Texas Tax Code - TAX § 311.012. Determination of Amount of Tax Increment

(a) The amount of a taxing unit's tax increment for a year is the amount of property taxes levied and assessed by the unit for that year on the captured appraised value of real property taxable by the unit and located in a reinvestment zone or the amount of property taxes levied and collected by the unit for that year on the captured appraised value of real property taxable by the unit and located in a reinvestment zone. The governing body of a taxing unit shall determine which of the methods specified by this subsection is used to calculate the amount of the unit's tax increment.

(b) The captured appraised value of real property taxable by a taxing unit for a year is the total taxable value of all real property taxable by the unit and located in a reinvestment zone for that year less the tax increment base of the unit.

(c) The tax increment base of a taxing unit is the total taxable value of all real property taxable by the unit and located in a reinvestment zone for the year in which the zone was designated under this chapter. If the boundaries of a zone are enlarged, the tax increment base is increased by the taxable value of the real property added to the zone for the year in which the property was added. If the boundaries of a zone are reduced, the tax increment base is reduced by the taxable value of the real property removed from the zone for the year in which the property was originally included in the zone's boundaries. If the municipality that designates a zone does not levy an ad valorem tax in the year in which the zone is designated, the tax increment base is determined by the appraisal district in which the zone is located using assumptions regarding exemptions and other relevant information provided to the appraisal district by the municipality.