State law requires that we appraise all property at 100% of its true and fair market value, according to the highest and best use of the property. This standard applies to residential as well as commercial property. While comparable sales are used primarily to determine market value of residential property, sales in combination with the income and cost approach is used by county assessors to value commercial property. WAC 458-07-030
A single-property appraisal is very time intensive, expensive, and not practical for the number of properties that we must appraise in a year. Therefore, we use mass appraisal techniques. The steps involved in mass appraisal are:
- Verify property characteristics
- Collect market data
- Analyze data
- Specify model
- Calibrate models
- Test the results
- Review the assessments
