Cal. Gov. Code § 50115

Unless another provision of law requires a longer retention period, the clerk of the legislative body may destroy or otherwise dispose of any paper or document filed with or submitted to the legislative body more than one year previously, unless the legislative body determines that there is a need for its retention. In determining whether there is a need for retaining a paper or document, consideration shall be given to such factors as future public need, the effect of statutes of limitation, and historical significance.