RCW 36.32.050: Election.

(1) Except as provided otherwise in subsection (2) of this section or this chapter, county commissioners shall be elected by the qualified voters of the county and the person receiving the highest number of votes for the office of commissioner for the district in which he or she resides shall be declared duly elected from that district.

(2) Beginning in 2022, in any noncharter county with a population of four hundred thousand or more, county commissioners must be nominated and elected by the qualified electors of the commissioner district in which he or she resides. The person receiving the highest number of votes at a general election for the office of commissioner for the district in which he or she resides must be declared duly elected from that district.