70 ILCS 605/12-18

If for any reason the clerk of the court fails to give proper notice of the hearing on any report, petition or assessment roll, such failure shall not be grounds for dismissing the report, petition or roll, but the court shall continue the cause and direct that proper notice be given. Neither shall it be valid ground for objection on the part of any landowner that any other landowner has not received proper notice. If proper notice is given and any landowner fails to appear within the time specified or within any further time allowed him by the court, then a default may be taken against him in the same manner and with the same effect as in other civil proceedings.