Tex. Tax Code § 26.13: TAXING UNIT CONSOLIDATION DURING TAX YEAR.

(a) If two or more taxing units consolidate into a single taxing unit after January 1, the governing body of the consolidated unit may elect to impose taxes for the current tax year either as if the unit as consolidated had existed on January 1 or as if the consolidation had not occurred.

(b) The chief appraiser shall prepare and deliver an appraisal roll for the unit or units in accordance with the election made by the governing body.

(c) Whatever the election, the assessor and collector for the unit, as consolidated shall assess and collect taxes on property that is taxable by the unit as consolidated.

Acts 1979, 66th Leg., p. 2283, ch. 841, Sec. 1, eff. Jan. 1, 1982.