Somewhere in a kitchen drawer or a pile of unopened mail, millions of American homeowners have a property-tax assessment notice they never questioned. The number on it may be wrong, and not in their favor. A National Bureau of Economic Research working paper by economists Carlos Avenancio-León and Troup Howard, which examines racial disparities in property-tax assessments using administrative records, documents along the way that formal protest rates among residential property owners are remarkably low, even when comparable sales in a neighborhood suggest assessed values are too high. Yet among those who do push back, the success rate is striking: research tracking thousands of appeals in one of the country’s largest tax jurisdictions found that homeowners who submitted basic comparable-sales evidence frequently won reductions that cut their annual bills by hundreds of dollars.
That gap between how few people appeal and how often appeals succeed points to a quiet, expensive problem. Eligible homeowners are leaving real money on the table, year after year, often because they assume the process is rigged, too complicated, or not worth the effort.
The stakes are higher than usual as of spring 2026. Reassessment cycles completed across dozens of counties in 2024 and 2025 have pushed assessed values sharply upward in many markets, reflecting the pandemic-era surge in home prices. In places like Maricopa County, Arizona, and several fast-growing counties in Texas and Florida, homeowners have reported assessment increases of 20 percent or more in a single cycle. For anyone who received a notice this spring, the window to file an appeal is often measured in weeks, not months.
Why so few homeowners file
The NBER paper, whose primary focus is documenting how property-tax assessments fall disproportionately on minority homeowners, also sheds light on why protest rates remain so low. Drawing on administrative records rather than surveys, the authors identified several barriers that keep participation down. Many homeowners simply do not realize they can challenge an assessment. Others assume the process requires a lawyer or that the review board will rubber-stamp whatever the assessor decided. The time cost of gathering evidence, even when that evidence is straightforward, deters people who are already stretched thin.
There is also a knowledge gap about what counts as persuasive evidence. In most jurisdictions, the core of a successful appeal is a short list of recent sales of comparable properties (often called “comps”) that sold for less than the assessed value on the notice. County assessor websites, GIS portals, and consumer real-estate platforms like Zillow or Redfin can supply this data. But homeowners who have never navigated those tools may not know where to start, and the jargon on assessor websites does not always help.
What the Cook County data actually show
One of the few peer-reviewed analyses that traces appeal outcomes through official county records was published in the Columbia Journal of Tax Law, using data from Cook County, Illinois. Cook County is a useful test case: it is one of the nation’s largest property-tax jurisdictions, with effective residential tax rates that often exceed 2 percent of market value, and its appeal process is well-documented in public records.
The researchers found that a meaningful share of residential appellants received reductions when they submitted packets containing recent comparable sales and basic property details like square footage, lot size, and condition. One notable finding: homeowners who filed on their own, without hiring an attorney or a tax-appeal firm, frequently obtained reductions comparable in scale to those achieved by represented filers.
That does not mean professional help never matters. Research published in the National Tax Journal suggests that representatives can secure larger or more consistent outcomes in complex cases, such as mixed-use properties or homes with unusual features that make comps harder to identify. But for a straightforward residential appeal where the comparable sales clearly support a lower value, the Cook County data indicate that self-filing can work.
To put the savings in concrete terms: in a jurisdiction with a 2 percent effective tax rate, a homeowner who successfully reduces an assessed value from $350,000 to $325,000 would save roughly $500 per year. Over a decade in the same house, that is $5,000, and the reduction often carries forward until the next reassessment cycle.
Important limits on the evidence
Cook County is not the whole country. Appeal procedures, hearing formats, and burden-of-proof standards vary by state and sometimes by individual county. In Texas, homeowners file protests with county appraisal review boards under rules set by the state comptroller; Harris County, one of the few large jurisdictions that publishes annual protest statistics, has reported that a majority of residential protests result in some reduction. In New Jersey, appeals go to county tax boards or, for larger disputes, the state Tax Court. Win rates observed in one jurisdiction do not automatically apply in another.
Comprehensive, up-to-date national data on appeal outcomes remain hard to find. The International Association of Assessing Officers (IAAO) publishes standards and occasional surveys, but no single database tracks residential appeal success rates across all U.S. counties. The academic papers cited here summarize trends from institutional records in specific places, and homeowners looking for their own county’s track record may find limited or no public reporting.
Timing also matters. The most recent academic analyses draw on data collected before the sharp run-up in home prices that began in 2020. Whether appeal success rates have shifted during a period of rapid valuation increases is an open question. Rising assessments could mean more homeowners have legitimate grounds to appeal, but review boards may also be less inclined to grant reductions when broad market data support higher values. Without updated large-scale studies, the precise national picture as of May and June 2026 remains uncertain.
