Cal. Elections Code § 15101

(a) An elections official may begin to process vote by mail ballot return envelopes and vote by mail ballots on the date on which the ballots are mailed, which shall not be later than 29 days before the election. (b) (1) Processing vote by mail ballot return envelopes may include verifying the voter’s signature on the vote by mail ballot return envelope pursuant to Section 3019 and updating voter history records. (2) Processing vote by mail ballots includes opening vote by mail ballot return envelopes, removing ballots, duplicating any damaged ballots, and preparing the ballots to be machine read, or machine reading them, including processing write-in votes so that they can be tallied by the machine, but under no circumstances may a vote count be accessed or released until 8 p.m. on the day of the election. (c) Results of any vote by mail ballot tabulation or count shall not be released before the close of the polls on the day of the election.