(a) At the time the district issues bonds payable wholly or partly from ad valorem taxes, the board shall provide for the annual imposition of an ad valorem tax, without limit as to rate or amount, as required by Section 54.601, Water Code.
(b) The board shall annually impose the tax while all or part of the bonds are outstanding. Sections 54.601 and 54.602, Water Code, govern the amount and rate of the tax.