Section 120. Contracts for purification of water and sewerage

The local
  authorities of the several counties, cities, towns and villages  of  the
  state  having  charge of the supply of water and the care of sewerage in
  their respective localities, are hereby authorized, on behalf  of  their
  counties,  cities,  towns  and  villages,  respectively,  to  enter into
  contracts  with  the  owners  of  any  process  or  apparatus  for   the
  purification  of water and sewerage whether protected by patents or not,
  and either contract for the use of apparatus and process for a  term  of
  years  or for the purchase of the same, as to them shall seem advisable.
  It shall be lawful for any two or more of such  municipalities  in  this
  state,  without  regard  to  the  form of their incorporation, including
  towns or sewer  districts  of  towns,  to  jointly  construct,  provide,
  maintain  and operate a comprehensive system of sewerage including trunk
  lines and laterals, or a system of conveying or conducting sewerage from
  said municipalities from a point or points to be agreed upon to a common
  destination or disposal plant or plants, and to construct, maintain  and
  operate  within or without the said municipalities or any of them one or
  more  outlet  or  trunk  sewers,  plants,  works  or  stations  for  the
  treatment,  disposal, or rendering of sewerage, or any such municipality
  or any such municipalities may jointly or  severally  contract  for  the
  construction  for  it  or  them  of  any  such system, extension or part
  thereof, including any such sewers, plants, works or stations, and agree
  to pay annually, semi-annually or quarterly for the  use  or  possession
  thereof,  by  way  of permanent rental reserved therefor; or such lawful
  authorities of the respective municipalities may  jointly  or  severally
  contract   with  any  person,  persons  or  corporation  or  with  other
  municipalities or sewage districts for the removal of sewage within  the
  boundaries  of such local government, upon such reasonable terms as they
  may agree upon. And to that end the governing bodies or  boards  of  any
  two  or  more  municipalities,  including  sewer  districts  of  a town,
  authorized by law to have charge of sewer systems established or  to  be
  established  in  said  municipalities,  or  sewer  districts  of a town,
  respectively, may unite and jointly cause to  be  made  at  their  joint
  expense  (each  district  bearing a part of the expense in proportion to
  the assessed valuation of real estate in such district, or on such other
  basis or division as may be jointly agreed upon) by competent engineers,
  mechanics and others, surveys, maps, plans,  reports  and  estimates  of
  proposed  works  and  improvements  relating to such contemplated public
  improvement or works authorized by this act, which  such  municipalities
  may  desire  to  jointly  provide,  maintain, operate or lease under the
  authority conferred by this act, and for such purpose they may determine
  upon the final route and plan for the building or construction  of  such
  sewerage system and for the making of such surveys, maps, plans, reports
  and  estimates  as  provided in this section. It shall be lawful for the
  officers and agents of such municipalities to enter at  all  times  upon
  any  lands or waters for the purpose of exploring, surveying, and laying
  out the route of such sewerage system.