Two months after Cook County released reassessment figures showing a 25% median increase for Oak Park Township, property owners are facing a new reality: those higher assessed values will appear on second-installment tax bills in the summer of 2027.

Cook County Assessor Fritz Kaegi released the initial 2026 assessments on May 6. Oak Park Township Assessor Ali ElSaffar said the median increase broke down to about 24% for single-family homes, 25% for condos, 11% for townhomes, 28% for apartment buildings, and 21% for commercial properties.

The Assessor's Office set the 2026 median estimated market value for a single-family home in Oak Park Township at $559,000. Condos came in at $204,000. Small apartment buildings were pegged at $594,000. In Cook County, residential properties carry a 10% level of assessment, meaning a home valued at $559,000 has an assessed value of $55,900.

The median sale price of an Oak Park home rose from $513,000 at the 2023 reassessment to $595,000 at the 2026 reassessment, a jump of roughly $82,000 in three years, according to ElSaffar. The Cook County Assessor's Office reassesses the south and west suburbs every three years; the last cycle was 2023.

"What we always have to educate most people about … is that most people think that the property tax is like the sales tax or the income tax. It doesn't work that way," ElSaffar told the Wednesday Journal in May. "A lot of people think … 'if my assessed value has gone up by 25% therefore my taxes are going to go up by 25%.' People get very nervous about that, understandably so, if that were actually the case, but it's not."

Oak Park property owners collectively paid $264 million in property taxes last year. After the 2023 reassessment, about one-third of homeowners saw tax reductions while roughly 40% experienced double-digit increases, according to ElSaffar.

Homeowners who received reassessment notices on May 6 had until June 18 to file an appeal with the Cook County Assessor's Office. That window has closed. Property owners who filed appeals may still pursue the matter through the Cook County Board of Review. The Wednesday Journal published the Cook County Clerk's full list of April 2026 property transfers for Oak Park and River Forest on July 16; those transactions will feed into the next reassessment cycle, likely in 2029.

The 2026 assessed values will be reflected on tax bills issued in the summer of 2027.