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Tax Records & Assessments in Illinois

    In Illinois, property tax is a primary source of funding for local governments, including counties, municipalities, school districts, libraries, park districts, and other special service areas. Property taxes are assessed and collected at the county level and are based on local property tax records and assessments.

    What Are Property Tax Records?

    Property tax records are public documents showing how much tax is owed based on the assessed values of properties, applicable exemptions, and local tax rates. These records are maintained by the county assessor, county treasurer, and county clerk. They typically include the following information:

    • Ownership Information: The names and the mailing address of the current legal owner of the property

    • Parcel Identification Number (PIN): The unique identifier assigned to each taxable property

    • Property Characteristics: Building square footage, year built, land area, and use type

    • Assessed Value: The value placed on the property by the assessor, which is a percentage of the property’s market value

    • Equalized Assessed Value (EAV): The assessed value multiplied by the state equalization factor to bring assessments to uniformity

    • Tax Exemptions: Any applied tax relief, such as the general homestead exemption, senior exemption, or disabled persons exemption

    • Tax Rate and Bills: Annual tax rates applied to the EAV and history of tax payments, delinquencies, and refunds

    What Is a Property Tax Assessment?

    A property tax assessment in Illinois is the process by which a local government official estimates the fair market value of a property and applies an assessment level to determine the assessed value. In most counties, residential property is assessed at 33.33% of market value (one-third), unless otherwise specified by classification statutes (for example, Cook County has different levels based on property class).

    How Property Assessments Work in Illinois

    Property assessments in Illinois are conducted by local township assessors or the county assessor’s office. Per law, all non-farm property must be viewed and revalued at least every four years (or every three years in Cook County).

    To determine value, assessors primarily use the Market Approach, which compares a property to similar homes that sold recently in the same neighborhood. They may also use the Cost Approach (calculating what it would cost to rebuild the home today minus depreciation) or the Income Approach for commercial properties.

    Since assessors manage thousands of parcels, they can also use mass appraisal techniques. These are statistical models that adjust values based on neighborhood-wide sales trends rather than inspecting every home individually each year.

    How Property Taxes Are Calculated in Illinois

    Property tax bills in Illinois are calculated using several factors, such as:

    • Fair Market Value: The assessor’s estimate of what the home would sell for.

    • Assessed Value: 33.33% of the market value (except in Cook County, where residential properties are assessed at 10%)

    • State Equalization Factor (Multiplier): A “multiplier” applied by the Illinois Department of Revenue to each county’s assessments to ensure uniformity across the state

    • Equalized Assessed Value (EAV): The assessed value multiplied by the equalization factor

    • Exemptions: Deductions (like the Homestead Exemption) are subtracted from the EAV

    • Tax Rate: The remaining taxable value multiplied by the combined tax rate (levied by your school, city, and county) to reach the final dollar amount due

    To calculate the tax, the fair market value is first divided by three to obtain the assessed value. Next, the assessed value is multiplied by the Equalization Factor less Exemptions to obtain the taxable assessed value.

    Finally, the tax bill = (equalized assessed value - exemptions) x local tax rate.

    What Affects Your Property’s Assessed Value?

    Certain value drivers are considered by assessors in estimating a property’s value. These include the following:

    • Physical Characteristics: Square footage, age, number of bedrooms/bathrooms, and basement finishing

    • Improvements: New decks, garages, or kitchen remodels

    • Location: Proximity to desirable schools, parks, or transit

    • Neighborhood Sales: Median sales price of similar homes nearby over the last three years

    Why Your Property Tax Bill Might Increase (or Decrease)

    While many people believe that taxes only go up when home values rise, in reality, a property tax bill can increase even if the home’s value remains the same. A property tax bill can increase or decrease due to the following:

    • Tax rate changes

    • Reassessments

    • Exemption changes

    How to Review Your Tax Assessment for Accuracy

    Homeowners often review their property report card annually. This document, available at the assessor’s office, lists the data used to value their homes. To review a tax assessment, check for:

    • Factual Errors: Check for incorrect square footage, number of bathrooms, or property class

    • Uniformity: Check if similar homes in your immediate area have significantly lower assessments

    • Market Alignment: Verify if the “fair market value” listed on your assessment notice is higher than what you can actually sell the home for today

    How to Appeal a Property Tax Assessment in Illinois

    If you find an error in your tax assessment or believe your home is overvalued, you can ask for a reassessment via the following options:

    • Informal Review: Many township assessors allow an informal meeting to correct simple data errors.

    • Board of Review: If a resolution is not reached, you can file a formal complaint with the County Board of Review. The grounds for appeal include incorrect market value, lack of assessment uniformity, and factual errors in property description. You must provide evidence, such as a recent appraisal or a list of comparable “comps” that sold for less.

    • State Level: If dissatisfied with the county’s decision, you can further appeal to the Illinois Property Tax Appeal Board (PTAB) or the circuit court.

    How to Find Property Tax Records & Assessments in Illinois

    Most counties in Illinois provide property tax records and assessments through an online treasurer or assessor portal. By entering a property’s address or its Property Index Number (PIN), you can view the current assessment, previous years’ tax bills, and whether the taxes are currently paid or delinquent. Alternatively, you can visit the county assessor’s office or the county treasurer’s office to submit an in-person request.

    FAQs

    Yes. Under state law, all assessment and tax payment records are public documents and are generally accessible through county websites.

    Market value is the price a buyer would pay today. In many Illinois jurisdictions, the assessed value is exactly 33.33% of that market value.

    General assessments occur every four years in most counties, while Cook County reassesses every three years on a rotating triennial cycle.

    Yes. Most county treasurer websites maintain at least a five-to-ten-year history of tax payments for every parcel.

    This usually happens because local taxing districts increased their tax levy, causing the local tax rate to rise even if property values remained stable.