(A) In order that the rates and charges for sewage services may remain fair and equitable and be in proportion to the cost of providing services to the various users or classes, the city shall cause a study to be made within a reasonable period of time following the first two years of operation, following the date on which this chapter goes into effect. The study shall include, but not be limited to, an analysis of the costs associated with the treatment of excessive strength effluents from industrial users, volume and delivery flow rate characteristics attributed to the various users or user classes, the financial position of the sewage works and the adequacy of its revenue to provide reasonable funds for the operation and maintenance, replacements, debt service requirements and capital improvements to the waste treatment systems. In addition, any excess revenue collected from a class of users shall be applied to the next year’s cost attributed to that class and the rates shall be adjusted accordingly.
(B) Thereafter, on a biennial basis within a reasonable period of time following the normal accounting period, the city shall cause a similar study to be made for the purpose of reviewing the fairness and equity of the rates and charges for sewage services on a continuing basis. The studies shall be conducted by officers or employees of the city, by a firm of certified public accountants, a firm of consulting engineers, which firms shall have experience in these type of studies, or by a combination of officers, employees, certified public accountants or engineers as the city shall determine to be best under the circumstances.
(‘89 Code, § 103.07)