Cal. Elections Code § 17304

(a) The following provisions apply to all state or local elections not provided for in subdivision (a) of Section 17303. An election is not deemed a state or local election if votes for candidates for federal office may be cast on the same ballot as votes for candidates for state or local office. (b) The elections official shall preserve the package or packages containing the following items for a period of six months: (1) Two tally sheets. (2) The copy of the roster used as the voting record. If an electronic poll book is used, a copy of the electronic data file may be preserved in lieu of creating a paper copy. (3) The challenge lists. (4) The assisted voters’ list. (c) All voters may inspect the contents of the package or packages at all times following commencement of the official canvass of the votes, except that items that contain signatures of voters may not be copied or distributed. (d) If a contest is not commenced within the six-month period, or if a criminal prosecution involving fraudulent use, marking or falsification of ballots, or forgery of vote by mail voters’ signatures is not commenced within the six-month period, either of which may involve the vote of the precinct from which voted ballots were received, the elections official may have the packages destroyed or recycled.