One more caveat worth noting: in states with assessment caps, such as California under Proposition 13, annual increases in assessed value are limited by law regardless of market conditions. Homeowners in those states may have less reason to appeal unless their property was recently purchased or reassessed at a value they believe exceeds fair market price.
How to file a property-tax appeal
While procedures differ by jurisdiction, the general steps are consistent enough to outline. Homeowners who believe their assessment is too high can typically follow this sequence:
- Review the assessment notice carefully. Check the property details (square footage, lot size, number of bedrooms and bathrooms) for errors. Factual mistakes are the easiest grounds for a correction and sometimes do not even require a formal hearing.
- Gather comparable sales. Look for three to five recent sales of similar homes in the same neighborhood. County assessor websites, MLS records, and consumer platforms like Zillow or Redfin are common starting points. Focus on properties that are genuinely comparable in size, age, condition, and location. Sales within the past six to twelve months carry the most weight.
- Check the filing deadline. Most jurisdictions set a window of 30 to 90 days after the assessment notice is mailed. Missing the deadline usually means waiting until the next reassessment cycle, which could be one to four years away depending on the state. Deadlines are typically listed on the notice itself or on the county assessor’s website.
- Submit the appeal. Many counties now accept online filings. The form generally asks for the property address, the owner’s contact information, the reason for the appeal, and supporting evidence. Attach the comparable-sales data and any documentation of property-condition issues (such as needed repairs or environmental problems) that might justify a lower value.
- Attend the hearing, if required. Some jurisdictions schedule informal reviews before a formal hearing. Bring printed copies of the comps and be prepared to explain, briefly and clearly, why the assessment exceeds market value. Keep the presentation factual; review boards respond to data, not frustration about tax rates in general.
One common concern: can filing an appeal cause the assessed value to go up? In most states, the answer is no for residential properties during the appeal itself, but rules vary. A handful of jurisdictions reserve the right to review the entire assessment upon appeal, which could theoretically result in an increase. Homeowners should confirm their jurisdiction’s policy before filing. The county assessor’s office or a local taxpayer-assistance hotline can usually clarify.
Who benefits most from appealing
Not every homeowner with a rising assessment is being overcharged. In many markets, higher valuations simply reflect genuine increases in sale prices. The research supports a narrower claim: when an assessment is out of line with what comparable properties actually sold for, and when the homeowner is willing to navigate the process, the odds of a favorable adjustment can be substantial.
Homeowners most likely to benefit include those whose property has a condition issue (deferred maintenance, flood damage, proximity to a busy road or commercial site) that comparable sales do not reflect, those in neighborhoods where recent sales have lagged behind the broader market, and those whose assessment notice contains factual errors in the property description. In each case, the appeal rests on specific, documentable evidence rather than a general feeling that taxes are too high.
The policy concern raised by both the NBER and Columbia studies is that information gaps and procedural complexity discourage many eligible households from ever testing their odds. Lower-income homeowners and those in communities with fewer civic resources tend to appeal at the lowest rates, even though they may stand to gain the most relative to their household budgets. Closing that participation gap is as much a question of outreach and simplification as it is of individual initiative.
The clock is running on spring 2026 appeal windows
For anyone who received a 2025 or 2026 assessment notice and suspects the number is too high, the single most important step is checking the filing deadline. Everything else, from gathering comps to filling out the form to preparing for a hearing, follows from that.
County assessor websites are the best starting point. Most list the appeal deadline, the required forms, and instructions for submitting evidence. Homeowners who want additional guidance can contact their local taxpayer advocate office or, in states that have them, a property-tax ombudsman. Paid services exist as well, but the Cook County data suggest that for a straightforward residential case, a self-prepared packet of comparable sales is often enough.
The savings may not be dramatic in every case. But for a homeowner paying property taxes for 10, 20, or 30 years on the same house, even a reduction of $200 to $500 a year compounds into thousands of dollars over time. The research is clear that most people who could benefit never try. Whether that changes as assessments keep climbing depends, in large part, on whether homeowners realize the odds are better than they think.
Warren Cohen is a finance writer based in Phoenix, Arizona, covering personal finance topics including credit, banking, and beginner investing. He earned his degree in business administration from Arizona State University and began his career working in consumer finance, where he gained direct experience with lending and credit systems. He now writes for personal finance websites and fintech platforms, focusing on clear, practical content that helps readers make informed financial decisions.
