The governing authorities of municipalities shall have the power to erect, purchase, maintain and operate waterworks, and to regulate the same, to prescribe the rates at which water shall be supplied to the inhabitants, and to acquire by purchase, donation or condemnation, in the name of the municipality, suitable grounds, within or without the corporate limits, upon which to erect waterworks, and also the right-of-way to and from such works and the right-of-way for laying water pipes within the corporate limits, and from such waterworks to the municipality, and to extend such right-of-way from time to time. The governing authorities shall have the power to contract with any person for the maintenance and operation of waterworks. Said authorities shall have the power to contract with any person for the erection and maintenance of waterworks for a term not exceeding twenty-five (25) years, fixing water rates in the contract subject to municipal regulations. A contract for the erection or purchase of waterworks shall not, however, be entered into until submitted to a vote of the qualified electors and approved by a majority of those voting. A contract for maintenance under which the person who will perform such maintenance is wholly or partially responsible for fixing water rates shall not be entered into until submitted to a vote of the qualified electors and approved by a majority of those voting. It shall be unlawful for any municipally owned waterworks to supply water free of charge, or in any amount less than the fixed charges, to any person, firm or corporation, except as is expressly authorized by law.