Cal. Gov. Code § 23330.5

No person shall file a petition pursuant to this article within five years of the date of certification, pursuant to Section 23328, of a prior petition which included in its description of boundaries for the proposed county any territory which is the subject of the new petition. The provisions of this section shall not apply to any new petition where the population of any affected county exceeds 5,000,000; however, the provisions of Section 23373 shall be applicable to such a new petition.