Section 21503 Of Chapter 6. Supervisorial Districts From California Elections Code >> Division 21. >> Chapter 6.

. At any time between the decennial adjustments of district boundaries, the board may cause a census of the county to be taken as provided in Section 26203 of the Government Code, and may adjust the boundaries of the supervisorial districts on the basis of that census, or on the basis of population estimates prepared by the State Department of Finance or the county planning department or planning commission, pursuant to Section 21500.