Cook County is reopening property tax appeals for 24 townships: what you need to know

Last updated 2026-07-10

What does it mean that Cook County is reopening appeals for 24 townships?

It means those townships just got new assessed values, and the clock on your appeal is running. Cook County does not reassess everything at once. The county works on a triennial cycle, rotating through three geographic groups: the City of Chicago, the north and northwest suburbs, and the south suburbs ^[1]. Roughly one-third of the county gets a fresh value each year.

When a township's reassessment notices go out, a 30-day appeal window opens with the Cook County Assessor's office. Close that window without acting and you still have a second shot at the Board of Review. Miss both, and you are stuck with the county's number until the next cycle.

So when the Assessor announces it is reopening appeals for 24 townships, it means those townships received new assessments, or the office is extending a window that closed before some owners saw their notices. Either way, the opportunity is real and time-limited.

For 2025, the Assessor posts reassessment schedules on its official site ^[1]. The 24 townships on the current list run through areas like Bloom, Bremen, Calumet, Lemont, Orland, Rich, Thornton, Palos, Worth, Lyons, Berwyn, Cicero, Proviso, and Riverside, spread across the south and near-west suburban rings. If your property sits in any of these townships, the window is open now or opens soon. Check your notice for the exact close date. That date is the law, not a suggestion.

Which 24 townships are included in this appeal reopening?

The Cook County Assessor publishes the reassessment and appeal schedule township by township at cookcountyassessor.com ^[1]. Which townships are open depends on which triennial group the Assessor is working through. For the south and near-west suburban group, the townships historically included are:

Township	Triennial Group	Typical Appeal Period
Bloom	South Suburbs	30 days post-notice
Bremen	South Suburbs	30 days post-notice
Calumet	South Suburbs	30 days post-notice
Lemont	South Suburbs	30 days post-notice
Orland	South Suburbs	30 days post-notice
Palos	South Suburbs	30 days post-notice
Rich	South Suburbs	30 days post-notice
Thornton	South Suburbs	30 days post-notice
Worth	South Suburbs	30 days post-notice
Berwyn	Near West	30 days post-notice
Cicero	Near West	30 days post-notice
Lyons	Near West	30 days post-notice
Proviso	Near West	30 days post-notice
Riverside	Near West	30 days post-notice
Stickney	Near West	30 days post-notice
Norwood Park	Northwest	30 days post-notice
Jefferson	Northwest	30 days post-notice
Lake	North	30 days post-notice
Leyden	Northwest	30 days post-notice
Maine	North	30 days post-notice
New Trier	North	30 days post-notice
Niles	North	30 days post-notice
Palatine	Northwest	30 days post-notice
Wheeling	Northwest	30 days post-notice

This list reflects townships historically covered in the Assessor's rotation of south and north suburban reassessments ^[1]. Confirm it against the official schedule, because the Assessor can adjust timelines. Your notice mailing date is the clock that matters legally ^[2].

Not sure which township your property sits in? Look at the top of your tax bill, or use the Assessor's property lookup tool at cookcountyassessor.com. You can also check your Cook County tax assessor tax bill to confirm the township on your account.

How does the Cook County appeal deadline actually work?

You get 30 days from the mailing date on your reassessment notice to contest your value with the Assessor. That date is printed on the notice itself. Illinois law sets the foundation: under 35 ILCS 200/16-55, "complaints that any property is overassessed or underassessed may be made by any taxpayer" ^[2]. The Assessor's rules turn that into the 30-day window.

Miss those 30 days and you move to round two, the Cook County Board of Review. The Board runs its own separate window, which opens after the Assessor's window closes and generally runs through late fall. You get 30 days from when the Board opens your township's docket to file there ^[3]. That is a real second chance. Plenty of owners who miss the Assessor still win meaningful reductions at the Board.

Miss both, and your next formal option is the Illinois Property Tax Appeal Board (PTAB), which hears appeals after the Board of Review rules. PTAB cases can run 18 to 36 months, so that path is slower and more work ^[4]. Most owners who catch the Assessor or Board window do better fighting there first.

Treat a reassessment notice like a filing deadline. Write the close date on a calendar the day it lands in your mailbox.

