For the purpose of providing funds for the maintenance of the city sanitary sewerage system and for other purposes, there are hereby fixed and established charges for the use of the sanitary sewer system to be imposed against each respective user thereof within the city in such amounts and according to such classifications of users as the city council, by resolution or motion, may determine. A copy of the current charges in effect shall be kept on file in the city clerk's office. (2016 Code)