Section 21501 Of Chapter 6. Supervisorial Districts From California Elections Code >> Division 21. >> Chapter 6.

. The boundaries of the supervisorial districts shall be adjusted by the board before the first day of November of the year following the year in which each decennial federal census is taken. If the board fails to adjust the boundaries before the first day of November following the year in which the federal census is taken, a supervisorial redistricting commission shall do so before the 31st day of December of the same year. The adjustment of the district boundaries shall be immediately effective the same as if the act of the supervisorial redistricting commission were an ordinance of the board, subject, however, to the same provisions of referendum as apply to ordinances of the board.