Wash. Rev. Code § 91.08.390
The owner of any land charged with an assessment under this chapter, may discharge the same from all liability for the cost of such condemnation and improvement by paying the entire assessment charged against his or her land, without interest, within the time fixed by the notice of the county treasurer for the payment thereof; or within said time he or she may pay a part of such assessment and allow the remainder to continue as an assessment upon his or her land to be collected and paid as hereinafter provided; or within said time he or she may pay the entire assessment per square foot upon any part of his or her land, providing that he or she shall when paying such partial assessment give to the treasurer a description of the tract paid for.
RCW 91.08.390
Payment of assessments by satisfying judgment: RCW 91.08.590.