The board of commissioners may designate, define and create one or more water districts within the township, and the board of commissioners shall determine the proportion of the cost of the water system which shall be equitably charged on each district and declare and establish the apportionment by resolution. No district shall be charged with more than its due proportion of the cost of the main pipe lines, pumping stations or other parts of the water system used jointly by more than one district.
53 P.S. § 57706