(220 ILCS 5/10-201) (from Ch. 111 2/3, par. 10-201)
    Sec. 10-201. (a) Jurisdiction. Within 35 days from the date that a copy of the order or decision sought to be reviewed was served upon the party affected by any order or decision of the Commission refusing an application for a rehearing of any rule, regulation, order or decision of the Commission, including any order granting or denying interim rate relief, or within 35 days from the date that a copy of the order or decision sought to be reviewed was served upon the party affected by any final order or decision of the Commission upon and after a rehearing of any rule, regulation, order or decision of the Commission, including any order granting or denying interim rate relief, any person or corporation affected by such rule, regulation, order or decision, may appeal to the appellate court of the judicial district in which the subject matter of the hearing is situated, or if the subject matter of the hearing is situated in more than one district, then of any one of such districts, for the purpose of having the reasonableness or lawfulness of the rule, regulation, order or decision inquired into and determined.
    The court first acquiring jurisdiction of any appeal from any rule, regulation, order or decision shall have and retain jurisdiction of such appeal and of all further appeals from the same rule, regulation, order or decision until such appeal is disposed of in such appellate court.
    (b) Pleadings and record. No proceeding to contest any rule, regulation, decision or order which the Commission is authorized to issue without a hearing and has so issued shall be brought in any court unless application shall have been first made to the Commission for a hearing thereon and until after such application has been acted upon by the Commission, nor shall any person or corporation in any court urge or rely upon any grounds not set forth in such application for a hearing before the Commission, but the Commission shall decide the questions presented by the application with all possible expedition consistent with the duties of the Commission. The party taking such an appeal shall file with the Commission written notice of the appeal. The Commission, upon the filing of such notice of appeal, shall, within 5 days thereafter, file with the clerk of the appellate court to which such appeal is taken a certified copy of the order appealed. The Commission shall prepare a copy of the transcript of the evidence, including exhibits and transcripts of Commission meetings prepared in accordance with Section 10-102 of this Act, or any portion of the record designated in a stipulation that only certain questions are involved on appeal, which stipulation is to be included in the record provided for in Section 10-110. The Commission shall certify the record and file the same with the clerk of the appellate court to which such appeal is taken within 35 days of the filing of the notice of appeal. The party serving such notice of appeal shall, within 5 days after the service of such notice upon the Commission, file a copy of the notice, with proof of service, with the clerk of the court to which such appeal is taken, and thereupon the appellate court shall have jurisdiction over the appeal. The appeal shall be heard according to the rules governing other civil cases, so far as the same are applicable.
    (c) No appellate court shall permit a party affected by any rule, regulation, order or decision of the Commission to intervene or become a party plaintiff or appellant in such court who has not taken an appeal from such rule, regulation, order or decision in the manner as herein provided.
    (d) No new or additional evidence may be introduced in any proceeding upon appeal from a rule, regulation, order or decision of the Commission, issued or confirmed after a hearing, but the appeal shall be heard on the record of the Commission as certified by it. The findings and conclusions of the Commission on questions of fact shall be held prima facie to be true and as found by the Commission; rules, regulations, orders or decisions of the Commission shall be held to be prima facie reasonable, and the burden of proof upon all issues raised by the appeal shall be upon the person or corporation appealing from such rules, regulations, orders or decisions.
    (e) Powers and duties of reviewing court:
        (i) An appellate court to which any such appeal is
    
taken shall have the power, and it shall be its duty, to hear and determine such appeal with all convenient speed. Any proceeding in any court in this State directly affecting a rule, regulation, order or decision of the Commission, or to which the Commission is a party, shall have priority in hearing and determination over all other civil proceedings pending in such court, excepting election contests.
        (ii) If it appears that the Commission failed to
    
receive evidence properly proffered, on a hearing or a rehearing, or an application therefor, the court shall remand the case, in whole or in part, to the Commission with instructions to receive the testimony so proffered and rejected, and to enter a new order based upon the evidence theretofore taken, and such new evidence as it is directed to receive, unless it shall appear that such new evidence would not be controlling, in which case the court shall so find in its order. If the court remands only part of the Commission's rule, regulation, order or decision, it shall determine without delay the lawfulness and reasonableness of any independent portions of the rule, regulation, order or decision subject to appeal.
        (iii) If the court determines that the Commission's
    
rule, regulation, order or decision does not contain findings or analysis sufficient to allow an informed judicial review thereof, the court shall remand the rule, regulation, order or decision, in whole or in part, with instructions to the Commission to make the necessary findings or analysis.
        (iv) The court shall reverse a Commission rule,
    
regulation, order or decision, in whole or in part, if it finds that:
            A. The findings of the Commission are not
        
supported by substantial evidence based on the entire record of evidence presented to or before the Commission for and against such rule, regulation, order or decision; or
            B. The rule, regulation, order or decision is
        
without the jurisdiction of the Commission; or
            C. The rule, regulation, order or decision is in
        
violation of the State or federal constitution or laws; or
            D. The proceedings or manner by which the
        
Commission considered and decided its rule, regulation, order or decision were in violation of the State or federal constitution or laws, to the prejudice of the appellant.
        (v) The court may affirm or reverse the rule,
    
regulation, order or decision of the Commission in whole or in part, or remand the decision in whole or in part where a hearing has been held before the Commission, and state the questions requiring further hearings or proceedings and give such other instructions as may be proper.
        (vi) When the court remands a rule, regulation, order
    
or decision of the Commission, in whole or in part, the Commission shall enter its final order with respect to the remanded rule, regulation, order or decision no later than 6 months after the date of issuance of the court's mandate. The Commission shall enter its final order, with respect to any remanded matter pending before it on the effective date of this amendatory Act of 1988, no later than 6 months after the effective date of this amendatory Act of 1988. However, when the court mandates, or grants an extension of time which the court determines to be necessary for, the taking of additional evidence, the Commission shall enter an interim order within 6 months after the issuance of the mandate (or within 6 months after the effective date of this amendatory Act of 1988 in the case of a remanded matter pending before it on the effective date of this amendatory Act of 1988), and the Commission shall enter its final order within 5 months after the date the interim order was entered.
    (f) When no appeal is taken from a rule, regulation, order or decision of the Commission, as herein provided, parties affected by such rule, regulation, order or decision, shall be deemed to have waived the right to have the merits of the controversy reviewed by a court and there shall be no trial of the merits of any controversy in which such rule, regulation, order or decision was made, by any court to which application may be made for the enforcement of the same, or in any other judicial proceedings.
(Source: P.A. 100-840, eff. 8-13-18.)