The monthly rates to be charged for sanitary sewer service and for making connections shall be determined by ordinance. Such monthly charges for sewer service shall be designed to assure that each recipient of waste treatment service will pay the recipient’s proportionate share of the cost of operation and maintenance of the treatment works, including replacement of such facilities during the life of the project, in accordance with the requirements of the U.S. Environmental Protection Agency or the Alaska Department of Environmental Conservation, as applicable.