How to Lower Property Taxes in Illinois
An Illinois property tax bill has two levers you can pull: the exemptions subtracted from your assessment, and the assessment itself. Most people only think about the second. The first is often the fastest money, and in Cook County it can still be claimed for past years.
We are a research tool, not attorneys or a tax firm. The Cook County details below come from the Cook County Assessor's exemption pages, opened on October 30, 2026. Other Illinois counties run their own offices and dates, so use your county guide (linked below) for those.
Step 1: Check that your exemptions are on the bill
Exemptions lower the equalized assessed value (EAV) your tax rate is applied to. The Cook County Assessor's page says the Homeowner Exemption "saves a Cook County property owner an average of approximately $950 dollars each year."
The Cook County exemptions for homeowners, as listed on the Assessor's site:
| Exemption | Who it is for | Renews itself? |
|---|
| Homeowner | Owners who live in the property as their principal residence | Yes |
| Senior | Homeowners 65 or older (born in 1960 or prior) living in the property | Yes |
| Low-Income Senior Freeze | Seniors who meet the Senior Exemption rules with household income of $65,000 or less in calendar year 2024; it freezes the EAV, not the bill | No, apply every year |
| Persons with Disabilities | Owners who are disabled or became disabled during the 2025 tax year | Yes |
| Returning Veterans | Veterans returning from active duty in armed conflict | No, apply every year |
| Veterans with Disabilities | Veterans with a service-connected disability certified by the VA | No |
| Home Improvement | Owner-occupied class 2 homes that add value through improvements; up to $75,000 of added value exempted for up to four years | No application; the Assessor applies it after checking the building permit |
To see what your home actually gets, the Assessor says to open your Property Details and read the Exemption History and Status section.
If one is missing
Cook County's pages say the normal filing period has ended for tax year 2025 and that applications are now processed as Certificates of Error. The Assessor lists missing-exemption savings you can redeem for tax years 2025, 2024, 2023, 2022 and 2021. You can apply online or mail a paper form to 118 North Clark St., Room 320, Chicago, IL 60602. The Assessor notes that 2024 processing is slower than usual.
The Senior Freeze is the one people lose by accident, because it must be filed every year even though the Senior Exemption renews itself.
Outside Cook County, exemption applications go through your county's supervisor of assessments or assessor. Start with your county guide or the county's own website, and ask whether the Homeowner, Senior and Senior Freeze exemptions are showing on your record.
Step 2: Appeal the assessment
An exemption does nothing if the assessment underneath it is too high. Illinois assessment appeals start at the county level (the board of review, or in Cook County the Assessor and then the Board of Review), and each county sets its own township-by-township calendar. The Cook County Board of Review's site says it is currently accepting property assessment appeals and has a page of township dates and deadlines.
County guides with the filing rules and dates:
The strongest evidence, in the order most boards weigh it: a recent arm's-length sale of your own home, recent sales of similar homes nearby, and assessments of similar homes that are lower than yours. See what evidence wins a property tax appeal, and check your record for errors first: how to find and check your property record card.
Step 3: Take it to the state Property Tax Appeal Board
If the county board of review does not lower your assessment enough, Illinois has a second step, the Property Tax Appeal Board (PTAB). The clock there is short, so read the PTAB residential filing walkthrough the day your county decision arrives.
A worked example (made-up numbers)
These figures are invented to show the arithmetic. They are not Illinois rates or exemption amounts.
Say your home's EAV is $60,000, your combined tax rate is 7%, and your bill is $4,200.
- A missing exemption that would have taken $10,000 off EAV means the taxable EAV is $50,000, so the bill is $3,500. That is $700 a year back. If the exemption was missing for three tax years that Cook County still lets you redeem, the claim is about $2,100.
- A successful assessment appeal that lowers EAV from $60,000 to $54,000 cuts the bill by $420 at the same 7% rate ($6,000 x 0.07).
The two stack. Check the exemption first because it needs no comparables, then see whether the assessment supports an appeal.
What we could not confirm
We did not find a statewide table of current exemption dollar amounts on a page we could open, so we have not listed amounts. Cook County's pages give eligibility and dates; your county office gives the amounts for your county. Do not rely on an old article's dollar figures.
How Grove Hopper fits
We do not file or represent anyone. Our free check compares your assessed value against recent sales near you and shows your county's filing details. If you decide to appeal, our $50 Appeal Case prepares your comparable-property evidence and appeal documents. You review, sign and file everything yourself.
Frequently asked questions
What is the fastest way to lower an Illinois property tax bill?
Check that every exemption you qualify for is on your record. In Cook County the Assessor says missing exemptions can be redeemed through a Certificate of Error for tax years 2021 through 2025.
Do I have to reapply for the Homeowner Exemption every year in Cook County?
No. The Assessor's page says it renews automatically. The Senior Freeze and Returning Veterans exemptions do have to be filed every year.
Does the Senior Freeze freeze my whole tax bill?
No. The Cook County Assessor says it freezes the EAV only. Tax rates can still change, which changes the bill.
Does a home addition raise my taxes right away in Cook County?
Not necessarily. For owner-occupied class 2 homes the Home Improvement Exemption can exempt up to $75,000 of added value for up to four years, and it is applied after the Assessor checks the building permit. See also does a garage or addition increase property taxes.
Can I do this without a lawyer?
Yes. Exemption applications and county appeals are written for homeowners. See do you need a lawyer to appeal property taxes.
Check your number first
If you are not sure whether your assessment is out of line with similar homes, run the free check. It takes a couple of minutes, needs no account, and tells you straight when the numbers do not support an appeal.
