Cal. Penal Code § 903.1

Pursuant to written rules or instructions adopted by a majority of the judges of the superior court of the county, the jury commissioner shall furnish the judges of the court annually a list of persons qualified to serve as grand jurors during the ensuing fiscal year of the county, or until a new list of jurors is required. From time to time, a majority of the judges of the superior court may adopt such rules or instructions as may be necessary for the guidance of the jury commissioner, who shall at all times be under the supervision and control of the judges of the court. Any list of jurors prepared pursuant to this article must, however, meet the requirements of Section 899.