(a) Any city of the first class or city of the second class may enact an ordinance by a majority vote of the elected and qualified members of its city council creating a waterworks commission to be composed of no less than three (3) nor more than seven (7) citizens who are qualified electors of the municipality or who are qualified electors of the area served by the municipality.
(b) Any waterworks commission of a city of the first class or city of the second class having less than seven (7) members may have its membership increased at any time to no more than seven (7) members by ordinance of the city council passed by the majority vote of the elected and qualified members of the city council.