Property Taxes

How to Appeal Your Property Tax Assessment, Step by Step

By Aritz Boveda · Updated October 21, 2026
Fact-checked against primary sources on October 21, 2026

You can appeal your property tax assessment if the assessor’s value for your home is higher than what it would sell for, or if the county’s records about your home are wrong. The appeal is filed against the assessed value, not the tax bill, and the deadline usually runs from the date on your assessment notice, often only about 30 days. Every dollar of value you remove saves you that dollar times your tax rate, so a $30,400 reduction at a 2.4% rate is worth about $730 a year.

When an appeal makes sense

An appeal is a value argument. The board doesn’t care that your taxes went up or that the bill feels unfair. It wants evidence that the number on your notice is wrong. That usually means one of three things:

1. The market value is too high. Recent sales of similar homes nearby point to a lower price than the assessor used.
2. The property record has errors. The county lists the wrong square footage, an extra bathroom, a finished basement you don’t have, or the wrong lot size. Cook County’s assessor lists incorrect square footage and classification errors among the reasons to appeal.
3. Your home is assessed out of line with its neighbors. Some places let you argue “lack of uniformity”: similar homes on your street carry lower assessments per square foot than yours.

If the assessor’s value is within a few percent of what you could realistically sell for, the savings may not justify the time. Cook County’s assessor, for example, says that if your property details are correct and the value is within 10% of what you think the home is worth, an appeal is unlikely to change your bill much. A clear error, such as 250 square feet you don’t have, is usually worth fixing.

Before you start, pull up how the bill is built. Our guide on how property tax is calculated explains assessment ratios, exemptions and mill rates, which you’ll need to estimate your savings.

Deadlines: the part people miss

There is no national deadline. Each state, and often each county, sets its own window, and missing it usually means waiting a full year. A few official examples:

The safest rule: the day your assessment notice arrives, find the deadline printed on it or on the assessor’s website and put it on your calendar. Don’t wait for the tax bill. By the time the bill shows up, the appeal window for that year has often closed.

What evidence works

Strong cases are short, organized and built on numbers.

Comparable sales. Find three to five homes that sold recently, close to your valuation date, in your neighborhood, and similar in size, age, style and condition. Cook County’s assessor, for example, asks for comparables in your neighborhood that closely resemble your home in size and style. Convert each to a price per square foot so the board can compare quickly. Your county’s online records, a local real estate agent, or a recent appraisal are common places to find them.

Errors in the property record. Download your property record card from the assessor’s website and check every line: living area, bedrooms, bathrooms, basement finish, garage, lot size, year built. Measure if you need to. Note that some assessors measure from the exterior walls; Cook County says it measures the exterior perimeter, so your interior room measurements may come out smaller. A survey or a recent appraisal is stronger proof than your own tape measure.

Condition problems. Foundation cracks, a failing roof or water damage that a buyer would price in. Bring dated photos and repair estimates from contractors.

A recent purchase price. If you bought the home in an arm’s-length sale near the valuation date, your closing statement is often the single best piece of evidence.

The process, step by step

Most places use a similar sequence, though the names of the offices vary.

1. Read your notice. Confirm the market value, the assessed value and the appeal deadline.
2. Check your record card for factual errors. Simple corrections are sometimes fixed without a formal hearing.
3. Ask for an informal review. Many assessors will meet or talk by phone before you file anything formal. Bring your comparables. If the assessor agrees, the value can be corrected at this stage.
4. File the formal appeal on time with the county board (it may be called a board of review, appraisal review board, value adjustment board or assessment appeals board). Cook County notes that its appeals are free to file online and don’t require a lawyer. Ask your county whether a filing fee applies.
5. Prepare a one-page summary. List your value, the assessor’s value, and each comparable with address, sale date, price, square footage and price per square foot. Attach photos and documents behind it.
6. Attend the hearing in person, by phone or online, or submit written evidence if your board allows it. Keep it short: explain why the value is wrong and point to the evidence. Who must prove what varies: in California, for example, the assessor generally carries the burden on an owner-occupied home that has the homeowners’ exemption, as long as you’ve given the assessor the information the law requires, while owners of rentals and second homes carry it themselves.
7. Get the decision in writing. If you disagree, most states allow a further appeal to a state board or court, with its own deadline. Texas, for example, gives owners 60 days after receiving the review board’s written order to file in district court, and generally requires paying at least part of the tax to keep that appeal alive.
8. Keep paying your tax bill while the appeal is pending, unless your county tells you otherwise, to avoid penalties. If you win after paying, ask how refunds are issued.

Before the hearing, ask the board whether it can also raise a value on review and whether you can withdraw your appeal. Rules differ from place to place.

Worked example: what a successful appeal saves

Here’s a homeowner in a county that taxes 100% of market value, with a combined rate of 24 mills (2.4%) and a $25,000 homestead exemption.

• Assessor’s market value: $380,000, based on a record listing 2,150 square feet.
• Actual living area, confirmed by a survey: 1,900 square feet.
• At 1,900 square feet, the assessor’s value works out to $200 a square foot.
• Three nearby comparable sales: $178, $184 and $189 per square foot. The middle figure is $184.
• Supported value: 1,900 × $184 = $349,600.

The reduction of $30,400 saves $729.60 in the first year. If the county only reappraises every three years and the value carries forward, that’s about $2,188.80 over the cycle, before any rate changes. The exemption doesn’t change the savings: it comes off both versions equally, so the saving is simply the value reduction times the rate.

Before you file

Treat the appeal like a short business case. Gather the notice, the record card, three to five comparables and any photos or repair estimates in one folder. Check the deadline twice. If the numbers show your value is close to right, it may be smarter to confirm your exemptions instead: a missing homestead exemption can cost more than a modest overassessment. When in doubt about local rules, call the assessor’s office.