(a) On or after the date the results are declared of an election held under § 3800.0602 at which the voters approved imposition of the tax authorized by this subchapter, the board shall determine and adopt by resolution or order the initial rate of the tax, which must be in one or more increments of one-eighth of one percent.
(b) After the authorization of a tax under § 3800.0602, the board may increase or decrease the rate of the tax by one or more increments of one-eighth of one percent.

(c) The board may not decrease the rate of the tax if the decrease would impair the repayment of any outstanding debt or obligation payable from the tax.
(d) The initial rate of the tax or any rate resulting from subsequent increases or decreases may not exceed the lesser of:
(1) the maximum rate authorized by the district voters at the election held under § 3800.0602; or
(2) a rate that, when added to the rates of all sales and use taxes imposed by other political subdivisions with territory in the district, would result in the maximum combined rate prescribed by § 321.101(f), Tax Code, at any location in the district.
(e) In determining whether the combined sales and use tax rate under Subsection (d)(2) would exceed the maximum combined rate prescribed by § 321.101(f), Tax Code, at any location in the district, the board shall include:
(1) any sales and use tax imposed by a political subdivision whose territory overlaps all or part of the district;
(2) any sales and use tax to be imposed by the county or a municipality in which the district is located as a result of an election held on the same date as the election held under § 3800.0602; and
(3) any increase to an existing sales and use tax imposed by the county or a municipality in which the district is located as a result of an election held on the same date as the election held under § 3800.0602.
(f) If the district adopts a sales and use tax authorized at an election under § 3800.0602 and subsequently includes new territory in the district, the district:
(1) is not required to hold another election to approve the imposition of the sales and use tax in the included territory; and
(2) shall impose the sales and use tax in the included territory as provided by Chapter 321, Tax Code.
(g) If the district adopts a sales and use tax authorized at an election under § 3800.0602 and subsequently excludes territory in the district, the sales and use tax is inapplicable to the excluded territory as provided by Chapter 321, Tax Code, but is applicable to the territory remaining in the district.