Iowa Code § 166.14: Revocation by department.

Such a permit may also be revoked by the department at any time after a reasonable notice and hearing:

1. For violation of the terms, conditions, and requirements on which it was issued.

2. For violation of any law, or of any rule of the department, relating to the business authorized by such permit.

3. In case of a dealer’s permit, when a judgment has been rendered on the bond, or when the security of such bond has become impaired in any other way and no new bond is given as required by the department.