Property Tax Appeal FAQ: Every Question Chicago Homeowners Ask Us

Cook County property taxes are among the most complex in the country, and we hear questions about them constantly — from buyers wondering what they are walking into, from homeowners who just received a Notice of Proposed Assessment, and from long-time owners who have never looked closely at whether their assessment is accurate. This FAQ compiles every significant question we have been asked over the years, organized by topic, with complete answers. Consider it a reference document you can return to at any point in the process.

The Basics: Assessments and How They Work

What is a property tax assessment?

An assessment is the Cook County Assessor's estimate of your property's market value, expressed as a fraction of that value — specifically 10% for residential properties under Illinois law. If the Assessor estimates your home is worth $400,000, your Assessed Value (AV) is $40,000. This AV is then processed through the equalization factor and tax rate to produce your actual tax bill.

What is an Equalized Assessed Value (EAV)?

EAV is your Assessed Value multiplied by the State Equalization Factor (also called the multiplier). Illinois law requires that assessed values statewide be equalized to one-third of market value. The Illinois Department of Revenue calculates a multiplier each year for Cook County to achieve that target. The multiplier has historically been approximately 2.9 to 3.0. So if your AV is $40,000 and the multiplier is 2.9, your EAV is $116,000. Exemptions are subtracted from EAV; the tax rate is applied to the net EAV after exemptions.

What is the State Equalization Factor?

The equalization factor (sometimes called the "multiplier") is a number calculated annually by the Illinois Department of Revenue to bring Cook County's overall assessment level into compliance with the statutory one-third of market value requirement. It is applied uniformly to all properties in Cook County. Individual homeowners cannot appeal the equalization factor — it is a countywide adjustment. You can only appeal your assessed value.

How is my tax bill calculated from my assessment?

The formula is: (AV × equalization factor) − exemptions = net EAV. Net EAV × tax rate = annual tax bill. The tax rate is set by your taxing bodies (school district, city, county, park district, etc.) and varies by location. In Chicago, composite rates typically range from 6% to 9%. The rate is set each year based on the total levy amount divided by all the net EAV in the taxing district.

What is a Property Index Number (PIN)?

A PIN is the unique 14-digit identification number assigned to every parcel of property in Cook County. It is how the Assessor, Treasurer, and Board of Review identify your property in their systems. You need your PIN to look up your assessment, check your exemptions, pay your taxes, and file an appeal. Your PIN appears on your tax bill, your Notice of Proposed Assessment, and can be found by address at cookcountytreasurer.com or cookcountyassessor.com.

What is a property record card?

The property record card is the Assessor's file on your property. It contains the physical characteristics used in the assessment model: square footage, number of bedrooms and bathrooms, lot size, construction type, year built, basement and garage details, quality rating, and any improvements. Errors in the property record card are a legitimate basis for appeal. You can view yours at cookcountyassessor.com by entering your PIN.

The Reassessment Cycle

When does Cook County reassess properties?

Cook County uses a triennial (three-year) reassessment cycle divided into three geographic regions. Each region is reassessed once every three years on a rotating basis. The City of Chicago is in Triennial 3, with reassessment years of 2021, 2024, and 2027. North and Northwest suburbs are reassessed in 2022, 2025, and 2028. South suburbs are reassessed in 2023, 2026, and 2029. The 2024 Chicago reassessment was the most recent; the next is 2027.

Do I have to wait for a reassessment year to appeal?

No. You can appeal your assessment through the Board of Review every year, regardless of whether your property is in a reassessment year. The Board of Review publishes an annual schedule of township appeal windows, and any property owner can file during their township's open window. You do not need to have received a Notice of Proposed Assessment to file with the BOR. If you missed the Assessor appeal window or simply want a second look, the BOR is available to you annually.

What does a reassessment notice mean?

A Notice of Proposed Assessment is exactly what it says — a proposal, not a final determination. It tells you the Assessor's preliminary assessment for your property and starts the clock on your 30-day window to file an appeal with the Assessor's office. If you do nothing within 30 days, the proposed assessment becomes final. If you file an appeal, the Assessor reviews your evidence and may adjust the value before certifying it as final.

