California Code, Water Code - WAT § 30516

(a) If the Orange County local agency formation commission orders the reorganization of the Capistrano Beach County Water District and the Capistrano Beach Sanitary District into a single district, the board of directors of the reorganized district shall, notwithstanding Section 30500 or any other provision of law, initially consist of 10 members, who shall be the combined boards of directors of the two districts as of the effective date of the reorganization.

(b) Upon the expiration of the terms of the members of the board of directors of the reorganized district whose terms first expire following the effective date of the reorganization, the total number of members on the board of directors shall be reduced to seven members. Upon the expiration of the succeeding terms of the members of the board of directors of the reorganized district, the total number of members of the board of directors shall be reduced to five members.

(c) In addition to the powers granted under Section 1780 of the Government Code, in the event of a vacancy on the board of directors of the reorganized district at which time the total number of directors is greater than five, the board of directors may, by majority vote of the remaining members of the board, choose not to fill the vacancy. In that event the total membership of the board of directors shall be reduced by one board member. Upon making the determination not to fill a vacancy, the board of directors shall notify the board of supervisors of its decision.