Section 1.  Notwithstanding any general or special law to the contrary, the following procedures shall apply in the Town of Barnstable to assessments pursuant to chapters 80 or 83 of the General Laws for making and repairing sewers within the Town of Barnstable.

(a) At any time before the completion by the assessors of the valuation list for the year in which assessments for making and repairing sewers will first appear on the annual tax bill, the board of assessors may, and at the request of the owner of the land assessed shall, apportion all such assessments or unpaid balances thereof into such number of equal portions, not exceeding thirty years or the useful life of the main drains and common sewers as approved by the department of environmental protection, whichever is less, as is determined by said board or as is requested by the owner of land, but no one of such portions shall be less than five dollars.

(b) Assessments made in accordance with subsection (a) may be determined by the board of assessors so that the principle and interest combined for each portion of all assessments and unpaid balances shall be as nearly equal as practicable.

(c) The annual portion adopted by the board of assessors pursuant to subsection (a) shall be billed and collected at the election of the town on quarterly, semi-annual or a single-tax bill or bills, as the board of assessors shall determine.

Section 2.  This act shall take effect upon its passage and apply to all betterments and assessments made after April 7, 2011.