Texas Tax Code - TAX § 191.087. Failure to File Report or Pay Tax

(a) If a person taxed under this subchapter fails to file a report required by this subchapter or to pay the tax imposed by this subchapter when due, the person forfeits five percent of the amount of tax due as a penalty. If the person then fails to file the report or pay the tax within 30 days after the day on which the tax or report is due, the person forfeits an additional penalty of five percent of the amount of the tax.

(b) The minimum penalty imposed by this section is $1.