What is the triennial reassessment cycle and why does it create this schedule?

Cook County is the only Illinois county that uses a triennial (three-year rotating) reassessment system instead of the annual reassessment most counties run ^[1]. The county splits into three roughly equal groups by geography. Chicago gets reassessed one year, the north and northwest suburbs another, the south suburbs the third. Then it repeats.

This shapes your appeal strategy. Your one shot at the Assessor for a given value comes once every three years. The Board of Review and PTAB stay open after that, but the Assessor's window, generally the fastest and cheapest route to a reduction, only opens at reassessment time.

For 2024 and 2025, the Assessor is working through the south and near-west suburban triennial group ^[1]. That is why 24 townships from that area are open at once. Owners there received new values, and the 30-day windows opened on a rolling basis as notices went out.

If your township is not on the list, check whether you sit in the Chicago triennial or the north suburban triennial. Those groups run their own schedules and their own upcoming windows.

How much can you actually save by appealing in Cook County?

Enough to matter every year until your next reassessment. A large share of contested assessments end in reductions. The Board of Review reports handling roughly 300,000 to 400,000 appeals a year across the county, with residential owners getting reductions in a meaningful percentage of cases ^[3].

Here is the math. Residential property in Cook County is assessed at 10 percent of market value under Illinois law ^[2], so a $400,000 home carries an assessed value near $40,000. The Illinois Department of Revenue sets an annual equalization factor on top of that. For tax year 2023 the Cook County multiplier was 3.0163 ^[5], pushing the equalized assessed value (EAV) on that same $400,000 home to roughly $120,652. Knock 10 percent off the assessed value on a property paying an effective rate near 2 percent, and the owner saves around $240 a year, every year, until the next reassessment.

Academic work on Cook County has repeatedly found that homes in lower-income neighborhoods tend to be overassessed relative to their actual sale prices compared with higher-value neighborhoods, a pattern the Assessor's office has acknowledged and says it is working to correct ^[6]. That is not a guaranteed win. But if your assessed value looks out of line with what nearby homes actually sold for, you have real grounds to push back.

Filing costs nothing. Contingency firms typically take 25 to 40 percent of your first year's savings. On a $500 reduction, that is $125 to $200 handed to the firm. File yourself with solid comps and you keep the whole thing.

What evidence do you need to appeal a Cook County property tax assessment?

You need proof that your property's market value is lower than the assessment implies. Two kinds of evidence carry the weight.

The first is comparable sales. These are recent arm's-length sales of homes like yours in size, age, condition, and location. The Assessor prefers sales from the 12 months before January 1 of the tax year being assessed ^[1]. Pull them from the Cook County Clerk's recorded-deeds records, Zillow, Redfin, or Realtor.com, though the county's own records are the cleanest source ^[8]. Aim for three to five comps. The closer they match your square footage, lot size, and neighborhood, the stronger your case.

The second is a recent appraisal. A licensed Illinois appraiser produces a formal opinion of value that carries weight at both the Assessor and Board of Review levels. Residential appraisals in Cook County run roughly $300 to $500, so they make sense when the potential savings justify the cost.

For the Assessor's online portal, you upload a completed appeal form plus your evidence as PDFs ^[1]. No attorney needed. No firm needed. You need clean documentation of what similar homes sold for and a clear explanation of why your value is too high.

One thing surprises homeowners. You can also appeal on factual errors in your property record. Wrong square footage, wrong bedroom count, incorrect construction quality, any of those can cut your assessment without a single comp. Pull your property record from the Assessor's website first and check every field.

How do you actually file a Cook County Assessor appeal online?

You file through the Assessor's online portal at cookcountyassessor.com ^[1]. Here is the process in practice.

First, confirm your township's window is open. The Assessor's homepage posts current township schedules. Second, gather your evidence: comps, your property record printout, any appraisal. Third, create or log into your account. Fourth, find your property by PIN (Property Index Number, printed on your tax bill and reassessment notice). Fifth, pick your appeal reason, either comparable sales, an appraisal, or a property characteristic error. Sixth, upload your evidence as PDFs and submit.

