If your property's assessed value looks higher than what your home would sell for, you generally have a right to ask for a review. Specific evidence is usually necessary to support a challenge; a bill that simply feels too high is rarely enough. The steps below describe the common shape of an appeal in the United States. Forms, deadlines and hearing rules are set locally, so treat this as a roadmap for what to expect and prepare, and follow your own assessor's published instructions.
The Tennessee State Board of Equalization, for example, explains that the person appealing carries the burden of proving the correct value, that a claim of overvaluation without evidence of a more correct value is generally not enough, and that for residential property comparable sales are usually the best evidence. Other states differ in the details but follow a similar logic.
Pull your property record card, often online through the assessor's website, and verify the basics: living area, bedrooms and bathrooms, lot size, stories, garage, basement, age and condition. A record that lists a finished basement you do not have, or a larger lot than yours, can raise the assessment for reasons unrelated to the market. If you find an error, ask the assessor's office how to correct it. Some offices offer an informal review before any formal appeal, though an informal review may not protect your formal appeal rights, so ask about that at the same time.
Before you argue that a number is too high, know what the number is. In many places assessed value is a percentage of market value. Divide the assessed value by the ratio to get the market value the assessor implies. Example: an assessed value of $28,500 at a 10% ratio implies a market value of $285,000. If similar homes nearby are selling for around $255,000, that gap is the start of a case. Depending on local law, the grounds for appeal can include market value, incorrect physical facts, unequal treatment compared with similar properties, or the wrong classification, so read your jurisdiction's list.
Look for recent sales of similar homes near yours: similar size, age, condition, lot and bedroom count. Three to five good comparables are usually more persuasive than a long list of loose matches. Your county's online records, the assessor's sales data and public listing sites are all possible sources, though some boards prefer a specific source. Adjust honestly for differences. A comparable with a renovated kitchen is not a clean match for a home with the original one, and a board may set aside sales that are not explained.
A recent independent appraisal, dated photographs of damage or deferred maintenance, contractor estimates for needed repairs, and documents showing something unusual about the property (a busy road, an easement, a flood-zone designation) can all help. The aim is a clear, organized file that a reviewer who has never seen your house can follow in a few minutes.
Appeal windows are often short, commonly measured in weeks from the date the assessment notice is mailed, and the exact period varies by state and sometimes by county. In Tennessee, for example, the State Board publishes specific dates, and a late filing generally means waiting for the next cycle. Check the date on your notice the day it arrives, before you start gathering evidence.
Many places have two stages: an informal conversation with the assessor, and then a formal appeal to an independent board of review or equalization. The formal stage normally involves written evidence and a hearing, which may be in person or remote. Submit the paperwork exactly as instructed, keep copies, and note the hearing date.
An appeal does not automatically pause your bill. The Tennessee State Board advises taxpayers to pay at least the undisputed portion before the delinquency date to avoid penalties. Ask your local office what applies, and remember that a mortgage escrow account may pay the bill without asking you.
The board can uphold the assessment, reduce it, or in some places raise it if the hearing shows the value was too low. If you disagree with the result, many states allow a further appeal to a state board or court, which usually has stricter procedures and a shorter fuse. If you win, ask when the new value takes effect and whether it changes only future bills.
Suppose a home is assessed at $285,000 at a 100% ratio with an 18.5 mill rate, giving $5,272.50 a year. Three well-matched comparable sales average about $258,000. If the board accepts a value of $258,000, the tax becomes 258 x 18.5 = $4,773.00, a saving of $499.50 per year. If you expect to stay for five years and the reduction carries forward, that is roughly $2,500, which is worth an afternoon of preparation. Use the calculator to run the same comparison with your own numbers.
Arguing about the tax rate. An assessment appeal is about the value, classification or facts of your property. The rate is set through budgets and votes, so a board of review usually cannot change it.
Relying on an online estimate. A listing-site estimate is not an appraisal or a sale. Use actual closed sales with dates and prices.
Comparing different things. A larger home on a bigger lot in a different school district is not a comparable. Explain each adjustment in a line or two.
Missing paperwork. A late form or missing signature can end an appeal before it begins. Keep a copy of everything and note the date you filed.
Your notice and record card; a one-page summary stating the value you believe is correct and why; three to five comparable sales with address, sale date, price, size and condition; photographs dated and labeled; any appraisal or repair estimate; and a short list of the facts you want corrected. Bring several copies if the hearing is in person, and arrive early.
Some companies handle appeals for a fee, often a share of any savings. That can make sense if you do not have time, but the process is designed so a homeowner can handle it directly, and a paid service has to produce the same kind of evidence. Read the fee terms before you sign.