If you're buying in Chicago, the property tax number in the listing is not your property tax number. That distinction has always been true in Cook County. In 2025 and 2026, it matters more than it ever has.

Here is what happened. The Cook County Assessor's Office completed a citywide reassessment of Chicago's residential properties in 2024. The results, which hit tax bills in 2025, were significant: the median residential property tax bill in Chicago jumped 16.7% — the largest single-year increase in Illinois history. For some neighborhoods, the numbers were far more severe. In West Garfield Park, the median homeowner's bill more than doubled, rising from $1,482 to $3,448. In nine predominantly Black Chicago community areas, median residential bills jumped by more than 50%.