Oregon law says the assessor must value all property at 100 percent of its real market value. Real market value (RMV) is typically the price your property would sell for in a transaction between a willing buyer and a willing seller on January 1, the assessment date for the tax year. To estimate the initial RMV for your property, your county assessor appraises your property using a physical inspection and a comparison of market data from similar properties. For ensuing tax years, your county assessor may study trends of similar properties to update the RMV for your property. Some property, such as farm or forest property, may be subject to special valuation processes.

Each year, county assessors develop a new assessment and tax roll. From one year to the next, the major change between rolls is the property values. Change is the one constant in the value of real estate. Changes may be gradual and not easily noticed, or changes may occur rapidly in an active market. Because property values are always changing, assessors must update the RMV to keep them current with the market. The process for measuring these changes is called the ratio study. The assessor is required to create a ratio study annually (ORS 309.200).

Property is taxed on its assessed value (AV). A property's AV is the lower of its RMV or its maximum assessed value (MAV). Each year, the county assessor determines the property's RMV and calculates its MAV. You are taxed on the lesser of the two, which is called the assessed value (AV).

How to Become a Property Appraiser
Property Class Descriptions
Building Statistical Class Descriptions

Farm Forest Appraisal
Assessment of Farmland in an Exclusive Farm Use Zone
Assessment of Farmland Not in an Exclusive Farm-Use Zone
Specially Assessed Forestland