Tex. Water Code § 49.23602

(a) In this section:

(1) "Developed district" means a district that has financed, completed, and issued bonds to pay for all land, works, improvements, facilities, plants, equipment, and appliances necessary to serve at least 95 percent of the projected build-out of the district in accordance with the purposes for its creation or the purposes authorized by the constitution, this code, or any other law.

(2) "Mandatory tax election rate" means the rate equal to the sum of the following tax rates for the district:

(A) the rate that would impose 1.035 times the amount of tax imposed by the district in the preceding year on a residence homestead appraised at the average appraised value of a residence homestead in the district in that year, disregarding any homestead exemption available only to disabled persons or persons 65 years of age or older; and

(B) the unused increment rate.

(3) "Unused increment rate" has the meaning assigned by Section 26.013, Tax Code.

(4) "Voter-approval tax rate" means the rate equal to the sum of the following tax rates for the district:

(A) the current year's debt service tax rate;

(B) the current year's contract tax rate;

(C) the operation and maintenance tax rate that would impose 1.035 times the amount of the operation and maintenance tax imposed by the district in the preceding year on a residence homestead appraised at the average appraised value of a residence homestead in the district in that year, disregarding any homestead exemption available only to disabled persons or persons 65 years of age or older; and

(D) the unused increment rate.

(b) This section applies only to a developed district that is not a district described by Section 49.23601.

(c) If the board of a district adopts a combined debt service, contract, and operation and maintenance tax rate that exceeds the district's mandatory tax election rate, an election must be held in accordance with the procedures provided by Sections 26.07(c)-(g), Tax Code, to determine whether to approve the adopted tax rate. If the adopted tax rate is not approved at the election, the district's tax rate is the voter-approval tax rate. An election is not required if the adopted tax rate is less than or equal to the voter-approval tax rate.

(d) Notwithstanding any other provision of this section, the board of a district may give notice under Section 49.236(a)(3)(A), determine whether an election is required to approve the adopted tax rate of the district in the manner provided for a district under Section 49.23601(c), and calculate the voter-approval tax rate of the district in the manner provided for a district under Section 49.23601(a) if any part of the district is located in an area declared a disaster area during the current tax year by the governor or by the president of the United States. The board may continue doing so until the earlier of:

(1) the second tax year in which the total taxable value of property taxable by the district as shown on the appraisal roll for the district submitted by the assessor for the district to the board exceeds the total taxable value of property taxable by the district on January 1 of the tax year in which the disaster occurred; or

(2) the third tax year after the tax year in which the disaster occurred.