Tex. Const. art. VIII, § 21

(a) Subject to any exceptions prescribed by general law, the total amount of property taxes imposed by a political subdivision in any year may not exceed the total amount of property taxes imposed by that subdivision in the preceding year unless the governing body of the subdivision gives notice of its intent to consider an increase in taxes and holds a public hearing on the proposed increase before it increases those total taxes. The legislature shall prescribe by law the form, content, timing, and methods of giving the notice and the rules for the conduct of the hearing.

(b) In calculating the total amount of taxes imposed in the current year for the purposes of Subsection (a) of this section, the taxes on property in territory added to the political subdivision since the preceding year and on new improvements that were not taxable in the preceding year are excluded. In calculating the total amount of taxes imposed in the preceding year for the purposes of Subsection (a) of this section, the taxes imposed on real property that is not taxable by the subdivision in the current year are excluded.

(c) The legislature by general law shall require that, subject to reasonable exceptions, a property owner be given notice of a revaluation of his property and a reasonable estimate of the amount of taxes that would be imposed on his property if the total amount of property taxes for the subdivision were not increased according to any law enacted pursuant to Subsection (a) of this section. The notice must be given before the procedures required in Subsection (a) are instituted.