28. Is Your Property Over-Assessed? How to Find Out and Appeal

28. Is Your Property Over-Assessed? How to Find Out and Appeal gives you a clear, step-by-step way to understand what drives your bill, what to verify on your notice, and what to do if the numbers look off.

Getting a property tax bill that seems too high can be frustrating. You may suspect your home is over- assessed (its assessed value exceeds its true market value), meaning you’re paying more tax than necessary. Here’s how to check your assessment and, if needed, appeal it. Signs Your Property May Be Over-Assessed

• Assessment vs. sale price: If you recently bought the home, or have comparable sales nearby,

compare those sale prices to your assessed value. For example, if a very similar house on your block sold for $250,000 but your assessed value is $300,000, that’s a red flag. In general, if “market value for tax purposes exceeds the amount for which [you] could sell the property,” experts say you should appeal.

• Neighbor comparisons: Look up a few neighboring properties (same size/age) in your county’s

assessor database or a site like Zillow. If your taxes are significantly higher despite similar features, you may be over-assessed. This is known as a “lack of uniformity” issue.

• Assessment ratio: Some areas allow a tolerance margin. For instance, Chicago’s assessor suggests if

your assessed value is within 10% of market value, an appeal might not gain much. But beyond that, it’s often worthwhile. In fact, nationwide studies suggest only about 7–8% of homeowners appeal, even though roughly half of properties could be over-assessed. If any of the above applies, you might indeed be over-assessed. How to Confirm Your Assessment

• Use public records and tools: Many county assessor websites allow you to search by address. Find

your latest assessed value (often on an annual notice or roll). Then gather comparable sales (comps) from real estate sites or county recorder data. Compare square footage, lot size, and upgrades.

• Check property details: Sometimes assessments use outdated or incorrect data (wrong square

footage, missing garage, etc.). Make sure the assessor’s description of your property is accurate. Errors can inflate your assessment.

• Calculate the implied value: Some states use an assessment ratio (e.g. 20% of market value). If

your area has a known ratio, you can back-calculate the market value implied by your assessment. If it’s unrealistically high, that’s a clue. How to Appeal an Over-Assessment

• Review deadlines: Each locality has an appeals window (often a few months each year). For

example, California counties require appeals to be filed within 12 months of the damage or destruction 23 (see natural disaster section) – but for general appeals, many counties have specific annual filing periods (check with your assessor). In Cook County, Chicago, for instance, appeals open shortly after reassessment notices go out. Missing the window usually means waiting another year. 5

• File a formal appeal: Appeals are typically free. You submit evidence to your local Board of Review

(or equivalent, sometimes called an Assessment Appeal Board). You’ll state your opinion of the home’s value and include supporting documents. Useful evidence includes recent comparable sales, a recent appraisal, photos of needed repairs, or an inspection report. (The WBEZ guide notes that you can even do simple appeals in about 20 minutes online in Cook County 16 .)

• Free tools and counsel: If you need guidance, PropTaxHelper’s site offers a free checklist for

appeals. We also partner with tax consultants who can advise you pro bono on gathering comps or filling out forms. Even if you handle the appeal yourself, our IRS-free “Appeal Prep Workbook” (downloadable at PropTaxHelper.com) can help structure your argument. During an appeal, be factual and courteous. Focus on the evidence (comps and data). If you built a case showing your property’s fair market value is lower than the assessor’s, there’s a good chance they will lower your assessment. Remember: the appeals process is designed to be taxpayer-friendly. You have the right to challenge an assessment that’s too high. Bottom line: Over-assessments are common, and the appeal process is straightforward and cost-free

. It takes just a bit of homework — collecting comparable sales or photos of problems — to make a 16 persuasive case. Given that nationwide only a small fraction of people appeal 22 , you might find this step is surprisingly effective. If you believe your home’s assessed value is too high, don’t hesitate to file a protest. For more detailed guidance, see PropTaxHelper’s “Appeals 101” guide or join our community forum. Taking action could lower your tax bill next year substantially.

Next steps

• Use the Property Tax Estimator to sanity-check your bill.
• If something looks off, run a quick Appeal Savings scenario.
• Scan the Articles list for related topics like exemptions, deadlines, and escrow planning.