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The Cook County property tax system involves multiple agencies working together. They include:
Cook County Assessor's Office
Cook County Board of Review
Cook County Clerk
Cook County Treasurer
Illinois Department of Revenue
Local Governments
Local taxing districts and government agencies use property taxes to raise the revenue needed to cover annual budget needs. When the tax base is fair, the tax levy is fairly divided between property owners in that tax base.
Think of it like a pie: Local taxing districts create the pie (which can grow or shrink), and the property owners each pay for their piece of the pie according to each property’s share of the tax base.
Local Governments Set Revenue Goals
Local taxing agencies such as schools or park districts decide how much total revenue they need to raise from property taxes in their district each year. Each local government then passes a levy — an ordinance or resolution for this amount. These levies are filed with the Cook County Clerk. Levies are the first piece of the property tax rate equation.
CCAO Assigns Assessed Values and Processes Appeals
Another important piece of the property tax rate equation is the tax base: the total taxable value of all property in that district. The Assessor’s Office assigns values to all property in Cook County.
The tax base is also affected by homeowner exemptions, or property savings if property owners meet certain eligibility requirements. Our office oversees the exemption process. Property owners can file an appeal with the Assessor’s Office and the Cook County Board of Review if they disagree with their assessment.
The levy divided by the tax base determines the tax rate.
Illinois Department of Revenue Applies Equalization Factor
Once the assessed value of an area is set, the Illinois Department of Revenue applies an annual equalization factor. This factor is the same for all properties in Cook County. This factor, often called the multiplier, brings all properties to the 33.3% level required by law, transforming assessed values into equalized assessed values.
Equalized assessed values, minus exemption deductions, are the taxable value
of a property — what the tax rate is applied to.
Cook County Clerk Calculates Property Tax Rates
After our office determines property values, the Cook County Clerk uses this information to calculate property tax rates for each agency. They do this by dividing each agency’s levy by its tax base. The Clerk then calculates the local cumulative tax rate, adding up the tax rates of all agencies that levy taxes from the property owner.
Each individual property’s tax bill is calculated by multiplying
its taxable value (Equalized Assessed Value) by its local cumulative tax rate.
Cook County Treasurer Bills and Collects Property Tax Payments
The Cook County Treasurer then sends out tax bills and collects payments from property owners. Bills are issued in two installments each year.