How Condos are Reassessed

The job of the Assessor’s Office is to calculate a fair market value for your property. The market value is how much your property could sell for based on the current real estate market. For residential properties, including condos, your property’s assessed value equals 10% of its fair market value, per Cook County ordinance.  

How the Assessor estimates what my condo is worth  
For the most part, condos are valued the same way as detached homes: the Assessor’s Office uses a statistical model to estimate the value of both sold and unsold properties.  

However, condos differ from detached homes in an important way: condos are part of one building. Each condo unit is assigned a percentage of ownership, i.e. a fractional share of the building’s total value. For example, in a ten-unit building one unit could be assigned 25% of ownership, another 15%, and the remaining six units are each assigned 10%.  

Image of condominium property

The percentage of ownership is not determined by the Assessor’s Office. Rather, it is determined when the unit is built and the developer of the building usually files a Condominium Declaration with the County.  

The Assessor’s Office first uses a statistical model to determine the total value of the building. Then, the Office applies each condo unit’s percentage of ownership to the building value to determine each unit’s value. 

What affects the Fair Market Value of a condo

Condo values are typically driven by:

  • Location, such as city, neighborhood, and school district
  • Characteristics of the condo building, such as age and the total number of units
  • Characteristics of the condo, such as its percentage of ownership relative to other units in the building 
How does the Assessor's Office determine a condo's value? 

The Assessor's Office estimates the total value of the condo building by creating a statistical model using sales of units in the building and nearby, similar buildings. Then, our team calculates the market value for each unit, aligning with the unit's percentage of ownership which is listed in your Condominium Declaration.

Click here to view a more detailed explanation and the modeling pipeline for condos on GitHub, a platform that hosts our open-source valuation code. 

How do I obtain my Condominium Declaration? 

A Condominium Declaration is a fundamental document that establishes the existence of - and further governs the use and maintenance of - a condominium property. The percentage of ownership is created when a Condominium Declaration is filed with the County (usually by the developer of the building). Each owner should have a copy. Contact your HOA if you need a copy of this document. This document includes your unit's percentage of ownership.

You can also find your condo’s percentage of ownership by going to its property’s PIN detail page, scrolling down to the blue “Access more in-depth property details” button, and viewing the “Common Interest” percentage.  

My unit is similar to my neighbors, why is my assessed value higher?

Assessed values depend on the unit’s percentage of ownership, which can differ for each unit. A unit with a higher percentage of ownership will have a higher value than other units in the same building with lower percentages of ownership.  

To compare condo assessments within a building, it is important to compare your unit with units that have a comparable percentage of ownership.  

You can find your condo’s percentage of ownership by going to its property’s PIN detail page, scrolling down to the blue “Access more in-depth property details” button, and viewing the “Common Interest” percentage.  

Or, to download data about many condo units, the Assessor’s Office publishes its database of condo unit characteristics on Open Data.  

Can I file an appeal on my own or should my condo building file together?

Condo owners can file an appeal on their own or as a group. If appeals are filed as a group, then results will include all of the units. If an owner files individually, then they will only receive the appeal results pertaining to their unit.

If anyone files in your building, our office reviews the values of the rest of the building units as well. So you may get an updated assessment notice even if you or the building as a whole does not file an appeal. 

Do I need to hire a lawyer to file an appeal?

No. You are NOT required to hire a lawyer to file an appeal. We try to make the process as simple as possible so that owners can do it on their own. 

Can an HOA file an appeal for the entire building?

Many HOAs file on behalf of all owners in a building. This is dependent on your HOA. An owner can file as a group or individually. 

Do I have to file an appeal?

Owners do not have to file an appeal. If the HOA files for the entire building, contact your HOA to opt-out.