Section 15154 Of Article 1. General Provisions From California Elections Code >> Division 15. >> Chapter 3. >> Article 1.

. (a) Any ballot that is not marked as provided by law shall be rejected. The rejected ballots shall be placed in the package marked for voted ballots or in a separate container as directed by the elections official. All rejected ballots shall have written on the ballot the cause for rejection and be signed by a majority of processing board members who are assigned by the elections official to process ballots.
  (b) The following ballot conditions shall not render a ballot invalid:
  (1) Soiled or defaced.
  (2) Two or more impressions of the voting stamp or mark in one voting square.
  (3) Contains personal information, as defined in Section 14287.
  (c) If a voter indicates, either by a combination of both marking and writing in, a choice of more names than there are candidates to be elected or nominated for any office, or if for any reason the choice of the voter is impossible to determine, the vote for that office shall not be counted, but the remainder of the ballot, if properly marked, shall be counted.
  (d) This section applies to all ballots counted pursuant to this chapter and Chapter 4 (commencing with Section 15300).