You should get an email confirmation. The Assessor mails or emails a decision, usually within 60 to 120 days, though that can stretch. If they lower your value, the reduction applies to your next tax bill. If they deny it or hand you less than you think is fair, you can still file with the Board of Review during its separate window ^[3].

A few practical notes. The portal has had technical trouble during peak filing periods. File in the first two weeks of the window, not on the last day. Save screenshots of every upload confirmation. Keep copies of everything you submit. If the portal times out on you, the deadline does not move.

Want a structured walkthrough with fill-in forms, a comparables worksheet, and a submission checklist? The TaxFightBack appeal kit was built for this exact situation. It covers the Assessor's appeal and, if needed, the Board of Review follow-up.

What happens after you file with the Assessor's office?

The Assessor reviews your evidence against its internal valuation model, then does one of three things: accepts it and lowers your value, cuts it partway, or denies it.

You get a decision letter or email. If the Assessor grants a reduction, the adjusted value flows into the next tax cycle. Cook County bills taxes in arrears, so a successful 2024 assessment appeal typically affects your 2024 taxes, which are billed in 2025 ^[2].

Unhappy with the decision? File with the Cook County Board of Review. The Board's window for each township opens after the Assessor closes it and generally runs through November or December ^[3]. The Board is a three-member elected body that hears evidence independently of the Assessor. Filing is free. Reuse the same evidence packet, and add new comps if better sales data has surfaced.

After the Board rules, you can take an unfavorable decision to PTAB or to the Circuit Court of Cook County ^[4]. Both paths run slower and cost more, but they exist. Most homeowners who do the homework win real reductions at the Assessor or Board level and never go further.

Can you appeal at the Board of Review if you miss the Assessor's window?

Yes. This is one of the most useful facts about Cook County's system. Missing the Assessor's 30-day window does not end your appeal rights for the year. The Cook County Board of Review runs as a separate, independent body with its own window ^[3].

The Board opens a docket for each township after the Assessor closes its window for that township. You get 30 days from when the Board opens your township's docket to file. Under Board rules, residential owners can use the same comparable sales evidence they would have used at the Assessor level.

The Board handles a high volume of appeals every year. It generally issues decisions within 60 to 180 days of filing, though contested cases with hearings run longer. Contact and filing information is at cookcountyboardofreview.com ^[3].

One real difference between the venues: the Assessor allows amendments and informal back-and-forth before a decision. The Board is more formal. Submit your best evidence the first time. Do not assume you can supplement later.

What exemptions should you also check while your appeal window is open?

Appeals and exemptions are separate processes, but tackle both at once because both cut your bill. Many owners either never claim their exemptions or let them lapse without noticing ^[7].

The Homeowner Exemption reduces the EAV of your primary residence by $10,000. The Senior Citizen Exemption cuts another $8,000 if you are 65 or older. The Senior Freeze Exemption locks your EAV if your household income falls below the state threshold (recently $65,000; confirm the current figure at the Assessor's site). Veterans and people with disabilities have additional exemptions available.

Exemptions apply after your assessed value is set, so an assessment reduction and an exemption stack. A household that wins a $5,000 assessed value reduction and claims the Homeowner Exemption for the first time drops its EAV by $15,000 combined.

The Assessor's exemptions page at cookcountyassessor.com lists current eligibility rules and application forms ^[7]. Some exemptions need a one-time application; others renew annually. The Senior Freeze in particular requires yearly renewal and income verification.

What if your property is commercial or income-producing?

Commercial appeals follow the same triennial schedule and the same Assessor and Board of Review path, but the evidence standard is different. Commercial property is assessed at 25 percent of market value, versus 10 percent for residential ^[2]. The main valuation method for income-producing property is the income approach, meaning the Assessor models your value from rental income, vacancy rates, expenses, and cap rates.

For a commercial appeal, your evidence should include actual rent rolls, a current profit and loss statement, vacancy data for comparable space in your submarket, and ideally a cap rate analysis or an appraisal by a licensed Illinois appraiser. Sales comps can support the income analysis but rarely carry a commercial case alone.

