When the city has effected the removal, the actual cost thereof, and 15 percent plus accrued interest at the rate of six percent per year from the date of the completion of the work, if not paid by such owner prior thereto or the person responsible, shall be charged to such notified person and the charge shall be due and payable by the person at the time of receipt of such bill. (Ord. 4276 § 5, 1988; 1957 code § 7.12.210(C).)