Proviso Township's 2026 reassessment notices are out, and the Assessor's appeal window runs from September 14 to October 27, 2026. Across 47,544 homes, the median assessment rose 19.0% from the final 2025 value, and 89.0% of homes went up. Unlike most of the south and west suburbs, about one home in 13 went down. Proviso covers Bellwood, Berkeley, Broadview, Forest Park, Hillside, Maywood, Melrose Park, Northlake, Stone Park and Westchester, with parts of Brookfield, La Grange Park and North Riverside.
The numbers
| Proviso Township, residential | |
|---|---|
| Homes reassessed | 47,544 |
| Median change, 2025 final to 2026 notice | +19.0% |
| Total assessed value change | +20.2% |
| Homes that went up | 89.0% |
| Median 2026 assessed value | $28,000 (about $280,000 market value) |
| Median 2025 composite tax rate | 12.18% of equalized value (ranges 5.8% to 17.9% by tax code) |
| Assessor appeal window | September 14 – October 27, 2026 |
| Board of Review window | not yet published; typically opens after the Assessor certifies the township |
Residential (Class 2) parcels only. "2025" is each home's final Board of Review value for 2025; "2026" is the value on this year's reassessment notice. Source: Cook County Assessor assessment files as loaded in September 2026.
What 19% means on a Proviso bill
Take the median home: $28,000 assessed, times the 3.03 state equalizer, is $84,840 of equalized value. At Proviso's median 2025 rate of 12.18% that is about $10,340 of gross tax, less about $1,220 for the Homeowner Exemption, so roughly $9,120. A 19% higher assessment does not become a 19% higher bill, because the rate is recomputed when the levies are divided by the new, larger township base. What moves your bill is how your increase compares with your neighbors'. A home that rose 29% in a township that rose 19% will pay a bigger share of the same levy.
What Proviso appeals did last year
County-published outcomes for all residential appeals in Proviso Township for tax year 2025, every appellant, represented or not:
| Venue | Appeals decided | Received a reduction | Average cut (of assessed value, winners) |
|---|---|---|---|
| Assessor | 4,282 | 480 (11.2%) | 8.7% |
| Board of Review | 6,983 | 2,754 (39.4%) | 8.5% |
Two things to read from that. The Board of Review reduced 3.5 times the share of appeals that the Assessor did, so the Assessor window is the first attempt, not the only one. And a 9% cut on the median home is about $2,520 of assessed value, which at Proviso's rate is roughly $930 a year, for three years until the next reassessment.
How to appeal your Proviso assessment before October 27
- Check the property characteristics on your notice against the house. Square footage, number of bathrooms, basement, garage and exterior type all feed the model.
- Compare against similar homes. The strongest residential argument in Cook County is lack of uniformity: your assessed value per square foot is higher than comparable homes in your neighborhood code. Our free property check pulls the comparables from the county's own data and shows the gap.
- File online with the Assessor by October 27, attaching the comparables. If the Assessor does not reduce it, file again at the Board of Review when Proviso's window opens; the two are independent.
- Do not confuse exemptions with appeals. A missing Homeowner ($10,000 of equalized value) or Senior ($8,000) exemption is fixed with a Certificate of Error, not an appeal; your second-installment bill is where you check it.
Commercial and apartment buildings
Commercial and industrial (Class 5) assessments in Proviso rose a median 20.7% across 3,276 properties, and apartment buildings of seven units or more (Class 3) a median 24.0% across 506. Those are valued on income, so the appeal is built on the building's rent roll and expenses; see the Proviso commercial appeal guide.
We file appeals for owners in Proviso from our office in Palos Heights. Our fee is 25% of the first year's savings, nothing if there is no reduction. Enter your address to see where your home sits against the ones around it, read the Proviso residential appeal guide, or see every township's current dates.
