Anyone who lives in Cook County has learned to fear the reassessment cycle. This is the triennial process that the Cook County Assessor’s Office (CCAO) uses to appraise all real property in the Chicago area. Cook County is divided into three sections, with one being examined every year. While property values and taxes can go up due to market forces, equalization, and tax rates, it is the reassessment that triggers large increases in tax bills.
In 2026, the southern and western suburbs of Chicago will be reassessed. This is the first time since the infamous 2023 reassessment that this region will suffer this fate. Needless to say, this puts many homeowners and businesses on edge, as the 2023 cycle was one of the most infamous in Cook County’s history. In this article, we will go over the historic case and what taxpayers can do to protect themselves in 2026.
The 2023 Reassessment
While Cook County and Illinois have historically been known for some of the steepest property taxes in the nation, the 2023 reassessment is one of the main incidents that has catapulted Chicago and the surrounding area into the state it is now. It was this reassessment that first saw some of the truly outlandish property tax increases. In many neighborhoods, increases of over 700% were seen, while others saw values raised across the board, seemingly without warning.
While some of the vast increases were thanks to post-pandemic market changes for both businesses and homes, other issues were also discovered. For instance, many basic mistakes were made, such as empty lots being assessed as new homes or businesses as residential property. This also led to the discovery that taxes were being placed on homeowners disproportionately instead of businesses. This was especially true of property tax appeals, which moved the burden to homes. In many ways, the 2023 reassessment foreshadowed things to come and started the current tax climate and issues that now plague Chicagoland.
The Error-Filled Year That Was 2025
Taxpayers in the southern and western suburbs do not have to look back a few years to see complications, as 2025 was characterized by them. Starting with a series of computer errors, assessments and tax bills across Cook County were delayed. With taxes coming out months later than they should have, many taxpayers were then ambushed by some of the largest tax increases in the history of Chicago. In particular, working-class Chicago neighborhoods on the South and West Sides were hit. The average tax bill in West Garfield Park, for instance, increased 133%. This does not include large individual spikes either. Even outside of the worst areas, the average tax bill increased by 16% for homeowners.
Cook County Taxes Have Increased 182% in the Past 30 Years
It is understandable if 2025 gives a taxpayer pause, as it was a culmination of decades of systemic issues that still exist. A recent study by the Cook County Treasurer showed that taxes have increased every year for over 30 years. This was due to loopholes in state laws, increasing pensions, tax incremental financing (TIFs), and increasing demands from taxing bodies, particularly schools. There has been no real effort to correct these problems, though there is finally some debate happening that will hopefully move things in that direction.
Communities Facing Reassessment
- Berwyn
- Bloom
- Calumet
- Cicero
- Lemont
- Lyons
- Oak Park
- Orland
- Palos
- Proviso
- Rich
- River Forest
- Riverside
- Stickney
- Thornton
- Worth
Appeals Can Protect Homes and Businesses
While laws at both the local and state levels are still up in the air, there are options for taxpayers who wish to lower their property values. Exemptions are the first option, and every one available to a taxpayer should be used. Once those are established, the next thing to look at is property tax appeals. These challenge the assessment of the CCAO and can significantly lower property values if used correctly. They can challenge based on factual errors like incorrect measurements or classification, which can cause major issues if left unchecked. They can also challenge values directly, either by protesting based on overassessment or on unequal assessment between properties.
The CCAO, the treasurer, and even the Cook County Clerk have all recommended that taxpayers protest as much as possible. While they cannot agree on who is at fault, they all recognize that only appeals by citizens can protect against rising values and taxes. While all of Illinois can appeal, Cook County has special rules that no one else has. This includes two separate dates to appeal, one to the CCAO and one to the Board of Review (BOR). These dates are separated by months, giving taxpayers a chance to go over their evidence. Filing appeals can be complicated, so we have a step-by-step guide to walk taxpayers through the process.
O’Connor Helps Taxpayers with Analysis and Evidence
One of the most important aspects of a successful appeal is the evidence. We at O’Connor offer professional services to enhance your appeal. We start by analyzing your assessment, looking for any issues. We can also send out a concierge team member to help look over your assessment, and they will also advise you on any exemptions you might be missing. Next, we will gather all of the evidence needed to back up your appeal, which includes gathering comparable assessment records and property sales dating back over the past three years. To achieve this, we use our patented databases, which can compare thousands of properties effortlessly.
You will be given a client success consultant who will walk you through everything and act as an dedicated point of contact. You will always have the same person working on your case, so you know that someone is dedicated to helping you. Once all the evidence has been gathered, we will coordinate an appeal with Kieta Law. They are experts in impressing the BOR and can help you in your journey to lower your values and taxes. Only a certified attorney can represent you before the BOR, so it is great to have a legal team on your side. You will only pay for our evidence and analysis if you and your attorney are able to lower your property taxes.
