Why did my assessed value increase?

Your assessed value may increase in Cook County when the Assessor determines that your property’s market value has increased or when property records are updated.

An increase in assessed value does not always mean your property taxes will increase, but it can affect how your tax bill is calculated.

Several factors can cause an assessment increase.

Common Reasons Your Assessed Value May Increase

1. Market Value Changes

One of the most common reasons is rising property values in your area.

If homes or commercial buildings near your property have sold for higher prices, the Assessor may adjust your property’s estimated market value to reflect current market conditions.

2. Countywide Reassessments

Cook County follows a three-year reassessment cycle.

During reassessment years, the Assessor reviews property values across entire areas, including:

• The City of Chicago

• North suburban townships

• South and west suburban townships

If your township is in its reassessment year, many properties may see changes in their assessed values.

3. Property Improvements or Renovations

Your assessment may increase if improvements were made to the property, such as:

• Home additions

• Major renovations

• New structures or buildings

• Finished basements or upgraded features

These improvements can increase the property’s estimated market value.

4. Updated Property Records

Sometimes the Assessor updates property records after discovering missing or incorrect information.

Examples include:

• Updated square footage

• Additional structures

• Corrected building details

If the updated data shows the property is larger or more valuable than previously recorded, the assessed value may increase.

5. Commercial Property Income Changes

For commercial properties, assessments may increase if:

• Rental income rises

• Vacancy rates decrease

• The property becomes more profitable

Income-producing properties are often valued partly based on financial performance.

Does a Higher Assessed Value Always Mean Higher Taxes?

Not always.

Your property tax bill depends on multiple factors, including:

• Your property’s assessed value

• The local tax rate set by taxing districts

• The equalization factor applied by the state

Because of these variables, a higher assessed value does not automatically mean your tax bill will increase.

What If You Believe the Increase Is Incorrect?

If you believe your property was overassessed, you may file a property tax appeal when your township’s filing window opens.

An appeal allows you to present evidence such as:

• Comparable property sales

• Property condition issues

• Income and expense data for commercial properties

This evidence may support a request to reduce the assessed value.

Key Takeaways

• Assessed values may increase due to market changes or reassessment cycles.

• Property improvements or updated records can also raise assessments.

• Commercial property income changes may affect valuations.

• Higher assessments do not always mean higher taxes.

• Property owners may file an appeal if they believe the assessment is too high.

Understanding why assessments change helps Cook County homeowners and commercial property owners evaluate whether their property value appears accurate or may require a review through the appeal process.