Will my taxes automatically go up if my assessed value goes up?

Not necessarily in a proportional way. Tax rates are set based on total levy divided by total EAV in the district. If all properties in your taxing district rise by the same percentage, your share of the levy stays roughly the same and your bill may not increase dramatically. Your bill will likely increase if your assessed value rises faster than the average in your district, or if taxing bodies increase their levies. The relationship between assessed value and tax bill is real but not one-to-one.

The Appeal Process

How long does an appeal take?

Assessor-level appeals typically take 6–12 weeks from filing to decision, though timing varies. Board of Review appeals also typically take several months. The combined timeline from filing an Assessor appeal to receiving a BOR decision — if you pursue both levels — can range from 6 months to over a year. PTAB appeals can take one to several years. For most homeowners pursuing only the Assessor and BOR levels, total elapsed time is usually 6–12 months.

Can I appeal my assessment every year?

Yes, through the Board of Review. The BOR accepts appeals annually during each township's open window. You can file a BOR appeal every year if you choose. The Assessor-level appeal is only available when you receive a Notice of Proposed Assessment, which happens during your triennial reassessment year. But the BOR is always available annually, in every year.

What evidence do I need to appeal?

The two main categories of evidence are (1) comparable sales — recent arm's-length sales of similar properties near yours — and (2) property record errors — documented discrepancies between what the record card says and what is actually true about your property. A third option is a full appraisal from a licensed appraiser. Comparable sales are the most commonly used evidence. Three to five strong comparables that closed within 12 months and are within half a mile make for a solid appeal.

What are my chances of winning an appeal?

Success rates vary significantly depending on the quality of evidence and the specific circumstances. Appeals supported by a recent purchase price below the implied assessed value, or by clear comparable sales data, have strong prospects. Appeals filed without evidence or based on general unhappiness with taxes have poor prospects. Many Assessor-level appeals result in some reduction; the Board of Review also grants reductions in a meaningful proportion of cases it reviews. Having strong, property-specific evidence is the single biggest predictor of success.

Can the Assessor raise my assessment because I filed an appeal?

No. The Assessor does not raise assessments in retaliation for appeals, and there is no mechanism by which a good-faith appeal triggers an increased assessment. The Assessor's options are to reduce, maintain, or (in limited circumstances, such as if the evidence reveals an underassessment) adjust the value — but in practice, residential Assessor appeals result in a reduction or no change. The same is true at the Board of Review level.

Can I appeal both the Assessor and the Board of Review in the same year?

Yes, and this is the standard approach. File with the Assessor first (during the 30-day window from your notice). Then, regardless of the Assessor's outcome, file with the Board of Review during your township's open window. The BOR is an independent review body and is not bound by the Assessor's decision. You can — and often should — pursue both levels in sequence during the same tax year.

Filing Your Appeal

Where do I file a Cook County property tax appeal?

For the Assessor-level appeal, file online at assessor.cookcountyil.gov. In-person filing is available at 118 N. Clark Street, Chicago. For the Board of Review, file online at borc.cookcountyil.gov. The BOR also accepts in-person filings at 118 N. Clark Street, Suite 601. Both bodies have separate systems and separate filings — you cannot file for both through one portal.

What is the deadline to file?

The Assessor-level deadline is 30 days from the date printed on your Notice of Proposed Assessment. This is non-negotiable — late filings are not accepted. The Board of Review deadline is your township's specific appeal window, published annually on the BOR website. There is no universal date; each of Cook County's 38 townships has its own window, typically several weeks in duration. The PTAB deadline is 30 days from the Board of Review's decision letter.

Can I file an appeal online?

Yes. Both the Assessor and the Board of Review have robust online filing systems. Online filing is the most efficient approach — you can upload evidence documents directly, track your filing, and receive confirmation immediately. In-person filing is also available at 118 N. Clark Street for either body. There is no requirement to file in person or to work with an attorney for the Assessor or BOR levels.

