70 ILCS 3455/65

The validity of a district created, district plan established, or transaction charge imposed under this Act may not be contested in any action or proceeding unless the action or proceeding is commenced within 30 days after the formation ordinance is adopted or, with respect to modifications to a district plan, within 30 days after a district plan has been modified. If a party appeals a final judgment, the party filing the appeal shall request discretionary acceleration under Supreme Court Rule 311(b).