Wash. Rev. Code § 84.34.370
Whenever a portion of a parcel of land which was classified as farm and agricultural or timberland pursuant to this chapter is withdrawn or removed from classification ((or there is a change in use)), and such land has been exempted from any benefit assessments pursuant to RCW 84.34.320, the previously exempt benefit assessments ((shall)) become due on only that portion of the land which is withdrawn or ((changed)) removed.
[ 2014 c 97 s 315; 1992 c 52 s 20; 1979 c 84 s 8.]