Section 14. A person who enters his particular drain into a main drain or common sewer, or who by more remote means receives benefit thereby for draining his land or buildings, shall pay to the town a proportional part of the charge of making and repairing the same, and of the charge, not already assessed, of making and repairing other main drains and common sewers through which the same discharges, which shall be ascertained, assessed and certified by the aldermen, sewer commissioners, selectmen or road commissioners.