Cal. Penal Code § 916

Each grand jury shall choose its officers, except the foreman, and shall determine its rules of proceeding. Adoption of its rules of procedure and all public actions of the grand jury, whether concerning criminal or civil matters unless otherwise prescribed in law, including adoption of final reports, shall be only with the concurrence of that number of grand jurors necessary to find an indictment pursuant to Section 940. Rules of procedure shall include guidelines for that grand jury to ensure that all findings included in its final reports are supported by documented evidence, including reports of contract auditors or consultants, official records, or interviews attended by no fewer than two grand jurors and that all problems identified in a final report are accompanied by suggested means for their resolution, including financial, when applicable.