California Code, Public Utilities Code - PUC § 98100

The district shall be governed by a board of directors of seven members, which may be increased to 9 or 11 members if the board finds that an increase in the membership of the board is necessary to insure adequate representation to all of the areas in the County of Santa Cruz served by the district.  The membership shall be composed of one member appointed by the City Council of Santa Cruz, one member appointed by the City Council of Capitola, one member appointed by the City Council of Scotts Valley, one member appointed by the City Council of Watsonville, one member appointed by the governing bodies of any other incorporated areas in the county within the district to represent those incorporated areas, one member appointed by the Board of Supervisors of the County of Santa Cruz, and other members to be appointed by the above entities in accordance with their proportionate population within the district.  However, the membership of the board shall not exceed the number determined by the board.

The apportionment shall be based upon the population distribution within the district, and the board shall reapportion its membership whenever any part of the district is excluded or new territory is added or unincorporated territory within the district incorporates, and, as a result of the exclusion, annexation, or incorporation, representation on the board no longer reflects the population distribution within the district.  The board shall also reapportion whenever the county elections official advises the board that the latest official census indicates a need for reapportionment.