(1) To defray the cost of such public sewers, the city or town council may appropriate moneys therefor from the general or sewer fund or by availing itself of money derived from a bond issue authorized by the constitution and laws of the state.
(2) It is further provided that when a public or main sewer also serves as a district sewer, the city council may assess the property bordering or abutting upon such public sewer, either at the time of its construction or at any future time, for an amount equal to the estimated cost of such district sewer capable of accommodating such property.