35 ILCS 200/21-10
In counties with 3,000,000 or more inhabitants, the county board may by resolution or ordinance require the County Auditor to prepare a delinquent property tax ledger system, or adopt such a system already prepared and give custody of the same to the County Auditor, in which all the delinquent taxes due upon the various properties in the county shall be listed under the legal description of each property provided that the resolution or ordinance of the county board in adopting the system shall provide that a Delinquent Property Tax Ledger shall be installed and maintained by the County Auditor. The ledger shall contain all unpaid general property taxes. The resolution or ordinance shall also provide that a Property Tax Docket shall be installed and maintained by the County Clerk. The docket shall contain and list all court proceedings which affect the general property taxes levied upon any property. The Property Tax Docket and the Property Tax Ledger shall be installed by the respective County Officers within 60 days from the date of the adoption of the ordinance or resolution by the county board. The ordinance or resolution shall prescribe the form and manner of maintenance of the system, which system may also include such other related matters as the ordinance or resolution requires. The ordinance or resolution may also provide for a similar system for delinquent special assessments in the office of the County Clerk. Upon the adoption of such a system by the county board, the County Clerk upon application shall issue a certificate stating the total amount of general taxes, special assessment taxes, interest, penalties and costs which are delinquent upon any property, or if none is delinquent, a statement to that effect. The certificate as issued by the County Clerk may contain such additional information as the resolution or ordinance of the county board adopting such a system requires. That part of the certificate issued by the County Clerk showing the amount of delinquent general property taxes due upon any property shall be certified to by the County Auditor or if none is delinquent, a certification by the County Auditor to that effect. The county board may provide a fee not to exceed $5 for each certificate to be paid to the County Clerk and shall provide that a portion of the fee shall be placed in an indemnity fund in the custody of the County Treasurer to indemnify any person, municipal corporation, quasi-municipal or district which may be damaged by reason of any erroneous certificate.
35 ILCS 200/21-10