California Code, Health and Safety Code - HSC § 40424

(a) Except as provided in subdivision (b), seven members of the south coast district board shall constitute a quorum, and no official action shall be taken by the south coast district board except in the presence of a quorum and upon the affirmative votes of a majority of the members of the south coast district board.

(b) Notwithstanding subdivision (a), whenever there are two or more vacancies on the south coast district board, six members shall constitute a quorum, and the two vacant positions shall not be counted toward the majority required for official action by the south coast district board. Thereafter, whenever at least one of those vacancies is filled, the quorum and voting requirements of subdivision (a) shall apply.