Ill. Admin. Code tit. 35 § 1100.411
An application for the renewal of a permit must be filed with the Agency at least 90 days prior to the expiration date of the existing permit.
When a permittee has made timely and sufficient application for the renewal of a permit, the existing permit must continue in full force and effect until the final Agency decision on the application has been made and any final Board decision on any appeal pursuant to Section 40 has been made unless a later date is fixed by order of a reviewing court. (See Section 10-65 of the Illinois Administrative Procedure Act [5 ILCS 100/10-65] .)
The owner or operator must submit only the information required under Subpart C of this Part that has changed since the last permit review by the Agency. The application for renewal must be signed in accordance with the signature requirements of Section 1100.303 of this Part.
Applications for permit renewal are subject to all requirements and time schedules in Sections 1100.402 through 1100.409 of this Part.
Ill. Admin. Code tit. 35, § 1100.411