Texas Tax Code - TAX § 111.0081. When Payment Is Required

(a) Except as provided in Subsections (b) and (c) of this section, the amount of a determination made under this code is due and payable 10 days after it becomes final. If the amount of the determination is not paid within 10 days after the day it became final, a penalty of 10 percent of the amount of the determination, exclusive of penalties and interest, shall be added.

(b) This section does not apply to a determination under Section 111.022.

(c) The amount of a determination made under this code is due and payable 20 days after a comptroller's decision in a redetermination hearing becomes final. If the amount of the determination is not paid within 20 days after the day the decision became final, a penalty of 10 percent of the amount of the determination, exclusive of penalties and interest, shall be added.