(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:
(1) pay the interest on the bonds; and
(2) create a sinking fund of at least two percent on the bonds.
(b) The rate of the tax may not exceed 50 cents on the $100 valuation of property taxable by the municipality.