53 Pa. Stat. § 2874
All assessments of benefits shall become due and payable to the municipality when the works and improvements have been completed, which date shall be fixed by the official order of the corporate authorities of the municipality, notice of which order shall be published by the board in the newspapers in which notice of the hearing before the viewers was published, by one insertion.
Any person may pay any part or all of the benefits assessed against him to the municipality before the due date thereof. If such payment is made within one month after the amount of the benefits have been finally ascertained, a discount of ten per centum of the amount thereof paid shall be allowed. All benefits, or any part thereof, paid after such one-month period and before the date of the completion of the works and improvements, shall be subject to a discount of five per centum of the amount paid. All assessments of benefits, or parts thereof, remaining unpaid when the improvements are completed, shall bear interest at the rate of six per centum per annum from the date of the completion of the works or improvements until paid.
The municipality shall send by registered mail addressed to the last known post office address, a statement of the amount due by each person after the same has been finally ascertained, together with a notice of the discounts allowed by this act for prompt payment, and when or approximately when interest will be added to the amount due.
53 P.S. § 2874