Local Government Code §336.023

(a) A district may call an election to approve one or both of the following: (1) a sales tax; or (2) an ad valorem tax on property in the district. (b) A sales tax and an ad valorem tax may be approved at the same election. (c) Before a district may call the first election under this section, the lead governmental entity by resolution must set: (1) the date of the election; and (2) the type and rate of each tax that will appear on the ballot proposition under Section 336.027 .