Iowa Code § 294.1
No person shall be employed as a teacher in a common school without having a certificate issued by some officer duly authorized by law.
No compensation shall be recovered by a teacher for services rendered while without such certificate.
[R60, §2062; C73, §1758; C97, §2788; C24, 27, 31, 35, 39, §4336; C46, 50, 54, 58, 62, 66, 71, 73, 75, 77, 79, 81, §294.1]