Ill. Admin. Code tit. 56, § 200.500 – Filing a Complaint

a) An employee may file a complaint with the Department alleging a violation of the Act by completing and submitting a form provided by the Department and submitting supporting documentation. All complaints shall be filed within 3 years after the alleged violation. [820 ILCS 192/30]
b) The Department has the power to conduct investigations upon receipt of a complaint or at the discretion of the Director. Complaints shall be reviewed by the Department to determine whether there is cause for investigation.
c) The Department may attempt to resolve the complaint by conference, voluntary mediation, conciliation, or persuasion.
d) If, after investigation, the Department believes that the Act has been violated, then the Department shall notify the parties in writing and the matter shall be referred to an administrative hearing consistent with Section 200.520.