Do I need a lawyer to appeal my property taxes?

Not for the Assessor or Board of Review levels. These appeal processes are specifically designed to be accessible to property owners representing themselves. A property tax attorney or consultant can be valuable for large or complex properties, for cases with significant potential savings that justify a contingency fee, or for PTAB appeals where formal proceedings apply. For a standard residential condo or single-family home, self-representation is common and often just as effective as hiring a professional.

What do property tax attorneys charge?

Most property tax attorneys and consultants who handle residential appeals work on a contingency basis. They take no fee if there is no reduction, and charge 33%–50% of the first year's savings if they win. Some also charge a modest flat fee to file regardless of outcome. For a property where the potential savings are $3,000/year, a 40% contingency means the attorney takes $1,200 and you keep $1,800 — plus you keep the full savings in all subsequent years until the next reassessment.

Results and Outcomes

What happens if I win my appeal?

Your assessed value is reduced to the value determined by the Assessor or Board of Review. This lower AV is then used in calculating your EAV, net EAV, and ultimately your tax bill. The reduction applies to the tax year in which you appealed. The lower assessed value carries forward automatically — you do not need to re-appeal every year to maintain it — until the next reassessment or until a new appeal is filed.

What if I win the appeal but my tax bill does not go down much?

This can happen for several reasons. Tax rates can increase even as assessed values decrease, partially or fully offsetting the benefit of a lower AV. Exemptions that were previously missing may be added, compressing the apparent impact of the assessment reduction. The equalization factor can also shift from year to year. A reduction in AV does reduce your relative tax burden — it shifts a smaller share of the total levy to you — even if the absolute bill does not drop as much as you might expect.

What if my appeal is denied?

A denial at the Assessor level does not foreclose further options. You may appeal to the Board of Review regardless of the Assessor's decision. The BOR conducts an independent review and is not bound by the Assessor's ruling. If the BOR also denies your appeal and you believe the assessment is still incorrect, you may appeal to PTAB within 30 days of the BOR decision. You may also re-appeal during next year's BOR township window with updated evidence if the market or your circumstances have changed.

Will I get a refund if I win?

Not typically at the Assessor or Board of Review levels for taxes already paid. The reduction applies going forward — specifically to the tax year in which you appealed. If you have already paid the second installment for that year based on the higher assessment, a refund from the Treasurer's office may be issued. For PTAB decisions, a credit or refund for the applicable tax year may be available. The mechanics depend on timing and when the bills were issued relative to the decision.

How long does the reduced assessment last?

A successful appeal establishes a lower assessed value that carries forward until the next reassessment of your triennial region. For Chicago properties, if you won an appeal on the 2024 assessment, that lower value carries forward through the 2025 and 2026 tax years. The next full reassessment is 2027, at which point the Assessor will re-evaluate the property from scratch. You can also re-appeal annually through the BOR if market conditions change or new evidence is available.

Exemptions

What exemptions are available in Cook County?

How do I apply for exemptions?

Applications for all Cook County exemptions are filed with the Cook County Assessor's Office at cookcountyassessor.com. The Homeowner Exemption is typically applied automatically for owner-occupants after the first year, but you should verify it is in place. The Senior exemptions require annual or periodic renewal. Veterans and disability exemptions require documentation of qualifying status.

Can I get retroactive exemptions if I missed them in prior years?

Illinois law allows homeowners to apply for certain missed exemptions retroactively for up to three prior tax years. This can result in a refund from the Treasurer's office. The Assessor's website has information on retroactive exemption applications. If you have owned and occupied your home for several years and discover the Homeowner Exemption was never applied, a retroactive application could be quite valuable.

Does the Homeowner Exemption apply automatically?

In most cases, yes — the Homeowner Exemption is applied automatically when the Assessor's records show a property is owner-occupied. However, it is not guaranteed, especially after a recent purchase (the Assessor's records may not be updated immediately), after a refinancing or title change, or if the property was previously listed as an investment property. Always verify that your Homeowner Exemption appears on your tax bill or Assessor record. If it is missing, apply immediately at cookcountyassessor.com.

