Cal. Harb. & Nav. Code § 7040

Each district shall have a board of five directors all of whom shall be registered electors residing within the boundaries of the district and all of whom shall be elected at large. The directors first elected upon the formation of the district shall classify themselves by lot so that two of them shall hold office until the election and qualification of their successors at the first succeeding general district election, and three of them shall hold office until the election and qualification of their successors in the second general district election.