All of us in Illinois are asking this question. I just attended a Women's Council of Realtors Lunch Meeting where the speakers were the Lake County Assessor and the Assistant Cook County Assessor. I learned a great deal.
The assessors office in both Lake and Cook County is interested in determining the "Fair Cash Value" not the "Market Value" of a home. The equalization factor is determined by local township assessors in Lake County and there is not limit on the tax rate in a Home Rule Community. Riverwoods is a home rule community.
Both assessors said the tax rate is computed based on 2 factors. 1. The current assessment value 2. The tax district levy request from the taxing district. When you appeal your taxes you are not protesting your taxes you are appealing the value of your property. Talk about value, not taxes. Property tax is not like sales tax. The value of your home can go down, but your taxes stay the same since the government needs a certain amount of money to operate. The assessors job is to spread the burden fairly.
Lake County, Illinois reassesses every 4 years and Cook County reassesses every 3 years (1/3 of all properties every 3 years).
They explained that your taxes could be higher than your next door neighbor in the same house because of exemptions. There are 5 kinds of exemptions:
1. Homestead exemptions $6,000 in assessed value per person.
2. Senior Citizen exemption- one household member must be 65 or older. Cook County must reapply every year.
3. Senior Freeze exemption- total household income of $55,000 or less + age 65.
4. Home Improvement Exemption-spread tax increase due to major improvement of property over several years.
5. Disabled Veterans exemption
6. Long Term Home Owner Exemption- Only in Cook County.
They mentioned a new website: Cookcountypropertyinfo.com
This is pretty technical, but I thought it was worth explaining. I felt I learned a lot.