55 ILCS 5/5-1068
A county board may expend monies for the preparation, establishment and maintenance of a detailed property record system which would provide information useful to assessment officials. Such detailed property record system shall be available to all assessing officials.
The county board may enter into contracts with persons, firms or corporations for the preparation and establishment of such record system.
The detailed property record system shall include up-to-date and complete tax maps except where these are otherwise already available or ordered, ownership lists, valuation standards, property record cards, including appraisals, for all or any part of the property in the county in accordance with reasonable rules and procedures prescribed by the Department of Revenue, but such system and records shall not be considered to be assessments nor limit the powers and duties of assessing officials, except that when any reappraisal of property is made and included in such record system, such assessing officials shall use the reappraisal value as a basis for assessment purposes.
The expense of the preparation, establishment and maintenance of a detailed property record system shall be borne by the county.
55 ILCS 5/5-1068