Cal. Education Code § 44836

(a) (1) The governing board of a school district shall not employ or retain in employment persons in public school service who have been convicted, or who have been convicted following a plea of nolo contendere to charges, of any sex offense as defined in Section 44010. (2) If a person’s conviction of a sex offense as defined in Section 44010 is reversed and the person is acquitted of the offense in a new trial or the charges against him or her are dismissed, this section does not prohibit his or her employment thereafter. If the dismissal was pursuant to Section 1203.4 of the Penal Code and the victim of the sex offense was a minor, this section does prohibit the person’s employment. (b) (1) The governing board of a school district also shall not employ or retain in employment persons in public school service who have been convicted of any controlled substance offense as defined in Section 44011. (2) If a person’s conviction for a controlled substance offense as defined in Section 44011 is reversed and the person is acquitted of the offense in a new trial or the charges against him or her are dismissed, this section does not prohibit his or her employment thereafter. (c) Notwithstanding subdivision (b), the governing board of a school district may employ a person convicted of a controlled substance offense in a position requiring certification qualifications if that person holds an appropriate credential issued by the Commission on Teacher Credentialing.