Section 115. Sale of Water

Water  shall be sold in bulk to the several
  contracting municipalities. Rates shall be fixed in  such  amounts  that
  revenue  therefrom  shall  be  at  least sufficient to pay all estimated
  annual costs of operation  and  maintenance  and  debt  service  on  all
  obligations  issued  for the purposes of a common supply, whether or not
  such obligations are joint obligations. In the event that such  revenues
  in  any  year  are insufficient, the excess of cost over revenues may be
  apportioned to the participating municipalities and shall be assessed by
  each against the real property within its boundaries.