The Cook County Assessor’s primary responsibility is to list, describe and value more than 1.8 million parcels of property. The Assessor also administers many exemption and incentive programs.

The Assessor’s Office distributes a wide variety of literature and informational pieces to educate individuals and groups about the assessment process. The Assessor’s staff is also trained to help property owners understand their assessments and file appeals.

In general, any reduction made on your assessment will be reflected on your second installment tax bill, along with any exemptions for which you have applied and qualified. However, if your Certificate of Error was approved by the circuit court or certified by the Assessor's Office to the Treasurer before November 30 of the prior year, you should receive an estimated tax bill that reflects the corrected assessed value shown on your Certificate of Error.

It is possible for your mortgage company to increase your monthly escrow payment due to an increase in real estate taxes. Property taxes can increase due to a reassessment, an increase in your local tax rate or an increase in the state equalization factor. The state equalization factor (often called the “multiplier”) is applied by the Illinois Department of Revenue to all property in Cook County to equalize assessments throughout the state. You should call the Assessor’s Office at (312) 443-7550 to be sure you are receiving all the property tax exemptions for which you are entitled.

Always check the PIN on your bill against the PIN(s) on your sale or mortgage documents to make sure that the bill matches the property that you own.

There are two reasons a home may receive more than one tax bill:

First, it is not uncommon for a residence to sit on more than one parcel of land, each with its own Property Index Number (PIN). A bill is issued for each PIN. If your home straddles two PINs, then the home value will be split between the PINs.

The current tax bill can be obtained from the Cook County Treasurer’s Office. Tax bills for previous years are handled by the Cook County Clerk’s Office. The Treasurer’s phone number is (312) 443-5100 and the County Clerk’s phone number is (312) 603-5656. To receive a duplicate of the current tax bill by mail, you may also visit the Treasurer’s Web site at www.cookcountytreasurer.com.

You should have your name on the tax bill. Our office mails out reassessment notices and exemption applications to the name and address on the bill. Names and addresses are maintained by the Cook County Treasurer’s Office. Generally, most mortgage companies get your tax bill from the Treasurer’s Office electronically.

Your property tax bill represents your share of the budgets approved by local taxing bodies for their operations. Property taxes are one of the main sources of funding for local government services, such as park districts, fire districts and especially public education. If you believe your taxes are too high, you should:

Calculating an Estimated Residential Property Tax Bill

The Cook County Assessor is responsible for determining the first part of the equation used by the Cook County Treasurer to calculate your property taxes. The Assessor does not set tax rates or levies or decide the dollar amount of your tax bill. He determines only a "Market Value" (MV) for your property and, for taxation, uses 10% of its value as the "Assessed Valuation" (AV).

A Real Estate Certificate of Error (C of E) allows the Cook County Assessor to change a property’s assessed value for a prior year. Illinois law provides this procedure as a way to correct a tax bill after the assessment for that tax year is finalized. A Certificate of Error addresses a single year. If you are entitled to a value reduction for more than one year, a Certificate of Error request must be filed for each individual year.

In Cook County, properties are classified based on their use. For example, apartment buildings over six units are classified as Class 3 properties. Class 5 properties are properties that are used for commercial or industrial purposes.

A property is used for commercial purposes if it is used primarily for buying and selling goods and services, or for otherwise providing goods and services. Commercial use includes real estate used for hotel, motel and apartment buildings of more than six units.