At the time bonds or other obligations payable wholly or partly from ad valorem taxes are issued,
the board shall provide for the annual imposition of a continuing direct annual ad valorem tax, without limit to the rate or amount of the tax while all or part of the bonds are outstanding as provided by Sections 54.601 and 54.602, Water Code.
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Tex. Spec. Dist. Loc. Laws § 8221.202