(a) If authorized at an election held in accordance with § 3890.210, the district may impose an annual operation and maintenance tax on taxable property in the district in accordance with § 49.107, Water Code, for any district purpose, including to:
(1) maintain and operate the district;
(2) construct or acquire improvements; or
(3) provide a service.
(b) The board shall determine the tax rate. The rate may not exceed the rate approved at the election.