Cal. Code Regs. tit. 5, § 437 – Retention and Destruction of Pupil Records.

(a) No additions except routine updating shall be made to the record after high school graduation or permanent departure without the prior consent of the parent or adult pupil.
(b) Mandatory permanent pupil records shall be preserved in perpetuity by all California schools according to Chapter 2, Division 16, Part I, of this title.
(c) Unless forwarded to another district, mandatory interim pupil records may be adjudged to be disposable when the student leaves the district or when their usefulness ceases. Destruction shall be in accordance with Section 16027 of this title during the third school year following such classification.
(d) Permitted pupil records may be destroyed when their usefulness ceases. They may be destroyed after six months following the pupil's completion of or withdrawal from the educational program.
The method of destruction shall assure that records are not available to possible public inspection in the process of destruction.