Texas Constitution art. 11 §5

(a) Cities having more than five thousand (5000) inhabitants may, by a majority vote of the qualified voters of said city, at an election held for that purpose, adopt or amend their charters. If the number of inhabitants of cities that have adopted or amended their charters under this section is reduced to five thousand (5000) or fewer, the cities still may amend their charters by a majority vote of the qualified voters of said city at an election held for that purpose. The adoption or amendment of charters is subject to such limitations as may be prescribed by the Legislature, and no charter or any ordinance passed under said charter shall contain any provision inconsistent with the Constitution of the State, or of the general laws enacted by the Legislature of this State. Said cities may levy, assess and collect such taxes as may be authorized by law or by their charters; but no tax for any purpose shall ever be lawful for any one year, which shall exceed two and one-half per cent. of the taxable property of such city, and no debt shall ever be created by any city, unless at the same time provision be made to assess and collect annually a sufficient sum to pay the interest thereon and creating a sinking fund of at least two per cent. thereon, except as provided by Subsection (b). Furthermore, no city charter shall be altered, amended or repealed oftener than every two years. (b) To increase efficiency and effectiveness to the greatest extent possible, the legislature may by general law authorize cities to enter into interlocal contracts with other cities or counties without meeting the assessment and sinking fund requirements under Subsection (a). (Feb. 15, 1876. Amended Aug. 3, 1909, Nov. 5, 1912, Nov. 5, 1991, and Nov. 8, 2011.)