Cal. Pub. Util. Code § 27501

The board of any district which operates no transit facilities, or with exterior boundaries coincident with the boundaries of a single city, may call an election at any time for the purpose of submitting to the voters of the district the question of whether the district will be dissolved. Upon the filing with the secretary of such a district of a petition signed by voters within the district equal in number to at least 25 percent of the total vote cast, asking that the question of dissolution of the district be submitted to the voters of the district, the board shall call such an election.