In the resolution creating a district initiated in accordance with Section 19-5-153(3), the board of supervisors shall direct the existing board of directors of the rural water association to create within the district five (5) posts from which commissioners shall be elected. The board of supervisors shall designate the positions to be elected from each post as Post 1, Post 2, Post 3, Post 4 and Post 5. Post 5 shall be an at-large post composed of the entire district. Within sixty (60) days following creation of the district, the board of supervisors shall call an election. Such election shall be held and conducted by the election commissioners in accordance with the general laws governing elections. The election commissioners shall determine which of the qualified electors of the county reside within the district and only those electors shall be entitled to vote in the election. Notice of the election setting forth the time, place or places and the purpose of the election shall be published by the clerk of the board of supervisors in the manner provided in Section 19-5-155. The initial elected commissioners shall be elected to a term of office expiring on December 31 of the year in which the next succeeding general election for statewide officials is held. After the initial term of office, commissioners shall be elected to four-year terms. Vacancies shall be filled by the procedure set forth in Section 23-15-839.