(a) Not later than the 20th day after the date the person receives the notice sent under Section 248A.253, the person in writing may:
(1) accept the determination and recommended penalty of the department; or
(2) make a request for a hearing on the occurrence of the violation, the amount of the penalty, or both.
(b) If the person accepts the determination and recommended penalty or if the person fails to respond to the notice, the department by order shall approve the determination and impose the recommended penalty.