(a) Each municipality owning a sewer system shall have the power to establish and collect and from time to time alter charges for service furnished by or from said sewer system. All such charges shall be uniform for the same type, class, and amount of use of or service by or from the sewer system, and such charges may be measured or computed on the basis of any one or more or combination of the following:
(1) The quantity of water used upon the premises served by the sewer system;
(2) The number and kind of water outlets upon or in connection with such premises;
(3) The number and kind of plumbing facilities or sewer fixtures on or in connection with such premises;
(4) The number of persons residing or working in or otherwise connected with or using such premises;
(5) The type or character of such premises;
(6) The capacity of the improvements on or connected with such premises; and,
(7) Any other factors determining the type, class, and amount of the use of or service by or from the sewer system; provided, however, that if any such charge shall be measured by the quantity of water used, the municipality shall make appropriate provision for adjustment of charges on account of consumption of water which does not enter the sewer system.
(b) Any charges for sewer service, measured by quantity of water used, to users of the sewer system who obtain all or any part of their water supply from sources other than the water system of the municipality may be determined by gauging or metering or in any other manner approved by the municipality.
(c) In cases where the character of the sewage from any premises is such that it imposes an unreasonable burden upon the sewer system, the service rendered by the sewer to such premises may be given a special classification in the municipality's schedule of sewer service charges and an additional charge may be made for such special classification of service, or the municipality may require such sewage to be treated in such manner as shall be specified by the municipality before it is discharged into the sewer system.
(d) Any municipality may combine its sewer system and any water distribution system owned by it and may establish a single schedule of rates, fees, and charges for the water and services furnished by such combined system and may provide for reductions in such schedule in cases where water is furnished to premises that are not connected with the sewer system.