When an agreement is made as to the amount that shall be paid by those outside the municipality, as provided in section 3403 of this title, the selectboard shall forthwith give notice to all real estate owners benefited by such sewer, drain, or outlet, when and where they will hear and determine the amount of expense to be borne by each party so benefited. Such notice may be delivered in writing to the party or served like a writ of summons.