Texas Tax Code - TAX § 11.01. Real and Tangible Personal Property

(a) All real and tangible personal property that this state has jurisdiction to tax is taxable unless exempt by law.

(b) This state has jurisdiction to tax real property if located in this state.

(c) This state has jurisdiction to tax tangible personal property if the property is:

(d) Tangible personal property that is operated or located exclusively outside this state during the year preceding the tax year and on January 1 of the tax year is not taxable in this state.

(e) For purposes of Subsection (c)(3), property is considered to be used continually, whether regularly or irregularly, in this state if the property is used in this state three or more times on regular routes or for three or more completed assignments occurring in close succession throughout the year.  For purposes of this subsection, a series of events are considered to occur in close succession throughout the year if they occur in sequence within a short period at intervals from the beginning to the end of the year.