Cal. PEN § 1203.10

(a) At the time of the plea or verdict of guilty of any person over 18 years of age, a probation officer of the county of the jurisdiction of the criminal shall, when so directed by the court, inquire into the antecedents, character, history, family environment, and offense of such person, and must report the same to the court and file his or her report in writing in the records of such court. When directed, his or her report shall contain a recommendation for or against the release for the person on probation. If any such person shall be released on probation and committed to the supervision of a probation officer, such officer shall keep a complete and accurate record in suitable books of the history of the case and supervision, including the names of probation officers assigned to the case, and their actions in connection with the case; also the age, sex, nativity, residence, education, habit of temperance, whether married or single, and the conduct, employment and occupation, and parents’ occupation, if relevant, and condition of such person during the term of the probation and the result of the probation. The record of the probation officer is a part of the records of the court, and shall at all times be open to the inspection of the court or of any person appointed by, or allowed access by order of, the court for that purpose, as well as of all magistrates, and the chief of police, or other heads of the police, and other probation agencies, unless otherwise ordered by the court.

(b) Five years after termination of probation in any case subject to this section, the probation officer may destroy any records and papers in his or her possession relating to such case.