Tex. Water Code § 54.603
In the event the board fails or refuses to levy a sufficient tax in each year which, together with other revenues or receipts which may be legally used for these purposes, will be sufficient to pay the required principal of or interest or redemption price on the bonds, notes, or other contractual obligations when due, or to pay the district's other contractual obligations payable from taxes in addition to all other remedies which may be available, the owner of the district's bonds, notes, or other contractual obligations shall be entitled to a writ of mandamus issued by a court of competent jurisdiction to compel the board to levy a sufficient tax to meet the district's obligations to the owners of its bonds, notes, or other contractual obligations.
Tex. Water Code § 54.603