Tex. Spec. Dist. Code § 1035.158
(a) The district boundaries may be expanded or territory may be annexed to the district under this subchapter only if the expansion or annexation, the assumption of debt, and the imposition of taxes are approved by a majority of the voters voting at:
Added by Acts 2009, 81st Leg., R.S., Ch. 1139 (H.B. 2619), Sec. 1.01, eff. April 1, 2011.