The primary role of the Assessor is to estimate the property value of 1.7 million parcels of real estate in Cook County. The value of these properties is not determined on an individual basis, but rather by a mass appraisal system. The mass appraisal system is a way to put fairness into the entire assessment process.

Reassessment of property in Cook County is done within a triennial cycle, meaning it occurs every three years.  The Cook County Assessor’s Office alternates reassessments between the north and west suburbs, the south and west suburbs and the City of Chicago.

To determine the property value of a single family home, the Assessor’s Office uses a computer assisted technique called multiple regression. This technique creates a type of sales comparison average, a mathematical relationship between the value of your house and those of your neighbors. It is important to note that while a property’s sale price may often reflect a property’s value, sale price does not always equal property value, due to such extraneous considerations as the type of financing and the inclusion of personal property. The key concern in property assessment is uniformity. The rule of uniformity requires that property be valued equally with property of like kind. The sales comparison approach ensures that similar properties are assessed similarly.

The assessment for residential properties, (single family homes to apartment buildings with less than seven apartments), is sixteen percent of the current property value; a figure based on land, building, and neighborhood characteristics, as well as sales data.

An integral part of the assessment process is the collection of data on economic and neighborhood trends and developments. One use of this data is to define neighborhoods which have similar housing types and sale prices. These ‘assessment neighborhoods’ are mapped and assigned neighborhood codes, a necessary component of the multiple regression process used to give preliminary values to the county’s nearly 1.3 million residential properties. In suburban townships or Chicago neighborhoods which will undergo triennial reassessment, Assessor’s Office staff meet with local elected officials, community leaders, real estate professionals and other citizens knowledgeable about real estate in the area, to verify or correct assessment neighborhood boundaries before they are finalized. Assessor Houlihan attends these meetings as a means to understand what local citizens perceive to be the forces at work in their communities’ property values.

It is understandable that a small percentage of individual properties will need further review. Homeowners generally file appeals themselves, and their first contact is with the Taxpayer Services Department. Friendly, informative service is the aim of Taxpayers Services Department. If taxpayers are not satisfied with the results of their appeals, they are encouraged to contact the Assessor’s Taxpayer Advocate Department, which will conduct an individualized re-review of an appeal.

The tax cycle begins with the…

Cook County Assessor - The Cook County Assessor places a property value on close to 1.7 million parcels in Cook County. Each year, one third of the property in Cook County is reassessed.

Board of Review - The Cook County Board of Review hears complaints and determines those property values.

Department of Revenue - The Illinois Department of Revenue analyzes the assessments in every county throughout the state and determines the State Equalization Factor Multiplier. This factor is then applied to those counties’ assessments which fall below the statutory 33 1/3% level of property value.

County Clerk - The Cook County Clerk reviews the municipalities’ budgets and determines the tax rates that should be applied to the assessments based on the estimated expenditures for each unit of local government.

County Treasurer - The Cook County Treasurer calculates the tax bills, mails them out, and collects the tax dollars.