Cal. Wat. Code § 35539.3
If, after the board adopts the resolution of intent to levy and before 30 days after the resolution pursuant to the hearing, the board receives a petition containing the signatures of persons holding title to 5 percent of the land area within the district, the board shall call an election of the qualified voters in the district and submit the resolution to levy the special assessment to the voters for their approval or rejection. When an election is required pursuant to this section, no levy of assessment pursuant to this article shall be made unless and until the election required by this section is held and the assessment is approved by a majority vote of the qualified voters of the district in such election. The election required in this section shall be called and noticed, held and conducted in the manner provided for bond elections of the district.
Ca. Water Code § 35539.3