Section 181.003 - Payment of Tax(a) The person on whom the tax is imposed by this chapter shall pay the tax to the comptroller at the comptroller's Austin office.(b) The tax payment is due on the 25th day of each month, and the amount of the tax is computed on the amount of business done during the preceding month by the person on whom the tax is imposed. Acts 1981, 67th Leg., p. 1711, ch. 389, Sec. 1, eff. Jan. 1, 1982.