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Collar Counties 101: DuPage, Lake, Kane, McHenry, & Will

DuPage, Lake, Kane, McHenry, and Will Counties are known as the collar counties because they encircle Cook County, forming a so-called “collar”.

Each of these counties has a Chief County Assessor’s Office, as well as an assessor for each township.

Collar counties also have their own reassessment timeline that differ from Cook County’s triennial schedule. In the collar counties, reassessment occurs every four years.

The Assessor’s Office is responsible for estimating the market value of each parcel of property within county limits. Then they apply an assessment percentage to their value to calculate the assessment.

In Collar counties, all properties are assessed at 1/3 of their estimated market value. An increased assessment will directly impact property tax expenses. A larger assessment means a more expensive real estate tax bill.

Some cities are split between Cook County and a Collar County. For example, if you live in Barrington, IL, your assessment could be different from your neighbor’s assessment. It depends on whether your property is on located in the Lake County side or the Cook County side of Barrington.

Can I contest my assessment?

Yes. It doesn’t matter if your tax bill increased, decreased, or remained the same. You can challenge the amount of the assessment the tax bill is based on.

Success of a tax appeal depends on several factors. The market value estimate that an Assessor assigns to a property cannot exceed its actual market value. If an appraisal or recent sale price demonstrates that the actual value is lower than the assessed value, the taxpayer should be able to obtain a reduction.

Assessments must also follow the rule of uniformity where comparable properties should have comparable assessments. If the property owner can demonstrate that similar properties have lower assessments, then the assessment is in violation of the rule of uniformity and can be reduced.

What is the property tax appeal process?

Deadlines, complaint forms, evidence, and rules of practice can vary in DuPage, Lake, Kane, McHenry, and Will Counties. You should contact the respective collar county assessor’s office to make sure you have all the information you need.

Appeals can become complicated and involve multiple levels of review. Documentation and data must be prepared and filed before specific county deadlines to substantiate the appeal.

Some of the information you may need to obtain and provide in a formal appeal can include:

  • Property record cards
  • Evidence of unfair assessment
  • Property photographs
  • Property appraisal
  • Evidence of Recent sales of comparable properties
  • Fair market value details
  • Prevailing assessment levels in the respective district

Due to all the formal guidelines that must be followed, some collar county homeowners hire a tax attorney to represent them in the process.

Property taxes unappealing…we can help!

Appealing your property taxes is one way to ensure that the amount you pay is fair whether you live in Cook County or any of the collar counties of DuPage, Lake, Kane, McHenry, and Will.

At present, Illinois is second only to New Jersey with the highest effective property tax rates in the United States. Cook County residents saw a 10% increase to the average 2017 property tax bill with suburban tax increases coming in as high as 6.5%. 2018 also saw property tax increases throughout the Chicagoland area.

Staying on top of your assessment notices and researching local appeal procedures can help homeowners avoid being overburdened with property taxes.

Appeal.Tax can prepare your property tax appeal and handle it from start to finish. There is no fee unless a reduction is obtained. And we only charge a small portion of the overall tax savings secured. 

Since 2015, we’ve saved Illinois property owners over $100 million in reduced property taxes.

Contact Appeal.Tax today to discuss your Association, residential, or commercial property tax appeal. Tax Attorney Timothy Jacobs can be reached at 847-777-7270 or

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