Best Illinois Property Tax Appeal Services in 2026 (Compared)
Last updated: April 27, 2026
Illinois has the highest average property tax bill in the Midwest at $4,947 per year on the median Illinois home of $239,000, driven by a 2.07% effective tax rate and the highest cumulative levies of any state in the region. Illinois property tax appeals are filed with your county Board of Review on a rolling basis as each township's assessment is published; you have 30 days from publication to file. Cook County, the highest-volume Illinois market, runs a separate process with its own assessor appeal phase before the Board of Review. Illinois assesses at 33.33% of fair market value statewide, but Cook County uses 10% for residential under its classification system, which materially changes the math for Cook filers. A successful Illinois appeal typically reduces market value by 8-15%, which on the median Illinois home saves $400-600 per year. With AppealDesk at $49 flat, a Cook County homeowner with a $5,000 annual tax bill keeps the full $400-600 reduction; with a 25% contingency service, the fee runs $100-150. The services below compare on pricing, coverage, and what you actually receive.
Rob Hartley·Updated April 27, 2026Check If You're Overpaying
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#1: AppealDesk - Best for Budget-Conscious Illinois Homeowners
AppealDesk provides an AI-generated evidence packet with comparable sales from your county, assessment-ratio context (Illinois uses 33.33% statewide; Cook County uses 10% for residential), Illinois-specific filing instructions for the appropriate Board of Review or Cook County assessor, and a cover letter. You pay $49 once and keep 100% of whatever reduction you achieve. The filing guide handles Cook County's separate process (assessor first, then Board of Review) versus the rest of Illinois (single Board of Review filing within 30 days of publication). Reported AppealDesk win rate in Cook County is 62%. Coverage spans every Illinois county.
Pros
- +$49 flat fee, the lowest price among paid services
- +All 102 Illinois counties covered, including Cook County
- +Cook County 10% classification ratio handled correctly in evidence
- +Comparable sales, assessment context, and Board of Review filing instructions delivered in minutes
- +Keep 100% of your savings with no contingency percentage
Cons
- –You file the appeal yourself using the step-by-step guide (10-15 minutes)
- –No hearing representation; Illinois Board of Review hearings are informal but you attend with the prepared evidence
- –No representation if you appeal further to the Property Tax Appeal Board (PTAB)
#2: Kensington Research & Recovery - Cook County Property Tax Specialist
Kensington Research & Recovery is a Chicago-based firm specializing in Cook County residential and commercial property tax appeals. They file at the assessor level and the Board of Review, and pursue PTAB appeals when warranted. Their 50% contingency on first-year savings is among the highest in the market, but they have decades of Cook County experience and strong relationships with the assessor's office. Best fit for Cook County homeowners who want zero involvement and have higher-value properties where the contingency math still leaves meaningful savings.
Pros
- +Decades of Cook County-specific experience
- +Strong assessor and Board of Review relationships
- +Full-service including PTAB representation when needed
- +Established Chicago-area firm
Cons
- –50% contingency is among the highest in Illinois
- –Cook County focused; limited value for downstate IL
- –On a typical Cook County reduction, fee can exceed $250-500
#3: Saranow Law Group - Cook County Property Tax Law Firm
Saranow Law Group is a Chicago-area law firm focused on Cook County residential and commercial property tax appeals. They handle assessor-level appeals, Board of Review hearings, and PTAB litigation. Their contingency structure varies by case complexity. Best fit for Cook County properties with complex assessment issues, properties likely to escalate to PTAB, or commercial properties.
Pros
- +Cook County-focused law firm with strong PTAB experience
- +Handles complex valuation disputes
- +Capable of escalating to Illinois Property Tax Appeal Board
- +Direct legal representation throughout the process
Cons
- –Contingency pricing not transparently published
- –Cook County focused; limited value elsewhere
- –Overkill for standard residential overvaluation
#4: Appeal.Tax - Cook County DIY-Plus Tool
Appeal.Tax provides a Cook County-focused appeal product that combines comparable-sales research with appeal-filing support. The product targets the same DIY-plus space as AppealDesk but is Cook County only. For Cook County homeowners choosing between Cook-only tools, AppealDesk's $49 flat fee covers the same core deliverables (Cook County 10% classification ratio applied correctly, comparable sales, filing instructions) at a transparent price, while also working in the other 101 Illinois counties.
