Immediately upon the close of polls on election day, the county elections officials and the Secretary of State begin what is called the "semifinal official canvass of the vote" - the tallying of early-returned vote-by-mail ballots and the ballots cast in each of the state's 24,000+ voting precincts. The semifinal official canvass begins at 8:00 p.m. on election night and continues uninterrupted until the last precinct is counted and reported to the Secretary of State.

The vote tallying process actually begins before election night, with the vote-by-mail ballots. Counties may begin processing vote-by-mail seven (7) business days before the election. Having verified the signatures on the return envelopes, elections officials remove the voted ballots and process them through their vote tallying system. Under no circumstances may they tabulate the results until after the close of polls on election day. Most counties continue this processing until they begin their election-day preparations for counting the precinct votes. Mail ballots not counted by that time and all those received on election day, either through the mail or at the precincts, are tabulated during the official canvass of the vote.

The California Elections Code requires that the official canvass begin no later than the Thursday following the election, that it be open to the public, and that it continue daily (Saturdays, Sundays, and holidays excepted) for not less than six hours each day until completed. The county elections officials must complete the official canvass no later than the 30th day after the election and submit a certified statement of the results of the election to the Secretary of State by the 31st day.

By law, the activities undertaken during the official canvass include:

  1. Processing and counting any valid vote-by-mail and provisional ballots not included in the semifinal official canvass. Provisional ballots are cast by voters whose names do not appear on the precinct roster. The voter uses a regular precinct ballot which is then placed in a special envelope that the voter must sign, much like a vote-by-mail envelope. During the official canvass, the elections official checks the voter registration file to verify the voter's eligibility to cast the ballot. Once verified, the ballot is added to the official count. These ballots added to the vote-by-mail ballots not processed on election night can number 500,000 to over 1,000,000.
  2. An inspection of all materials and supplies returned by poll workers.
  3. A reconciliation of the number of signatures on the roster with the number of ballots recorded on the ballot statement.
  4. A reconciliation of the number of ballots counted, spoiled, canceled, or invalidated due to identifying marks or overvotes with the number of votes counted, including vote-by-mail and provisional ballots.
  5. Counting any valid write-in votes.
  6. Reproducing any damaged ballots, if necessary.
  7. Conducting a hand count of the ballots cast in one (1) percent of the precincts, chosen at random by the elections official.
  8. Reporting final results to the Secretary of State, as required.

No later than the 38th day after the election, the Secretary of State must determine the votes cast for candidates for state and federal office and for the statewide ballot measures, certify those results, and issue certificates of nomination/election to those candidates who were nominated/elected.