Wash. Rev. Code § 87.68.020
In the event of the adoption and entering of such resolution by the board of directors, a person paying all or one-half of the current district assessment against any tract of land on or before December 31st of the year in which said assessment is levied shall be entitled to a discount of ten percent of said assessment if paid in full and ten percent of one-half of said assessment if one-half only is paid. In the event one-half of said assessment is paid on or before December 31st as aforesaid, the payer of the second half of said assessment shall be entitled to a discount of ten percent of the amount of said second half of said assessment if the same is paid on or before May 31st, next following the December payment. No discount shall be made for payment of district assessments except as herein specifically provided.
RCW 87.68.020
Severability-Construction-1941 c 141: See notes following RCW 87.68.010.