Tax appeals · Updated July 2026
The 2026 Cook County reassessment: what south and west suburban owners should do
Cook County reassesses one-third of the county every year on a rotating cycle — and in 2026 it’s the south and west suburbs’ turn. Over the year, township by township, homeowners receive reassessment notices proposing the value that will drive the next three years of tax bills.
That makes this the highest-stakes assessment year these townships will see until 2029 — in the part of the county where effective tax rates run highest. A value you don’t challenge now compounds across three bills. Here’s how the cycle works and how Cook’s unusually homeowner-friendly appeal structure lets you challenge it twice.
How the triennial works
Cook County divides into three assessment districts — the City of Chicago, the north suburbs, and the south/west suburbs — each reassessed every three years. When your township’s notices publish, a roughly 30-day window opens to appeal with the Assessor’s Office. The windows roll through the year, township by township, so your neighbor two towns over may be on a different clock.
Your reassessment notice shows the proposed assessed value (residential property is assessed at 10% of market value, before the state equalization factor). The number to interrogate is the market value the assessment implies — is it what your home would actually have sold for?
Why the south and west suburbs have the most at stake
Effective tax rates in the south and west suburbs are among the highest in the nation — commonly two to three times the City of Chicago’s, and in some communities far beyond that. The same over-assessment costs a south-suburban owner multiples of what it would cost elsewhere.
Appeal participation has historically been lowest in exactly these townships — north-suburban owners appeal at several times the rate of south-suburban owners. That gap is money left on the table, and it means the boards are used to seeing far fewer challenges from these communities than the housing stock justifies.
The two-bite appeal: Assessor, then Board of Review
Cook County gives homeowners two independent shots in the same year. First, appeal to the Assessor’s Office during your township’s reassessment window. Whatever happens there, you can appeal again to the Board of Review — a separate, elected body — when its own township window opens later in the year. Many owners file both; roughly half of Board of Review appeals win some reduction.
Both venues act on the same fuel: evidence that the implied market value is too high. Comparable-sales analysis — documented, adjusted, and signed by a licensed appraiser — is the strongest form of that evidence, and it works at both stops without redoing anything.
- Watch for your township’s reassessment notice (windows roll all year)
- Bite one: Assessor’s Office appeal, ~30 days from notice publication
- Bite two: Board of Review appeal when your township’s BOR window opens
- One licensed appraisal serves both venues — and the next two years
What to do when your notice arrives
First, translate the assessment to its market-value claim and check it against reality — recent sales of similar homes in your area, and any facts the mass model can’t see (condition problems, functional quirks, a record-card error on square footage or bathrooms). Reassessment years are when record-card errors get locked in, so check the card even if the value looks plausible.
If the numbers look wrong, move inside your window: the ~30-day clocks are strict, but because the Board of Review provides the second bite, missing the Assessor window doesn’t end your year. Given three years of bills ride on this value, the math on professional evidence is at its best in a reassessment year.
Questions people ask
The south and west suburban assessment district — the Assessor publishes each township’s notice dates and appeal windows on its annual calendar as the year progresses. Your reassessment notice is the definitive signal.
Yes. Every township gets an appeal window with the Assessor and the Board of Review every year — reassessment years just carry the most at stake, because the new value anchors the next three.
Not for residential appeals — homeowners file directly with the Assessor and Board of Review online. Attorneys are common for commercial property; for a home, the evidence matters more than the representation.
We’re not an AVM, a computer model, or a real-estate agent estimate. Every report is prepared under the Uniform Standards of Professional Appraisal Practice (USPAP) and signed by a licensed appraiser in your state — the same qualification required for mortgage appraisals.