Bills for the rates and charges herein established shall be made and sent out monthly. The bills shall be due and payable on the fifteenth day following the date of rendition. All bills shall be payable at the office of the city collector. If any charges for the service of the system shall not be paid by the fifteenth day following the date of rendition of the bill, a delayed payment charge of ten percent (10%) of the amount of the bill shall be added thereto and collected therewith. (Ord. 516, 4-15-1991)