California Code, Public Utilities Code - PUC § 24862

Of the directors elected at the first election following the formation election, those three elected by wards and the one elected at large by the highest vote shall hold office for four years, and the other three for two years, and until their successors are elected and qualified. Thereafter, at each biennial general election, a number of directors corresponding to the number whose terms of office expire shall be elected for the term of four years.