California Code, Elections Code - ELEC § 8026

(a) Notwithstanding any other provision of law, except for an election for a judicial office, an election shall not be conducted and no votes cast for the office shall be counted, and if counted the votes shall be null and void, if an incumbent is a candidate for a nonpartisan statewide, countywide, or citywide office, or for a nonpartisan office that is elected by division, area, or district, which he or she currently holds at an election at which only one other candidate, excluding any write-in candidates, has qualified to have his or her name placed on the ballot for that office, and either the challenger or the incumbent dies after the hour of 12:01 a.m. of the 68th day before the election.

(b) A special election shall be called and held when the death of the challenger or the incumbent occurs within the period set in subdivision (a).  The special election shall be called by the appropriate governing body within 14 days after the death of the incumbent or challenger.  The special election shall be held no later than 88 days after the proclamation or resolution calling for the election.  Candidates at the special election shall be nominated in accordance with this part, except that forms for securing signatures in lieu of a filing fee need not be made available until 15 days before the first day for circulating nomination papers, in-lieu-filing-fee petitions shall be filed at least seven days prior to the closing of the nomination period, nomination papers shall be delivered for filing to the elections official not less than 68 days and not more than 87 days before the special election, any candidate's statement shall be filed with the clerk no later than the 68th day before the special election, and the Secretary of State shall conduct the randomized alphabet drawing under procedures similar to Sections 13112 and 13113 on the 67th day before the special election.  Any candidate who paid a filing fee in connection with the previously scheduled election shall not be required to pay any additional filing fee, but shall be required to file new nomination papers.

(c) The Secretary of State or elections official shall take appropriate action to ensure that voters do not erroneously vote in a canceled election.

(d) This section applies to a primary election.  If a candidate in a runoff election dies under the circumstances prescribed in subdivision (a), Section 15402 applies to govern the results of that election.