Key Word Definitions

Collar Counties


The Township Assessor is the elected official responsible for establishing the assessed valuation for all parcels of real estate in the Township. In the collar counties no complaint is filed before the Assessor.

Assessed Valuation/ Assessment Factor

The total valuation promulgated by the Assessor which includes an assessment for the land (the total site area) and the improvements located upon the site. In counties outside of Cook, the assessment is based on 33.33% of the property’s market value as determined by the Assessor or Board of Review.

Board of Review

An administrative body headed by three appointed Commissioners which, pursuant to a timely filed complaint, reviews/revises assessments promulgated by the Assessor.

Certificate of Error

A procedure allowing a taxpayer to apply for a partial refund of a paid tax bill based upon the over assessment of the property due to certain unusual circumstances. This procedure is generally available for only one prior year’s taxes and requires various administrative and/or judicial approval.

Illinois Property Tax Appeal Board

A state administrative body composed of five members appointed by the Governor which, pursuant to a timely filed complaint, reviews/revises assessments as determined by County Boards of Review throughout the state. The filing of a Board of Review complaint contesting the assessment is a prerequisite to filing a complaint before the Illinois Property Tax Appeal Board. If successful a portion of the tax will be refunded.

Local Tax Rate

The taxing districts (municipality, schools, park districts, police and fire departments, etc.) within each county submit their budgetary requests to the County Clerk each year. These districts are all enumerated on the tax bill. When the assessments for the entire County are finalized by the Assessor and Board of Review, and the State Equalizer has been formulated, a tax rate to meet those budgetary requests is promulgated.

State Equalizer

Each year the Illinois Department of Revenue reviews the total assessed valuation of each county and examines assessments made by the local assessors to determine whether or not the assessments are based on an accurate analysis of real estate values within the county.  If it is determined that the assessments are lower than values would indicate an “equalization” factor is developed by the state which then is made applicable to all property in a specific township.