Tex. Educ. Code § 12.022

Voting early and often in Texas:

§ 12.022. Minimum Voter Turnout Required

(a) An election on the adoption of a proposed home-rule school district charter has no effect unless at least 25 percent of the registered voters of the district vote in the election in which the adoption of the charter is on the ballot.

(b) An election on the adoption of a proposed amendment to a home-rule school district charter has no effect unless at least 20 percent of the registered voters of the district vote in the election in which the adoption of the amendment is on the ballot.

(c) If the required number of voters prescribed by Subsection (a) or (b) do not vote in the election, the board of trustees shall order an election on the issue to be held on the first uniform election date:
(1) that occurs at least 45 days after the date the election is ordered; and
(2) on which one or more elections are to be held, the combination of which covers all of the territory of the school district.

(d) If the required number of voters prescribed by Subsection (a) or (b) do not vote at an election ordered as required by Subsection (c), the board of trustees may continue to order elections on the issue in accordance with Subsection (c) until the required minimum voter turnout is achieved.