Cal. Elections Code § 8605

No person whose name has been written in upon a ballot for an office at the direct primary may have his or her name placed upon the ballot as a candidate for that office for the ensuing general election unless one of the following is applicable: (a) At that direct primary he or she received for a partisan office votes equal in number to 1 percent of all votes cast for the office at the last preceding general election at which the office was filled. In the case of an office that has not appeared on the ballot since its creation, the requisite number of votes shall equal 1 percent of the number of all votes cast for the office that had the least number of votes in the most recent general election in the jurisdiction in which the write-in candidate is seeking office. (b) He or she is an independent nominee for a partisan office pursuant to Part 2 (commencing with Section 8300). (c) At that direct primary he or she received for a voter-nominated office the highest number of votes cast for that office or the second highest number of votes cast for that office, except as provided by subdivision (b) of Section 8142 or Section 8807.