-income, older and other property owners navigate the process. Without such support, the system is used primarily by people who already have the time, knowledge and financial resources.
Based on: In King County, who is more likely to appeal home values?