The Assessor is required to maintain 2 values for each parcel that is classified. The first is the value that would be placed on the land if it was not classified. This is commonly referred to as the "fair market value." The second is the current use land value based on its present use as classified by the granting authority. The process for determining the value of open space lands is spelled out in statute (RCW 84.34). The assessor shall consider only the use to which such property is currently applied and shall not consider potential uses of such property.
?Open space land located within a county that has established a public benefit rating system will be valued according to the criteria of the rating system. In absence of a rating system, the valuation will be no less than that for farm and agricultural land.
?In determining the current use value of farm and agricultural land the assessor shall consider the earning or productive capacity of comparable lands from crops grown most typically in the area averaged over not less than 5 years. This earning or productive capacity shall be the "net cash rental" and shall be capitalized by a "rate of interest" charged on long term loans secured by a mortgage on farm or agricultural land plus a component for property taxes.