The Board of Supervisors may authorize the inclusion of additional member municipalities in the District upon such terms and conditions as it in its sole discretion shall deem to be fair, reasonable, and in the best interests of the District. The legislative branch of any nonmember municipality which desires to be admitted to the District shall make application for admission to the Board of Supervisors of the District. The Board shall determine the effects and impacts which are likely to occur if such municipality is admitted and shall thereafter either grant or deny authority for admission of the petitioning municipality. If the Board grants such authority, it shall also specify any terms and conditions, including financial obligations, upon which such admission is predicated. The petitioning municipality shall thereafter comply with the approval procedures specified in 24 V.S.A. chapter 121. If a majority of the voters of the petitioning municipality present and voting at a meeting of such municipality duly warned for such purpose shall vote to approve this chapter and the terms and conditions for admission, the vote shall be certified by the Clerk of that municipality to the Board of Supervisors. Thereafter, upon satisfactory performance of the terms and conditions of admission, the municipality shall by resolution of the Board of Supervisors become and thereafter be a member municipality of the District.