Texas Tax Code - TAX § 181.104. Penalty

(a) A person on whom the tax is imposed by this chapter and who fails to file a report as required by this chapter or does not pay the tax when it is due forfeits to the state a penalty of five percent of the amount of tax delinquent.

(b) If the report required by this chapter is not filed or the tax imposed by this chapter is not paid within 30 days after it is due, the person on whom the tax is imposed forfeits to the state a penalty of an additional five percent of the amount of tax delinquent.

(c) The minimum penalty under this section is $1.