Health and Safety Code § 9022

(a) Each person appointed by a board of supervisors to be a member of a board of trustees shall be a voter in the district.

(b) All trustees shall exercise their independent judgment on behalf of the interests of the residents, property owners, and the public as a whole in furthering the purposes and intent of this part. The trustees shall represent the interests of the public as a whole and not solely the interests of the board of supervisors that appointed them.