Your property tax bill depends on two things: your property's assessed value and the tax rates set by your local taxing districts. An appeal can't change the rates, but it can lower your assessment if it's higher than your property is worth or if the county has your home's details wrong. In Cook County, filing an appeal is free, and homeowners can file on their own.

Start with your exemptions

Before appealing, make sure you're receiving every exemption you qualify for. The homeowner exemption doesn't carry over from a prior owner; new owners must apply. Other exemptions cover seniors, the senior assessment freeze, people with disabilities, veterans and longtime homeowners. If an exemption was missed in a past year, the Assessor can correct it through a certificate of error. You can see what's on your property at Cook County Property Info.

Level 1: The Cook County Assessor

When: each township opens for appeals on its own schedule. You typically have about 30 days after your township's reassessment notices are mailed, and the last day to file is printed on your notice and on the Assessor's appeal calendar.
How: file online through the Assessor's website. There's no fee and you don't need to hire anyone.
Grounds: the property characteristics are wrong (square footage, bedrooms, basement, lot size), the estimated market value is more than the home would sell for, or the assessment is out of line with similar homes nearby.

Level 2: The Board of Review

Whether or not you appealed to the Assessor, you can appeal to the Cook County Board of Review when your township opens there, usually for about 30 days. The Board of Review is a separate, independent office, and you can request a hearing. It offers free seminars and online filing.

Level 3: The Property Tax Appeal Board or the courts

After the Board of Review decides, you can appeal to the state Property Tax Appeal Board (PTAB) within 30 days of the postmark date of the Board of Review's written decision. PTAB charges no filing fee, and individuals may represent themselves; corporations, LLCs and partnerships must be represented by an Illinois attorney. Another option is a tax objection case in the Circuit Court of Cook County, which follows different rules and deadlines. An attorney can help you decide which path fits.

Evidence that helps

A recent purchase: your closing statement if you bought the home within the last few years at an arm's-length sale.
An appraisal close to the assessment date.
Comparable properties: similar homes nearby with lower assessments, or recent sales of similar homes at lower prices.
Corrections: photos, a survey or plans showing the county's description of your home is wrong.
Condition or vacancy: documentation of serious damage or vacancy during the tax year.

Things to know

A lower assessment doesn't always mean a lower bill, because tax rates and exemptions also change.
Be cautious with unsolicited mail from appeal companies; filing is free, so compare any fee against what you might save.
If you're buying or selling, the tax bill and any pending appeal affect the proration at closing. Ask your attorney how an appeal filed by the seller is handled in your contract.
Rental and investment owners should keep income and expense records; they're often requested for non-owner-occupied property.

Official links

Questions about how property taxes affect your purchase, sale or estate? Schedule a consultation.

General information about Cook County property tax appeals, reviewed October 2026. Filing dates, rules and forms change each year; always confirm with the Assessor, Board of Review or PTAB.

People. Property. Possibilities. · Schedule a consultation: (312) 809-9766 or 24-hour scheduling (872) 326-9600 · sharakamal.com

By Attorney Shara Kamal. General information for Chicago-area readers; not legal advice for a specific situation.