Cook County homeowners saw an average 16% increase on their second installment property tax bills in 2025. That’s not a gradual creep — it’s the kind of jump that changes household budgets overnight.
And some neighborhoods were hit far harder. West Garfield Park saw average increases of 133%. Across the South and West sides, double-digit increases were the norm, not the exception.
This wasn’t a fluke. It was the predictable result of a structural shift that’s been building for years — and it’s not going away in 2026.
Why your tax bill went up (even if your home didn’t change)
Property taxes in Cook County are a zero-sum system. The total amount collected stays roughly the same — it’s set by taxing bodies like school districts, municipalities, and park districts. What changes every year is who pays what share.
In 2025, commercial property values fell sharply, especially in Chicago’s Loop and along the Magnificent Mile. Office vacancy rates climbed as remote work continued. Hotels that never fully recovered from the pandemic saw further declines. Retail storefronts sat empty.
When commercial values drop, those properties pay a smaller share of the total tax levy. The difference doesn’t disappear — it gets redistributed to residential homeowners.
2026 isn’t going to be better
The same structural issues that drove the 2025 increase are still in play. Commercial property values downtown haven’t recovered. The tax burden is still tilted toward residential homeowners.
On top of that, the north and northwest suburbs face their triennial reassessment in 2026. That means homeowners in townships like Barrington, Elk Grove, Hanover, Maine, New Trier, Niles, Northfield, Palatine, Schaumburg, and Wheeling could see significant assessed value increases when new notices arrive.
First installment bills were due April 1, 2026. Second installment bills — the ones that reflect new assessments and the full tax rate — are coming later this year.
If you’re waiting to see what happens, you’re already behind.
The case for appealing: 273,907 homeowners can’t be wrong
In 2024, a record 273,907 Cook County homeowners filed property tax appeals. That number tells you two things: the system is accessible, and people are using it.
Homeowners who win their appeal commonly save $500–$1,500 per year. A successful appeal locks in savings across Cook County’s three-year triennial cycle, compounding the benefit of a single filing.
And here’s the part most homeowners don’t realize: in Cook County, when you file an appeal at the Assessor level, the Assessor does not raise your assessment — the outcome is either a reduction or no change. If you escalate beyond the Assessor to the Board of Review or the Illinois Property Tax Appeal Board, those bodies can adjust your assessment up or down, though increases are uncommon. For most homeowners who file at the Assessor level and stop there, the decision is between reduction and status quo.
The appeal process has two levels. You can file first with the Cook County Assessor’s Office during your township’s open window. If that doesn’t work, you can file again with the Board of Review later in the year. Two chances to get a reduction.
The entire process can be done online. No courtroom. No lawyer required.
What you need to file a strong appeal
The most effective appeals come down to one thing: comparable properties. You need to show that similar homes in your area — similar in size, age, bedrooms, bathrooms, and construction — are assessed at lower values than yours.
Three or more quality comps is the standard. The closer they are to your home in characteristics and location, the stronger your case.
This is the part that used to require hiring a tax attorney. Most charge 25–40% of your first year’s savings as their fee — every year, as long as the reduction holds. On $1,000 in annual savings, that’s $250–$400 per year going to the attorney — every year the reduction holds — instead of staying in your pocket.
How CheckMyTax helps — for a flat $99
We built CheckMyTax to give every homeowner the same quality of analysis that attorneys provide, without the ongoing percentage fee.
Here’s what you get for $99:
- 5 AI-matched comparable properties — selected using the same seven dimensions the county evaluates: square footage, bedrooms, bathrooms, year built, basement, construction quality, and geographic proximity
- Personalized cover letter — written specifically for your property and your comps, ready to submit with your appeal
- Step-by-step filing guide — exactly how to file with the Assessor’s Office or Board of Review, including deadlines for your township
- Emailed report — everything packaged and delivered to your inbox, ready to file
If we can’t find at least 3 strong comparable properties, you get a full refund. No exceptions.
You keep 100% of your savings. No percentage fees. No annual charges. One flat price for the data and analysis you need.
South District townships are open now
If you live in a south or southwest suburban township, your 2026 appeal window is open or opening soon. Townships in the south district include Bloom, Bremen, Calumet, Rich, Thornton, and Worth, among others.
Appeal windows are typically 30 days from when reassessment notices are mailed. Miss the deadline, and you’re locked into your assessed value until the next reassessment cycle — potentially three more years of overpaying.
The north and northwest suburbs will follow later in 2026 when their triennial reassessment notices go out.
Regardless of where you are in Cook County, the Board of Review offers a second appeal window later in the year. But the earlier you file, the more time you have to prepare and the better your chances.
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