Article 8(b) requires all real property and tangible personal property in the State of Texas, unless exempt as required or permitted by the Constitution, whether owned by natural persons or corporations, other than municipal, shall be taxed in proportion to its value, which shall be ascertained as may be provided by law.
Property Tax Code
Section 23.01 requires all taxable properties, with a few exceptions, to be appraised at market value as of January 1. As defined, Market value is the price at which a property would transfer for cash or its equivalent under prevailing market conditions.
An example of an exception is the valuation of qualified 1-d-1 agricultural land. It is valued based on productivity value.
Section 26.02 states that the assessment of property for taxation on the basis of a percentage of its appraised value is prohibited. All property shall be assessed on the basis of 100 percent of its appraised value.