Property Tax Appeal Success Rate: What the Data Actually Shows

Before investing time in a property tax appeal, most homeowners want to know: what are the odds? Is this worth doing, or is the assessment essentially final once it's issued?

The answer depends heavily on your jurisdiction, the quality of your evidence, and whether you understand what the appeal board is actually evaluating. Here's what the data shows.

The Baseline: Most Jurisdictions Show High Success Rates for Well-Filed Appeals

Across US jurisdictions, the appeal success rate for properly documented residential appeals — where the homeowner brings genuine comparable sales or identifies a factual error — runs well above 50%. In many high-volume appeal markets, the numbers are considerably higher.

Texas: In Harris County alone, over 350,000 property owners filed protests in a recent year. The Harris County Appraisal District resolves a significant portion of these through its iSettle online settlement system before a formal hearing. Homeowners who file with appropriate comparable sales or condition evidence and engage the informal review process consistently secure reductions. The data shows that the plurality of protests that reach formal ARB hearings result in some reduction, and that the majority of protests that are settled informally result in the property owner retaining some or all of their requested reduction.

Cook County, Illinois: The Cook County Assessor's Office processes hundreds of thousands of appeals annually. A 2022-2023 analysis by the Cook County Treasurer found that appeals reduced assessed values by billions of dollars in aggregate. The success rate for residential appeals that are properly filed and include comparables from the same neighborhood is consistently high — particularly for appeals arguing "lack of uniformity," where the homeowner only needs to prove their property is assessed higher per square foot than similar neighboring properties.

New York: SCAR (Small Claims Assessment Review) proceedings in New York result in reductions in the majority of cases that reach a hearing before a trained hearing officer. However, New York requires homeowners to first exhaust the grievance process with the Board of Assessment Review, which denies many cases — meaning the homeowners who reach SCAR have already been filtered to those with plausible claims.

What Separates Successful Appeals from Failed Ones

The appeal success rate data masks a critical variable: the quality of the evidence submitted. The failure rate is not driven primarily by legitimate overassessments being correctly denied — it's driven by homeowners submitting the wrong evidence, missing the procedural requirements, or using invalid comparables.

Studies and forum data consistently identify the same failure modes:

Using Zillow/Redfin estimates as evidence: Automated valuation models are rejected by every assessment board. They cannot assess interior condition, do not meet appraisal standards, and are not prepared by licensed professionals. Homeowners who rely on these tools rather than actual comparable sales data fail not because the board disagrees with the value — but because the evidence doesn't meet the board's minimum evidentiary standard.

Using weak or cherry-picked comparables: A comparable sale from a different school district, a significantly different size range, or a foreclosure sale will be immediately dismissed. Worse, one weak comp in a package of otherwise solid evidence causes the board to discount the entire package. One experienced appellant summarized the dynamic: "The moment they catch one cherry-picked comp, they discount every other comp on your sheet, even the solid ones."

Arguing overvaluation when uniformity is the correct argument: In jurisdictions like Cook County, the most accessible appeal strategy is lack of uniformity — proving that your home is assessed at a higher rate per square foot than similar neighbors, regardless of broader market trends. Homeowners who instead try to prove the market has declined often face an uphill battle in stable or rising markets. The uniformity argument only requires proving mathematical inequity, not broader market movement.

Missing the deadline: No evidence quality compensates for a missed filing deadline. The appeal is dismissed, the assessment is final, and the homeowner must wait a full year to try again.

Average Savings from a Successful Appeal

When appeals succeed, the savings are real and recurring — the reduction typically carries forward into subsequent tax years until the next major reassessment cycle.

Typical residential appeal outcomes by jurisdiction:

• Texas residential: Average reductions of 5% to 15% of assessed value are common in well-documented cases. On a $500,000 home in Harris County with a combined tax rate of 2.5%, a 10% reduction saves $1,250 per year — and that savings repeats every year until the next reassessment.

• Illinois (Cook County): The triennial reassessment cycle means a successful appeal locks in a lower value for three years. Average reductions of 10% to 20% of assessed value are documented in the Treasurer's reports. On a $300,000 assessed value at a 2% rate, a 15% reduction saves $900 per year — or $2,700 over the three-year cycle.

• New York (SCAR): Reductions from SCAR proceedings vary widely depending on how far above market the original assessment was. Cases with strong professional appraisals or clear comparable sales evidence often achieve 10% to 25% reductions.

• Florida: Appeals to the Value Adjustment Board (VAB) are less common in Florida because the Homestead Save Our Homes cap limits assessment increases for existing homeowners. But for recently purchased properties — which are reassessed at purchase price — market corrections can produce appeals with significant reductions.

The Factual Error Category: Near-Certain Success

The highest success rate category — by a significant margin — is appeals based on factual errors on the property record card. When a homeowner proves through objective documentation (blueprints, a licensed appraiser's measurement report, photographs) that the county has the wrong square footage, a phantom finished basement, or a phantom improvement that was never built, the assessor has no defensible position. The data is wrong. The assessment is mathematically incorrect.

These cases are resolved administratively in many counties without even requiring a formal hearing. The error correction letter is reviewed, the data is fixed, and the assessment is adjusted. When these cases do go to a hearing, the board almost universally rules for the homeowner — there is nothing to argue against a factual measurement correction.

What Happens If You Lose?

A denied appeal is not the end. Most jurisdictions allow escalation after a denial:

• Texas: Binding arbitration or district court after an adverse ARB decision
• Illinois: Escalation to PTAB (Property Tax Appeal Board) within 30 days of the Board of Review decision
• New York: SCAR or Tax Certiorari after a denied grievance
• Florida: Circuit court after a denied VAB petition
• California: Assessment Appeals Board decision can be appealed to the California Office of Tax Appeals or superior court

For residential homeowners, escalation beyond the first administrative level is typically only economically viable if the potential savings are substantial. The more common response to a denial is to regroup, improve the evidence package, and appeal in the next cycle.

Is It Worth Doing?

Run a simple calculation: take your current assessed value, multiply by your jurisdiction's effective tax rate, and then calculate what a 10% reduction would save per year. In most US jurisdictions with property tax rates above 1.5%, a 10% reduction on a home assessed above $250,000 saves at least $375 per year. In high-tax jurisdictions like Texas, New Jersey, Illinois, or Connecticut, the same reduction on the same home saves considerably more.

If the potential annual savings exceed a few hundred dollars and you have access to comparable sales data — which is publicly available in most counties — the time investment of a few hours is almost always justified.

The Property Tax Assessment Appeals Kit provides the evidence framework, comparable sales grid, and jurisdiction-specific deadlines that separate successful appeals from unsuccessful ones. The success rate isn't about luck — it's about submitting the right evidence, in the right format, before the right deadline.