RCW 35.49.050: Prepayment of installments subsequently due.

The owner of any lot, tract, or parcel of land or other property charged with a local improvement assessment may redeem it from all liability for the unpaid amount of the assessment at any time after the thirty day period allowed for payment of assessments without penalty or interest by paying the entire installments of the assessment remaining unpaid to the city or town treasurer with interest thereon to the date of maturity of the installment next falling due.