Tex. Gov't Code § 1506.057
(a) A municipality may not issue bonds under this subchapter creating a debt against the municipality or an improvement district unless the municipality provides for the imposition of an annual ad valorem tax on property in the improvement district at a rate sufficient to:
Added by Acts 1999, 76th Leg., ch. 227, Sec. 1, eff. Sept. 1, 1999.