Commercial is the one area where paying for professional help is worth weighing hard, especially for properties with complex income streams. On a $2 million assessed commercial property, the potential savings are large enough that a 30 percent contingency fee still leaves real money for the owner. That said, small commercial properties (small retail strips, two-to-four flats assessed commercially) are entirely manageable as a DIY appeal with proper income documentation.

What are the most common reasons Cook County appeals are denied?

Appeals fail mostly because the evidence does not move the needle against the Assessor's model. The recurring mistakes:

Comps that are too far away. A sale in a neighboring township or a different neighborhood does not establish your value. Stick to your immediate area, ideally within half a mile.

Comps that are too old. Sales from more than 12 to 18 months before the assessment date carry less weight. The Assessor models value as of January 1 of the tax year.

Ignoring condition differences. If your comp sold low because it was a distressed sale or needed major renovation, and yours is in good shape, the comparison collapses.

No adjustment for square footage. A 1,400-square-foot home is not a clean comp for a 2,100-square-foot home. Find truly similar properties, or make explicit per-square-foot adjustments in your submission.

Missing a factual error. If the Assessor's record shows a finished basement you do not have, or a garage that does not exist, a factual correction is the fastest path to a reduction and needs no comp analysis at all.

Submitting a form with no narrative. A spreadsheet of sale prices with no context does not tell the Assessor why those sales prove your value is wrong. Write two or three sentences on the appeal form explaining the comparison directly.

Frequently asked questions

When is the deadline to appeal my Cook County property tax assessment?

The deadline is 30 days from the date your township's reassessment notice was mailed by the Assessor's office. That date is printed on the notice. If you miss the Assessor's window, you can still file with the Cook County Board of Review within 30 days of when the Board opens your township's docket, which happens after the Assessor's window closes.

How do I know if my Cook County township is in the current appeal window?

Check the reassessment schedule posted at cookcountyassessor.com. The Assessor lists each township, its reassessment mailing date, and the appeal deadline. You can also look at your reassessment notice, which states the deadline directly. If you did not receive a notice but believe your township was reassessed, look up your property by PIN on the Assessor's portal.

What is the Cook County triennial reassessment and which townships are affected in 2025?

Cook County rotates reassessments across three geographic groups on a three-year cycle: Chicago, north and northwest suburbs, and south suburbs. In 2024 and 2025, the south and near-west suburban townships are being reassessed. That group includes Bloom, Bremen, Calumet, Orland, Palos, Thornton, Worth, Lemont, Berwyn, Cicero, Lyons, and related townships. The full list and exact dates are at cookcountyassessor.com.

Does filing a property tax appeal in Cook County cost anything?

Filing with the Cook County Assessor's office is free. Filing with the Cook County Board of Review is also free. If you hire a contingency firm, they typically charge 25 to 40 percent of the first year's tax savings. If you hire an attorney for PTAB or Circuit Court proceedings, expect hourly fees starting around $200 to $400 per hour. The DIY path costs nothing in filing fees.

Can I appeal my Cook County assessment if I already paid my tax bill?

Yes. Paying your tax bill does not waive your right to appeal. Cook County issues tax bills based on the prior year's assessed value, so your payment and your appeal are often on different timelines. If your appeal succeeds and results in a lower assessed value, the reduction generally applies to the next tax bill cycle rather than generating a refund for taxes already paid, though there are exceptions for Board of Review and PTAB refund orders.

How long does a Cook County Assessor appeal take to get a decision?

Decisions from the Assessor's office typically arrive within 60 to 120 days of filing, but during heavy appeal periods the timeline can stretch. Board of Review decisions generally take 60 to 180 days from filing. PTAB appeals are the slowest path and can take 18 to 36 months. File as early in the appeal window as possible to get your decision before the next tax bill is issued.

What comparable sales evidence works best for a Cook County appeal?

Use arm's-length sales of properties similar to yours in size, age, condition, and location, closed within 12 months before January 1 of the tax year being assessed. Aim for three to five comps within half a mile of your property. Pull data from the Cook County Clerk's recorded deeds or from major real estate platforms. Explain in writing why each comp is relevant and how it supports your claimed value.

What is the Cook County equalization factor and how does it affect my appeal?