Pros
- +Cook County-focused with knowledge of the local process
- +DIY-plus model means you retain control of the appeal
- +No full-service contingency on savings
Cons
- –Cook County only
- –Pricing not transparently published
- –Cook-specific product; less value if you have Illinois properties elsewhere
#5: Ownwell - Full-Service in Illinois
Ownwell handles the entire Illinois appeal process for you, including Cook County and select other Illinois counties: filing, informal review, and Board of Review hearings. Contingency means no upfront cost and no fee if no reduction. They report an 88% success rate. The 25% fee is competitive with the Illinois market, and on a typical Cook County reduction the fee usually runs $100-150 versus 50% with Kensington. Coverage outside Cook County varies; verify your specific Illinois county before signing up.
Pros
- +Zero effort, they handle filing and hearings
- +No fee if they do not save you money
- +25% contingency is competitive with the Illinois market
- +Cook County coverage with experience in the multi-step process
Cons
- –25% fee on Illinois reductions can exceed $100-200 per year
- –Coverage limited within Illinois; verify your county
- –You do not see or learn from the evidence used in your appeal
#6: DIY (No Service) - Free, Maximum Effort
You can file an Illinois Board of Review appeal entirely on your own. Pull comparable sales from your county website or Zillow, complete the Board of Review complaint form, and file within 30 days of your township's assessment publication. In Cook County, you also file at the assessor level first. The process is free. The trade-off is the time investment to research comparables, understand the 33.33% statewide ratio (or Cook's 10% classification ratio), and present evidence in a format the Board of Review will accept.
Pros
- +Free
- +You learn the process and can repeat annually
- +Full control over which comparables you use
Cons
- –Hours of comparable-sales research
- –Cook County's multi-step process is easy to miss
- –Easy to mishandle Illinois's assessment-ratio math
- –No structured filing guide
All Services at a Glance
| Service | Price | Model | Coverage | Best For |
|---|---|---|---|---|
| AppealDesk | $49 flat | DIY + evidence | All 102 IL counties | Budget-conscious, any IL county |
| Kensington | 50% of first-year savings | Full-service | Cook County primarily | Cook County hands-off |
| Saranow Law Group | Contingency (varies) | Legal representation | Cook + surrounding | PTAB-likely cases |
| Appeal.Tax | Contact firm | DIY tool + support | Cook County, IL | Cook-only DIY-plus |
| Ownwell | 25% of savings | Full-service | Illinois (+6 states) | Lower-fee full-service |
| DIY | Free | Self-research | Anywhere | Maximum effort, zero cost |
How to Choose the Right Service
Start with whether you are in Cook County. Cook runs a unique multi-step process: you file first at the assessor level (during your township's open period) and then optionally at the Board of Review, with the option to escalate to the Property Tax Appeal Board (PTAB) afterward. Cook also uses a 10% residential assessment-classification ratio, different from the 33.33% statewide ratio. If you are in Cook County, your evidence and filing math must reflect this. Outside Cook, you have one filing window with the Board of Review, 30 days from your township's assessment publication. Then consider pricing. Illinois has the highest property taxes in the Midwest, so even a modest 8-10% reduction translates to $400-600 in annual savings on the median home. The break-even between $49 flat fee and 25% contingency is roughly $196 in annual savings, which most Illinois reductions exceed. Compared to Kensington's 50% contingency, the math strongly favors flat-fee or DIY for most Cook County residential filers. Next, consider effort and escalation potential. Standard residential Board of Review appeals are designed for non-attorney filers; AppealDesk's $49 packet handles the evidence and filing steps. Cases likely to escalate to PTAB or that involve commercial properties benefit from a Cook County-focused law firm like Saranow. Hands-off filers in Cook County may prefer Ownwell over Kensington given the 25% vs 50% spread.
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