Section 42. Duty to supply water; contracts with municipalities

Such
  corporation shall supply each city, town or village  through  which  the
  conduits  or  mains  of  such  corporation  may  pass,  or  wherein such
  corporation may have organized, and the inhabitants thereof,  with  pure
  and  wholesome  water, at reasonable rates. The board of trustees of any
  incorporated village and the  water  commissioners  or  other  board  or
  officials performing the duties of water commissioners and having charge
  of the water supply of any city, shall have the power to contract in the
  name and behalf of the municipal corporation for the term of one year or
  more  for  the  delivery  by  such corporation to the village or city of
  water, through hydrants or otherwise, for the  extinguishment  of  fires
  and for sanitary and other public purposes. The amount agreed to be paid
  shall  be  annually  raised as a part of the expenses of such village or
  city, and shall be assessed, levied and collected in the same manner  as
  other expenses, and when collected shall be kept as a separate fund, and
  paid  according  to  the  terms and conditions of such contract. No such
  contract shall be made for a longer period than ten  years  nor  for  an
  annual  amount  exceeding  in  the  aggregate two and one-half mills for
  every dollar of the taxable property of such village or city, except (a)
  upon the petition of a majority of the taxable inhabitants of  any  such
  village or city, or of the portion thereof to be supplied, or (b) upon a
  proposition to authorize the same submitted to a vote of the electors of
  the  village  or city, in the manner provided by the village law or city
  charter, and approved by a majority of the voters entitled to  vote  and
  voting  thereon at an annual election or a special election duly called.
  Such contract shall be for a term not exceeding twenty years.