RCW 84.60.070: Acquisition by governmental unit of property subject to tax lien or placement under agreement or order of immediate possession or use—Segregation of taxes if only part of parcel required.

When only part of a parcel of real property is required by a public body either of the parties may require the assessor to segregate the taxes and the assessed valuation as between the portion of property so required and the remainder thereof. If the assessed valuation of the portion of the property not required exceeds the amount of all delinquent taxes and taxes payable on the entire parcel, and if the owner so elects the lien for the taxes owing and payable on all the property shall be set over to the property retained by the owner. All county assessors are hereby authorized and required to segregate taxes as provided above.