Whenever, on the first day of January of any year, two installments of any local improvement assessment are delinquent, or the final installment of any such assessment or the entire assessment where payable on the “immediate payment” plan has been delinquent for more than one year, the finance director shall, on or before the first day of July of such year, proceed with the foreclosure of such assessment, or installments thereof, in accordance with Chapter 35.50 RCW. (1957 code § 8.04.030.)