The Illinois Department of Revenue sets an annual equalization factor (multiplier) for Cook County to bring assessed values in line with state standards. For tax year 2023, the factor was 3.0163. It is applied to your assessed value to produce the equalized assessed value (EAV), which is the base for calculating your tax bill. Lowering your assessed value through an appeal reduces your EAV proportionally, which directly cuts your tax bill.

Can I appeal my assessment and also apply for exemptions at the same time?

Yes, and you should. An assessment appeal and exemptions are separate processes, but both reduce your tax bill. The Homeowner Exemption cuts EAV by $10,000; the Senior Citizen Exemption adds another $8,000. Apply for any exemption you qualify for through the Assessor's exemptions page at cookcountyassessor.com. The savings from a successful appeal and a newly claimed exemption stack on top of each other.

What happens if the Assessor denies my appeal?

A denial from the Assessor does not end your appeal rights. You can file a separate appeal with the Cook County Board of Review during its open window for your township. The Board reviews evidence independently and can grant reductions the Assessor refused. After the Board rules, you can escalate to the Illinois Property Tax Appeal Board or Circuit Court, though those paths take significantly longer.

Do I need a lawyer or a property tax firm to appeal in Cook County?

No. The Assessor's online portal and the Board of Review both accept self-represented owner appeals. You need solid comparable sales evidence or documentation of a factual error in your property record. Lawyers and contingency firms make sense for complex commercial properties or PTAB proceedings, but for standard residential appeals, the DIY path costs nothing extra and keeps every dollar of savings.

How does a successful appeal affect future tax years?

A reduced assessed value from an Assessor or Board of Review appeal applies for the remainder of the triennial cycle, more than one year. If the Assessor reduces your 2024 assessed value, that lower value stays in effect until the next reassessment of your township, typically three years later. This means a single successful appeal can generate savings across multiple tax bills.

What is the Illinois Property Tax Appeal Board and when should I use it?

PTAB is a state-level administrative body that hears property tax appeals after the county Board of Review has ruled. You file a PTAB petition if you are unsatisfied with the Board of Review's decision. PTAB cases take 18 to 36 months on average and involve more formal rules of evidence. Most residential owners do not need PTAB if they prepare strong evidence for the Assessor and Board of Review stages.

Sources

1. Cook County Assessor's Office, official website and reassessment schedule: Cook County uses a triennial reassessment cycle; the Assessor posts township-by-township appeal deadlines and the online appeal portal
2. Illinois Compiled Statutes, 35 ILCS 200 (Property Tax Code), via Illinois General Assembly: Residential property in Illinois is assessed at 10 percent of market value; commercial at 25 percent; complaints of overassessment may be made by any taxpayer under 35 ILCS 200/16-55
3. Cook County Board of Review, official website: The Board of Review opens a separate 30-day appeal window for each township after the Assessor's window closes; the Board handles roughly 300,000 to 400,000 appeals annually
4. Illinois Property Tax Appeal Board (PTAB), official website: PTAB accepts appeals after the county Board of Review rules; cases can take 18 to 36 months to resolve
5. Illinois Department of Revenue, Cook County Equalization Factor announcements: The Cook County equalization multiplier for tax year 2023 was 3.0163
6. University of Chicago Harris School of Public Policy, research on Cook County assessment equity: Research has found that properties in lower-income neighborhoods tend to be overassessed relative to actual sale prices compared to higher-value neighborhoods, a pattern acknowledged by the Cook County Assessor
7. Cook County Assessor's Office, exemptions section: The Homeowner Exemption reduces EAV by $10,000; the Senior Citizen Exemption reduces it by an additional $8,000; the Senior Freeze Exemption is available to households with income below the state threshold
8. Cook County Clerk's Office, recorded documents and property records: The Clerk's office maintains public records of recorded property sales that can be used as comparable evidence in assessment appeals
9. Illinois Department of Revenue, Property Tax section: The Illinois Department of Revenue sets the annual equalization factor for each county; Cook County multipliers are published annually
10. Illinois General Assembly, 35 ILCS 200/16-55 (Complaints to assessors): Under 35 ILCS 200/16-55, complaints of overassessment may be made by any taxpayer; the statute establishes the basis for the 30-day appeal window