Why Is Your Neighbor Paying Less Property Tax on the Same House?

It can be incredibly frustrating for homeowners in Cook County to discover that two nearly identical homes in the same neighborhood have very different property tax assessments. Even if the homes are the same size, age, and condition, one property may be assessed significantly higher than the other. This difference can mean hundreds or even thousands of dollars more in property taxes each year for the homeowner with the higher assessment.

If you've ever compared your tax bill with a neighbor's and wondered why you're paying more, you're not alone. Understanding why these discrepancies happen is important. The Cook County Assessor's Office uses specific methods to value properties, but sometimes assessments don't reflect a home's true market value. Knowing the reasons behind these differences can help you protect your investment and make sure your taxes are fair.

This blog explains why similar homes can receive different assessments and how a Cook County Property Tax Attorney can help you level the playing field.

What Causes Assessment Differences Between Similar Homes

Several factors can lead to discrepancies between assessments of homes that look almost identical:

Timing of Sales and Market Changes

Cook County reassesses properties on a three-year cycle, with different townships reassessed each year. Your assessment is based on recent sales of comparable properties in your area. If one home sold during a market peak and another sold during a slower period, the Assessor may use different data to value them. Even though the homes are the same, the timing of when comparable sales occurred can create big differences.

Small Property Mischaracterizations That Add Up

Even neighboring properties that appear nearly identical can be assessed very differently due to how they are classified or recorded by the Assessor. In some cases, properties may even fall into different class designations based on small technical differences—such as a variance of as little as 10 square feet in recorded living area.

Other common mischaracterizations can also affect assessed value. For example, a home recorded as masonry construction may be assessed higher than a nearly identical neighboring home recorded as frame or siding, even when the real-world difference is minimal. These classification and data-entry differences—rather than true market value—can drive significant assessment disparities.

When these details are inaccurate or overstated, they can result in a higher assessed value and increased property taxes. Identifying and correcting these issues can make a meaningful difference in your tax burden.

Exemptions Make a Big Difference

Property tax exemptions can create substantial differences in what you actually pay, even if two homes have the same assessed value. Common exemptions in Cook County include the Homeowner Exemption (saves approximately $950 per year), Senior Citizen Exemption ($8,000 reduction in equalized assessed value), Senior Freeze Exemption, and Disabled Persons Exemption ($2,000 equalized assessed value reduction). If one homeowner applied for these exemptions while the neighbor didn't, their tax bills will be very different.

Previous Appeals Changed the Assessment

If one homeowner successfully appealed their assessment in the past while the neighbor never filed an appeal, their assessed values may now be different. A successful appeal can lower your assessment for that reassessment cycle. This means two identical homes can have different assessments simply because one owner took action to challenge an overvaluation.

Errors in the Assessor's Records

Mistakes in property records are more common than many homeowners realize. Common errors include incorrect square footage, wrong number of bedrooms or bathrooms, listing improvements that don't exist, misclassified property type, or wrong lot size. Even a small clerical error can significantly increase your assessed value compared to an identical home with correct information.

Location Differences Based on Assessor Neighborhoods

Even homes located directly across the street from one another may be placed in different official Assessor neighborhoods. When this happens, the Assessor may rely on entirely different comparable sales to value each property, even though the homes are physically close and appear similar.

Because assessments are often driven by neighborhood-specific data, being assigned to a different Assessor neighborhood can result in a significantly different valuation. These boundary distinctions are not always obvious to property owners, but they can meaningfully impact how a property is assessed and taxed.

Why Fair Assessments Matter for Your Wallet

Assessment discrepancies can result in one homeowner paying substantially more in property taxes than their neighbor for essentially the same home. Over a decade of homeownership, even a $500 annual difference adds up to $5,000 in overpayments.

High assessments don't just affect your annual tax bill. They can also create problems when you're trying to refinance or sell. Buyers compare property taxes when making offers, and a home with unusually high taxes compared to similar properties nearby can be harder to sell or may require a lower sale price.

Get Legal Guidance

A property tax attorney can help you navigate the appeal process and present the strongest possible case. Professional help can review your assessment, research comparable properties, ensure your documentation is complete, file your appeal correctly and by the deadline, represent you at hearings, and handle all communications with the Assessor's Office. This significantly improves your chances of success and ensures you don't miss important deadlines.

Stop Overpaying While Your Neighbor Pays Less

Assessment discrepancies happen due to timing, property differences, exemptions, previous appeals, errors, and location factors. But just because these differences exist doesn't mean you have to accept an unfair assessment.

Aaron Fox Law assists Cook County homeowners in reviewing assessments, gathering evidence, and filing successful appeals. 

To learn more or schedule a free consultation, visit Aaron Fox Law's property tax page for details on how to get fair assessments throughout Cook County.

Don't keep overpaying while your neighbor enjoys lower taxes on the same home. Take action to ensure your assessment is fair and accurate.