225 ILCS 725/6.1
When the applicant has complied with all applicable provisions of this Act and the rules of the Department, the Department shall issue the permit. All applications for a permit submitted to the Department shall either be granted, denied, or a deficiency letter issued in writing within 20 business days after the date of receipt by the Department, unless the applicant and Department mutually agree to extend the 20-day period. If granted, the written permit shall be issued. If a deficiency letter is issued , the Department shall provide specific requirements for additional information or documentation needed for the application to be considered and the permit issued. Upon submission of the required information and documentation, the same process and timeframe as provided in this Section shall continue until either the permit is issued or it is determined that the permit cannot be issued because of legal or regulatory impediments. The Department shall respond in a timely manner to any application or submission of additional information and documentation after initial submission.
225 ILCS 725/6.1