7-13-101. Authorization to create metropolitan sanitary and/or storm sewer districts. Whenever the public convenience and necessity may require, in order to construct sanitary and/or storm sewer systems within any county, which sanitary and/or storm sewer systems would serve the inhabitants of any county as well as the inhabitants of any city or town within said county, the board of county commissioners, with the approval of the city or town council, may create metropolitan sanitary and/or storm sewer districts.