As provided by Subchapter J, Chapter 49, Water Code, the board may add territory to the district, subject to § 54.016, Water Code, or remove territory from the district, except that:
(1) the addition or removal of the territory must be approved by three-fourths of all the members of the governing body of the city; and
(2) territory may not be removed from the district if bonds or other obligations of the district payable wholly or partly from assessments levied or assessed on the territory are outstanding.