Original Equalized Assessment Valuations or EAV amounts of school district property are reported annually by the Illinois Department of Revenue (IDOR). There are four categories of changes to those original reported values that can alter EAV amounts. IDOR reports Enterprise Zone Abatements, General Authority Abatements and Property Tax Appeals Board decisions to ISBE. Districts directly report Certificates of Error to ISBE for the most current tax year and six prior years. That is accomplished by completing the forms listed on this page in cooperation with County Clerks.
This page provides information about the four types of EAV change, historical information about prior EAV change amounts and user tools that explain how abatements are calculated.
FY 25 Certificates of Error
Please note that the FY 25 Certificates of Error History report will be posted in this location soon. You must have the values that will be included in that report before you can complete the prior year submissions column in the FY 26 summary spreadsheet.