Assessment Procedures
How We Value Property
All real and personal property in Washington is taxed on 100 percent of its market value, also called true and fair value, unless the law provides an exemption. We revalue property every year and physically inspect each property at least once every six years.
Appraisers use three generally accepted approaches to value:
| Approach | How it works |
|---|---|
| Sales comparison | Compares a property to recent sales of similar properties. |
| Cost | Estimates what it would cost to replace the buildings new, less depreciation, plus the value of the land. |
| Income | Converts the net income a property can produce into a value, mainly for commercial property. |
Because we value every property in the county each year, we use mass appraisal: statistical models built from local sales and costs, tested against actual sales to make sure values are accurate and uniform. For most homes, sales of similar properties are the main guide. The income approach is used mainly for commercial property.
Uniformity and Equalization
The Washington State Constitution requires property taxes to be uniform within a taxing district (Article VII, section 1). Properties of the same value in the same district pay the same tax. The one exception is farm, timber, and open space land, which the Constitution allows to be valued on its current use instead of market value (Article VII, section 11).
The Department of Revenue sets the state property tax that supports public schools. Because counties revalue on different cycles, a county's assessed values may not equal 100 percent of market value. To keep the state school levy fair from county to county, the Department of Revenue equalizes each county's values to market value before the levy is spread.
The Constitution exempts property owned by the United States, the state, counties, school districts, and other public entities. The Legislature may exempt other property by general law. Major exemptions include business inventories, household goods and personal effects, churches, nonprofit hospitals, and private schools and colleges.
To see how we measure uniformity each year, visit Comparable Sales for our Vertical Equity Report and the Department of Revenue's appraisal performance studies.
