Cal. Elec. Code § 8001

(a) No declaration of candidacy for a partisan office or for membership on a county central committee shall be filed by a candidate unless (1) at the time of presentation of the declaration and continuously for not less than three months immediately prior to that time, or for as long as he or she has been eligible to register to vote in the state, the candidate is shown by his or her affidavit of registration to be affiliated with the political party the nomination of which he or she seeks, and (2) the candidate has not been registered as affiliated with a qualified political party other than that political party the nomination of which he or she seeks within 12 months, or, in the case of an election governed by Chapter 1 (commencing with Section 10700) of Part 6 of Division 10, within three months immediately prior to the filing of the declaration.

(b) The elections official shall attach a certificate to the declaration of candidacy showing the date on which the candidate registered as intending to affiliate with the political party the nomination of which he or she seeks, and indicating that the candidate has not been affiliated with any other qualified political party for the period specified in subdivision (a) immediately preceding the filing of the declaration. This section does not apply to a declaration of candidacy filed by a candidate of a political party participating in its first direct primary election subsequent to its qualification as a political party pursuant to Section 5100 or by a candidate of a political party participating in its first presidential general election subsequent to its qualification as a political party pursuant to Section 5151.

(c) Notwithstanding subdivision (a), a county central committee, subject to the bylaws of the state central committee, may establish the length of time that a candidate for membership on that committee must be shown by his or her affidavit of registration to be affiliated with the political party of that committee, and may establish the length of time that a candidate for membership on that committee must not have been registered as affiliated with a qualified political party other than the political party of that committee.