Cal. Public Utilities Code § 90073

At any time within 30 days following the receipt by the board of supervisors of petitions or resolutions, or both, requiring the calling of an election pursuant to Section 90070, the board of supervisors may adopt a resolution of intention to include within the proposed San Diego County Transit District any unincorporated territory eligible for inclusion in the district as provided in Section 90050, and shall adopt such resolution of intention as to any such unincorporated territory upon receipt within such 30-day period of a petition signed by a number of signers equal to at least 5 percent of the voters registered for the last general election within any such territory requesting its inclusion in the proposed district and describing its boundaries. The board of supervisors by its resolution and registered voters by their petitions may propose the inclusion of such unincorporated territory in separate areas which are not themselves contiguous to each other. The board of supervisors shall, upon its adoption, refer such resolution of intention to the San Diego County Local Agency Formation Commission, which shall report to the board of supervisors within 30 days following receipt of the referral.