Special Situations

I just bought my home. Should I appeal?

Check immediately. If the Assessor's implied market value (AV ÷ 0.10) is higher than what you paid, you have an excellent basis for appeal — your purchase price is the clearest possible evidence of market value. This situation is especially common for buyers who purchased during or shortly before a reassessment year. Even if you did not receive a Notice of Proposed Assessment, you can file a Board of Review appeal during your township's annual window. There is no requirement that you have received a notice to appeal through the BOR.

I own a rental property. Can I appeal?

Yes. All property owners in Cook County — regardless of whether the property is owner-occupied — have the right to appeal their assessment. Rental properties are assessed under the same framework as owner-occupied residential properties (at 10% of estimated market value for residential classification). The evidence approach is similar: comparable sales of similar investment properties in the area, or an appraisal. Note that the Homeowner Exemption and Senior exemptions do not apply to non-owner-occupied properties.

Is appealing a condo different from appealing a single-family home?

The process is identical, but the evidence is specific to property type. Condos should be compared against other condos in the same building or nearby comparable buildings — not against single-family homes. The Assessor's valuation model for condos may weight unit-level characteristics (floor, exposure, parking) differently than for houses. Make sure your comparable sales are true comparables: same building type, similar floor plan, similar amenities and building quality.

My home needs significant repairs. Does that affect my assessment?

Yes, and it can be grounds for appeal. If your property has deferred maintenance, structural issues, or condition problems that would reduce its market value relative to comparable properties in good condition, you can present photographic evidence and contractor estimates to support a lower value. The Assessor's mass appraisal model may not capture your specific property's condition. Documenting condition issues — ideally with photos and professional estimates — adds weight to your evidence package.

What if my neighbors have lower assessments for similar properties?

This is called a uniformity argument, and it is a legitimate basis for appeal even if your assessment is accurate as an absolute measure of market value. Illinois law requires that assessments be uniform — properties of similar characteristics and value should bear similar assessed values. If you can show that comparable properties in your neighborhood are assessed at a lower ratio to their market value than your property, you have a uniformity argument. You can look up your neighbors' PINs and assessed values on the Assessor's website.

I never received a Notice of Proposed Assessment. Can I still appeal?

Yes. The Board of Review does not require that you have received a Notice of Proposed Assessment. During your township's annual BOR window, you may file an appeal based on your current assessment. You can look up your current assessed value at any time on the Assessor's website using your PIN. If you believe the assessment is too high — regardless of whether you received a notice — you may appeal through the BOR.

The Complete Series

This FAQ is the hub post in the Camille Canales Group's Cook County property tax education series. Each article covers a specific aspect of the process in greater depth:

→ Chicago Property Taxes Explained: Key Dates, Tools, and Expert Help — The foundational overview of how Cook County property taxes work.

→ Cook County Reassessment Years: What Chicago Homeowners Need to Know — Deep dive on the triennial cycle, what reassessment does to your bill, and the 2024 Chicago reassessment.

→ How to Appeal Your Cook County Property Tax Assessment: A Step-by-Step Guide — Complete walkthrough of all three appeal levels with evidence guidance and common mistakes.

→ The Property Tax Appeal Checklist for Chicago Homeowners — Phase-by-phase checklist you can work through to verify your assessment, gather evidence, and file.

→ What a Successful Property Tax Appeal Actually Looks Like: A Logan Square Case Study — A detailed illustrative case study showing a full appeal from notice to $1,583/year in savings.

Camille Canales Group | Compass | ccg-chicago.com | 773-377-9200. This FAQ is for informational purposes only and does not constitute legal or tax advice. Cook County assessment procedures, deadlines, and exemption amounts are subject to change. Verify current information at assessor.cookcountyil.gov, borc.cookcountyil.gov, and cookcountytreasurer.com. Consult a licensed attorney or tax professional for advice regarding your specific property.