While the northern parts of Cook County were ravaged by reassessment in 2025, the Cook County Assessor’s Office (CCAO) and the Cook County Treasurer’s Office experienced their own problems. In an effort to streamline the arcane property tax process in Cook County, there have been measures throughout the past decade to join computer systems between the two governmental agencies. Unfortunately for the agencies and taxpayers, there have been several computer errors since May that have caused a litany of problems across the county.

While this story is still ongoing, we will explore why this is happening and what consequences have occurred and will keep occurring to the people of Cook County. Currently, home values are being passed out across the county and the window to protest property values is open in some townships while shutting in other ones. While this is happening, taxpayers can expect their tax bills to be delayed. Initially set to be due on August 1, 2025, it appears that things will be backed up for some time.

The Root Cause of the Issue

Like many things involving the CCAO, this has origins in good intentions that went pear-shaped. In order for the complex property tax system to work, the CCAO, the Treasurer, and the County Clerk must all work together to assess property, collect taxes, and figure out where to spend the money. In addition, the Board of Review (BOR) must certify these results and is also responsible for ruling on property tax appeals. It was decided to upgrade the decaying computer infrastructure that ties the records of the four organizations together. This should have allowed faster gathering and sharing of information, making it a seamless process that benefits both the government and taxpayers.

Unfortunately, there have been plenty of delays in the process. The contractor that has been working on the system for almost a decade has experienced many setbacks. This seems to have thrown the proverbial monkey wrench into the entire process. However, it is not clear exactly why this is happening. Local journalists and the government agencies themselves are trying to uncover just what is happening and who is to blame.

The Blame Game

CCAO is blaming the contractor, Tyler Technologies, for the delays. Tyler has allegedly missed several deadlines throughout the process. However, other government agencies are blaming CCAO for the delay, as they believe that the assessor has not done enough work to compile accurate assessments, which then delays everything further down the line. It has also been asserted that the CCAO should have kept the old infrastructure in place while the upgrade was going on, rather than blowing up the whole thing with a new system. There have also been many spats between the CCAO and the BOR, as the BOR has pointed out the record number of errors they are seeing in the tax appeals they are reviewing. In response, the CCAO has generally been belligerent to the BOR and even blamed them for higher property taxes and values.

Passing the buck is a longstanding tradition in Cook County government and finding out who is directly responsible has proven to be a bear. Just as Cook County’s ridiculous property taxes have many responsible parties, there seems to be enough guilt to go around. No matter who is ultimately responsible, these problems are causing several knock-on issues for property owners, taxpayers, and government entities.

The First Issue

In 2021, the first problem reared its head. Thanks to problems converting over databases, CCAO was late in preparing assessed values. Because agencies up the chain need this information to create tax bills and budgets, this bottleneck caused delays across the board. And this data was not just late, but highly inaccurate. This is where the horror stories about triennial reassessment truly began. Vacant lots were given the same property values as mansions, homeowners ended up getting the tax burdens for businesses, and some values handed out were mind-blowing for homeowners and business owners alike. Key bits of information were also missing in important areas.

If this were fiction, we would certainly classify this incident as foreshadowing, as it correctly forecasted the current problems. Much like today, this also quickly turned into a circus of in-fighting, where every party blamed the other. It also led to issues with property tax appeals, as the BOR and the appeal timeframe needed to be readjusted. With the whole system backed up, some government entities were forced to take out loans on future revenue, which added future interest payments into the mix. The shadow of this incident looms large even today.

May 2025

The 2025 tax season got off to an inauspicious start in May. The CCAO announced that tax bills would be delayed due to several data errors. The Cook County assessor once again blamed Tyler Technologies for the delay, claiming that they had been blaring the alarm for almost a year about the issues. However, other government entities claimed that it was the CCAO to blame once again, and that they had not finished their assessments quickly enough, making the computer system a convenient scapegoat.

