Both counties start with the same first step: the Senior Citizens Homestead Exemption. In DuPage, it takes a maximum of $8,000 off your home's equalized assessed value (EAV) if you are 65 by December 31 of the assessment year, own and occupy the home, and are liable for its taxes — and once you're enrolled, most taxpayers need to do nothing further to keep it. Cook County's version also reduces EAV by $8,000 (you must have owned and occupied the home as of January 1 and be 65 during the tax year), and the Cook County Assessor now automatically renews it for homes that haven't been sold.
Lower income? Add the Senior Freeze. The Low-Income Senior Citizens Assessment Freeze locks your home's taxable assessed value at a base-year level, so rising property values stop pushing your bill up. (It freezes the assessed value — not the tax bill or the tax rate, so a rate increase can still raise your bill.) For the 2026 application, the household income limit is $75,000 in both counties. In DuPage you must first have the Senior Homestead Exemption, and the filing deadline is October 1 each year (Supervisor of Assessments, 630-407-5858). In Cook County the freeze must be re-applied for every year, because income can change.
Still squeezed? The state will lend you the tax money. The Senior Citizen Real Estate Tax Deferral Program works like a loan: the State of Illinois pays up to $7,500 a year of your property taxes, charges 3% interest per year, and is repaid when the home is sold or transferred, or within a year after the owner's death. As published for the current cycle you must be 65 by June 1, have household income of $75,000 or less, have owned and occupied the home at least three years, carry fire/casualty insurance, and owe no back taxes. DuPage residents apply through the County Treasurer between January 1 and February 27 (630-407-5900); Cook County residents apply through the Cook County Treasurer's annual window.
Details: DuPage Supervisor of Assessments — senior exemptions · Cook County Treasurer — senior exemptions