At the time of confirmation of such assessments, it shall be competent for the court to order the assessments for cost of construction, to be paid in not more than fifteen installments of such amounts and at such times as will be convenient for the accomplishment of the proposed work, or for the payment of the principal and interest of such notes or bonds of said district as the court shall grant authority to issue, for the cost of construction. The court may also, by such order, fix a date on which the first installment of the assessments for cost of construction shall become due, not more than five years after the date of the order, and each of said installments shall draw interest at the rate of not to exceed eight percent per annum from the date of said order.