After the establishment of a system of sewerage in any city of the first class, the mayor and city council may, at the time of levying other taxes for city purposes, levy an annual tax of not more than three and five-tenths cents on each one hundred dollars upon the taxable value of all the taxable property in such city for the purpose of creating a fund to be used exclusively for the maintenance and repairing of any sewers in such city. In lieu of the levy of a tax, the mayor and city council may establish, by ordinance, such rates for such sewer service as may be deemed by them to be fair and reasonable, to be collected from either the owner or the person, firm, or corporation requesting the service at such times, either monthly, quarterly, or otherwise, as may be specified in the ordinance. All such sewer charges shall be a lien upon the premises or real estate for which the sewer service is used or supplied. Such lien shall be enforced in such manner as the city council provides by ordinance. The charges thus made, when collected, shall be placed in a separate fund and used exclusively for the purpose of maintenance and repairs of any sewers in such city.