Proviso Township property tax appeal, Cook County
The median residential assessment in Proviso Township rose 18.2% at its 2026 reassessment, and of the appeals decided for tax year 2025, 11.2% of 4,282 at the Assessor changed the value and 39.4% of 6,983 at the Board of Review ended in a decrease. Appeals for tax year 2026 close 27 Oct 2026 at the Cook County Assessor — verified 25 Sep 2026.
When Proviso Township can appeal
| Where you appeal | Opens | Closes | Date we verified it |
|---|---|---|---|
| Cook County Assessor | 14 Sep 2026 | 27 Oct 2026 | 25 Sep 2026 |
From the Assessor’s and Board of Review’s published 2026 calendars. Dates can change; confirm with the office before filing.
Proviso Township Board of Review and Assessor appeal results by year
| Tax year | Closed Assessor appeals | Share that changed the value | Board of Review appeals | Share decreased |
|---|---|---|---|---|
| 2023 | 10,315 | 22.9% | 11,514 | 47.4% |
| 2024 | 5,445 | 16.9% | 7,730 | 42.8% |
| 2025 | 4,282 | 11.2% | 6,983 | 39.4% |
Residential property classes (class 2, including condominium units). An Assessor appeal counts as changed when the Assessor’s record says the value changed; a Board of Review appeal counts as decreased when its result is “Decrease”. Shares aren’t printed from fewer than 30 appeals. Past outcomes don’t predict the result of any one appeal.
Proviso Township assessment increase, year on year
| Assessment year | Homes assessed in both years | Median change |
|---|---|---|
| 2024 | 47,650 | +0.0% |
| 2025 | 47,571 | +0.0% |
| 2026 | 47,532 | +18.2% |
Assessor mailed values for class 2 properties in Proviso Township, compared with the same property’s value the year before. Cook County reassesses one of its three regions (South for this township) each year; in other years the median change is usually 0%. The latest year can be partial while notices are still being mailed. 47,618 residential parcels are in the township today.
Proviso Township appeals: common questions
When is the Proviso Township appeal deadline?
For tax year 2026, the Cook County Assessor window for Proviso Township opened 14 Sep 2026 and closes 27 Oct 2026. We last verified that date against the office’s published calendar on 25 Sep 2026; dates move, so confirm with the office before you file.
What are the odds an appeal in Proviso Township works?
In tax year 2025, 11.2% of the 4,282 closed residential appeals the Assessor decided for Proviso Township changed the assessed value, and 39.4% of the 6,983 residential appeals the Board of Review decided ended in a decrease. Those are township-wide rates from closed cases, not a prediction for any one property.
Should I appeal to the Assessor or the Board of Review in Proviso Township?
They are separate filings and the table above shows both. For 2025, Proviso Township sent 4,282 residential appeals to the Assessor and 6,983 to the Board of Review; 11.2% and 39.4% of them respectively moved the value. The Board of Review hears appeals after the Assessor has closed a township, so missing the first window does not end the year.
How much did assessments go up in Proviso Township?
At the 2026 reassessment the median residential assessment rose 18.2%, measured across the 47,532 class-2 properties the Assessor valued in both 2025 and 2026. That is the middle of the township, not your property: half the homes moved more.
What if the Proviso Township window has already closed?
Nothing on this page files an appeal for you, and a closed window can’t be reopened here. The figures above are per tax year, so the same tables tell you what the next year’s filing looks like; the free assessment check compares your home with near-identical homes nearby whenever you run it.
Every answer here restates a figure printed elsewhere on this page. Nothing is added that we haven’t measured and sourced.
- Your own property: use the free assessment check, which compares your home with near-identical homes nearby.
- Tax bills, tax rates and exemptions.
- Commercial property and appeals filed with the Property Tax Appeal Board.
- Legal advice. CivicDelta doesn’t file appeals.
More: how a Cook County assessment appeal works · all 38 Cook County townships compared · everything we hold on property · how we compute these figures