65 ILCS 5/9-2-81
In cities of this state having a population of 1,000,000 or more, when any officer is authorized to collect special assessments or special taxes, that officer, on or before March 10 each year, or if the general tax books have not been turned over to the county collector at that time then within 15 days after the county collector has received the general tax books, shall mark on the general tax books of the county collector, opposite the description of all lots, blocks, tracts, or parcels of land to be assessed, the number of the special assessment or special tax warrant. The county collector shall stamp or write in large letters on the face of all tax bills or receipts issued by him the number of the special assessment or special tax warrant, and the words, "Special assessment due and payable."
65 ILCS 5/9-2-81