The delay not only caused bills to come out months later than they should have, but like in 2021, it had several downstream effects. One of the largest was that the equalization factor had to be delayed as data needed to be tabulated to formulate it. The equalization factor has an outsized impact on Cook County, as the county’s valuation rate of 10% must be adjusted to meet the state’s requirement of 33.33%. This crucial step being in limbo was the main reason it took so long for the first statements to be released.

The Current Mix-up

This brings us to July in Cook County. Once again, the poisoned tree is bearing fruit. Thanks to the previous delays and some new problems, there are now several issues to address. First, refund payments to taxpayers that won property tax appeals or settlements with the Property Tax Appeal Board (PTAB) cannot be processed. Currently, the Cook County Treasurer is unable to send out checks to taxpayers that total over $56 million. This is not only a lot of money to be holding, but each check represents relief for some of the most over-taxed people on the planet, ones that took time and effort to get their taxes corrected in the first place. Currently, this is affecting around 25,000 taxpayers and will continue to do so until Certificates of Error can be honored.

This second issue is that the computer problems are keeping over $216 million from being distributed across Cook County. As the primary way to pay for infrastructure and government services, property taxes are the lifeblood of Chicago. It is estimated that this is causing a budget shortfall for over 2,200 taxing bodies. Like the issues that popped up in 2021, this could force the bodies to take on loans on the taxes to fill in the gap until the money can be issued. In the meantime, these important government offices and services will have to figure out how to keep things working.

At the heart of this is yet more computer errors and more bickering between CCAO, the Treasurer, the County Clerk, and Tyler Technologies. It seems that all parties involved are more focused on passing around blame than they are on fixing the situation. This problem was only discovered on July 10 and shows no signs of being solved any time soon. This is a continuation of the problems from May in many ways, showing that they were never addressed.

What’s Next?

While the amount of finger pointing is becoming comical, there is not much concrete evidence of what’s going to happen next. Once the computer problem is solved, refund checks will be released and funding to government institutions is supposed to start once again. As this is still in the early stages, the solution is not yet known. One would hope that this would lead to unity between both the contractor and the Cook County government, but this has been going on for years. It is also expected that tax bills will be delayed by at least a month, with September being the new target date.

Implications for Taxpayers

With the aggressive reassessment of the northern areas, the failure of sensible property tax reform in the legislation, and the series of computer errors sabotaging the system, it should be hammered into the minds of taxpayers across Cook County that they must protest their taxes and values. While this may be delayed, as we have seen with this series of checks, it has never been more important to be sure you’re paying the correct taxes on the correct values. These computer errors are not just administrative but have routinely been found to be negatively influencing assessments. This is probably how a vacant lot got recorded as a mansion or a family home got stuck with a tax bill 700% higher than the year before.

Even the Cook County government is suggesting that taxpayers appeal every year, as they know the state of their own system. Taxes and values are only going up and protests remain the only remedy that homeowners and businesspeople can count on to pay their fair share. In some townships, informal appeals are still available to be filed, while others are going through the BOR process, or are about to.

Now is the best time to join O’Connor. We will protest your taxes, as recommended, and make sure that you never miss a deadline. While we cannot stop computer errors, our appeals can help mitigate the damage. Without a protest, you are simply forced to pay the whole amount. With an office in Aurora, we know both Cook County and the collar counties well. Reach out today and let us help you protect your home or business.

About O’Connor:

O’Connor is one of the largest property tax consulting firms, representing 185,000 clients in 49 states and Canada, handling about 295,000 protests in 2024, with residential property tax reduction services in New York, Texas, Illinois, and Georgia. O’Connor’s possesses the resources and market expertise in the areas of property tax, cost segregation, commercial and residential real estate appraisals. The firm was founded in 1974 and employs a team of 1,000 worldwide. O’Connor’s core focus is enriching the lives of property owners through cost effective tax reduction.

Property owners interested in assistance appealing their assessment can enroll in O’Connor’s Property Tax Protection Program ™. There is no upfront fee, or any fee unless we reduce your property taxes, and easy online enrollment only takes 2 to 3 minutes.