Cal. Water Code § 41550

If a general election is not held as provided in this part, then upon the filing of a petition with the secretary, signed by the holders of title to more than 15 percent of the total assessed valuation of the land, or the holders of contracts to purchase such land executed by the holders of title thereto and qualified to vote in accordance with the provisions of Section 41006, requesting that a special election be called for the election of officers, the board shall thereupon call a special election for the election of officers. The election shall be held within not less than 15, nor more than 30, days after the filing of the petition.