Sec. 26.09.  CALCULATION OF TAX.  (a)  On receipt of notice of the tax rate for the current tax year, the assessor for a taxing unit other than a county shall calculate the tax imposed on each property included on the appraisal roll for the unit.
(b)  The county assessor-collector shall add the properties and their values certified to him as provided by Chapter 24 of this code to the appraisal roll for county tax purposes.  The county assessor-collector shall use the appraisal roll certified to him as provided by Section 26.01 with the added properties and values to calculate county taxes.
(c)  The tax is calculated by:
(1)  subtracting from the appraised value of a property as shown on the appraisal roll for the unit the amount of any partial exemption allowed the property owner that applies to appraised value to determine net appraised value;
(2)  multiplying the net appraised value by the assessment ratio to determine assessed value;
(3)  subtracting from the assessed value the amount of any partial exemption allowed the property owner to determine taxable value;  and
(4)  multiplying the taxable value by the tax rate.
(c-1)  The assessor for a taxing unit shall calculate the amount of tax imposed by the taxing unit on property for the 2023 tax year as if the changes in law made by S.B. 2, Acts of the 88th Legislature, 2nd Called Session, 2023, were in effect for that tax year and also as if the changes in law made by that Act were not in effect for that tax year.  This subsection expires December 31, 2024.
(d)  If a property is subject to taxation for a prior year in which it escaped taxation, the assessor shall calculate the tax for each year separately.  In calculating the tax, the assessor shall use the assessment ratio and tax rate in effect in the unit for the year for which back taxes are being imposed.  Except as provided by Subsection (d-1), the amount of back taxes due incurs interest calculated at the rate provided by Section 33.01(c) from the date the tax would have become delinquent had the tax been imposed in the proper tax year.
(d-1)  For purposes of this subsection, an appraisal district has constructive notice of the presence of an improvement if a building permit for the improvement has been issued by an appropriate governmental entity.  Back taxes assessed under Subsection (d) on an improvement to real property do not incur interest if:
(1)  the land on which the improvement is located did not escape taxation in the year in which the improvement escaped taxation;
(2)  the appraisal district had actual or constructive notice of the presence of the improvement in the year in which the improvement escaped taxation; and
(3)  the property owner pays all back taxes due on the improvement not later than the 120th day after the date the tax bill for the back taxes on the improvement is sent.
(d-2)  For purposes of Subsection (d-1)(3), if an appeal under Chapter 41A or 42 relating to the taxes imposed on the omitted improvement is pending on the date prescribed by that subdivision, the property owner is considered to have paid the back taxes due by that date if the property owner pays the amount of taxes required by Section 41A.10 or 42.08, as applicable.
(e)  The assessor shall enter the amount of tax determined as provided by this section in the appraisal roll and submit it to the governing body of the unit for approval.  The appraisal roll with amounts of tax entered as approved by the governing body constitutes the unit's tax roll.
Acts 1979, 66th Leg., p. 2281, ch. 841, Sec. 1, eff. Jan. 1, 1982.  Amended by Acts 1981, 67th Leg., 1st C.S. p. 166, ch. 13, Sec. 121, eff. Jan. 1, 1982;  Acts 1983, 68th Leg., p. 4827, ch. 851, Sec. 19, eff. Aug. 29, 1983.
Amended by: 
Acts 2011, 82nd Leg., R.S., Ch. 138 (S.B. 551), Sec. 1, eff. September 1, 2011.
Acts 2015, 84th Leg., R.S., Ch. 465 (S.B. 1), Sec. 6, eff. June 15, 2015.
Acts 2023, 88th Leg., 2nd C.S., Ch. 1 (S.B. 2), Sec. 6.05, eff. July 22, 2023.