Maturity of tax — interest — penalty.

All taxes not paid within the time prescribed in this chapter are subject to a penalty as provided in section 421.27 and shall draw interest at the rate in effect under section 421.7 until paid. [S13, §1481-a23; C24, 27, 31, 35, 39, § 7368; C46, 50, 54, 58, 62, 66, 71, 73, 75, 77, 79, 81, §450.63 ; 81 Acts, ch 131, §16 , ch 147, §11, 20 ; 82 Acts, ch 1180, §7, 8 ] 84 Acts, ch 1173, §9 ; 86 Acts, ch 1007, §39 ; 90 Acts, ch 1172, §13