Tex. Local Government Code § 504.257

(a) At an election held under Section 504.251 or 504.258, the authorizing municipality may also allow the voters to vote on a ballot proposition to limit the period for imposition of a sales and use tax. If an authorizing municipality elects to limit the period for imposition of the tax, the following phrase shall be added to the end of the ballot proposition prescribed by Section 504.256: "to be imposed for __________ years" (the number of years to be inserted as appropriate). The governing body of the municipality shall set the expiration date of the proposed tax to occur on the appropriate anniversary of the effective date of the tax.

(b) A sales and use tax imposed for a limited period under this section expires on the date set by the governing body of the authorizing municipality under Subsection (a) unless the tax is repealed on an earlier date by a majority of the voters voting in an election held in the municipality. If an election to abolish the tax is held, Sections 321.102(a) and 321.402(b), Tax Code, apply to the date of repeal.

(c) If an authorizing municipality reduces the rate of an additional sales and use tax under Chapter 321, Tax Code, to impose a tax under this chapter for a limited period as provided by this section, and the municipality does not have an election to change the rate of the additional sales and use tax before the tax under this chapter expires, on the date the tax under this chapter expires, the rate of the municipality's additional sales and use tax returns to the rate in effect immediately before the tax under this chapter was adopted. The municipality is not required to hold an election under Chapter 321, Tax Code, to impose the additional sales and use tax at that rate.

(d) A sales and use tax that is approved without limiting the period during which the tax is imposed remains in effect until repealed by election.

(e) An authorizing municipality that has imposed a tax under this chapter may extend the period of the tax's imposition or reimpose the tax only if the extension or reimposition is approved by a majority of the voters of the municipality voting at an election held for that purpose.