GOV §31557: All officers and employees of any district become members of the association on the first day of the calendar month after: (a) In the case of districts for which the board of supervisors is the govern

All officers and employees of any district become members of the association on the first day of the calendar month after: (a) In the case of districts for which the board of supervisors is the governing body, such body adopts by four-fifths vote a resolution providing for the inclusion of the district in the retirement association. (b) In the case of districts for which the board of supervisors is not the governing body, the governing body adopts by a two-thirds vote, a resolution providing for the inclusion of the district in the retirement association and the board, by majority vote, consents thereto. Thereafter, each person entering such employment becomes a member on the first day of the calendar month following his entrance into the service. However, if prior to January 1, 1976, the governing body and the board of retirement have executed an agreement providing for the purchase of prior service, the agreement may be amended to provide that the date of membership in the retirement association for any officer or employee shall be the first day of the calendar month following the officer’s or employee’s entrance into district service. Members may be withdrawn from the association in the manner provided in Section 31564.