How to appeal a property tax assessment

1. Read the notice, find the deadline

Appeals run against the assessed value, not the tax rate — you cannot appeal the levy. The notice of assessment states a deadline, usually 30–45 days from mailing (Texas: May 15 or 30 days after the notice; Cook County: a per-township window; Florida: 25 days after the TRIM notice). Miss it and you wait a year.

2. Check the record card for plain errors

Pull your parcel on the assessor's site. Wrong square footage, an extra bathroom, a finished basement you don't have, a garage that burned down — factual errors are the fastest wins and often fixed without a hearing.

3. Comparable sales

Three to five sales of similar homes (size, age, neighborhood) in the 6–12 months before the assessment date, at prices below your assessed value. A recent appraisal or your own purchase price also counts. Listing prices do not.

4. Uniformity

Even if your value is right, you can argue neighbors with similar homes are assessed lower. Many boards accept this "equity" argument; some states (Illinois, Ohio) weigh it heavily.

5. File and, if needed, go to the board

Most counties take appeals online. Informal review with the assessor's staff comes first; then a board of review / appraisal review board hearing, then a state board or court. Hearings take 10–15 minutes: state the value you want and hand over the evidence. Winning 5–15% is common; boards rarely raise a value in response to an appeal, but check your state.

Should you hire someone?

Contingency firms take 25–50% of the first year's savings. Worth it when the bill is large and you don't want to gather comps; not needed for a record-card error.