(a) A district by order may impose a sales and use tax under this chapter to finance the operations of the district only if the tax is approved at an election held under Section 387.003.
(b) A district may not adopt a sales and use tax under this chapter if the adoption of the tax would result in a combined tax rate of all local sales and use taxes that would exceed the maximum combined rate prescribed by Sections 321.101 and 323.101, Tax Code, in any location in the district.