Property taxes are determined by two primary factors. The first factor is the amount of money needed by the various taxing bodies (i.e. school districts, city and county taxes, fire departments, park districts, etc.). Once the assessments for a particular area are completed, these taxing bodies request money -- funds known as a levy.
The Cook County Clerk's Office uses the levy to calculate the tax rate, which in turn is used to determine your portion of the taxes. The geographic area where your property is located is categorized and given a tax code. Each and every property in a specific tax code (which can be several blocks or a few square miles) is taxed at the same rate.
The second primary factor determining your property tax bill is the assessment base, or the number of taxable properties in a tax code. To determine the tax rate for your property, the Clerk's Office takes divides the levy by the assessment base. This percentage then becomes the rate at which you are taxed.
The primary issue to remember about tax rates is that they are affected by the spending patterns of the various taxing bodies. The more money needed by the park district, the school district, police department and other taxing bodies, the higher your property taxes.