Assessment Standards

Thurston County employs a mass appraisal process to value properties as of a given date using standard methodology, employing common data, and allowing for statistical testing.

Property assessments are made to comply with both the appropriate Uniform Standards of Professional Appraisal Practice (USPAP) as published by the Appraisal Standards Board of The Appraisal Foundation, and other standards adopted by the International Association of Assessing Officers. In addition, Washington’s Assessors are directed by rules and regulations contained within the Revised Code of Washington.

For more information about these rules or organizations, please click the following:

Revised Code of Washington (Title 84)

The Appraisal Foundation

International Association of Assessing Officers