To win a property tax appeal, you have to show the assessor’s number is wrong and back it with evidence the review board can verify: a corrected property record card, three to five recent comparable sales, and documentation of any defects that lower your home’s value. Roughly 40 to 60 percent of appeals result in a reduced assessment, and successful appellants typically see cuts of 10 to 15 percent. Those are decent odds if your case is real, and most homeowners handle the process without a lawyer.
Start With Your Property Record Card
The easiest reductions come from fixing wrong data. Every assessment is built on a property record card that describes your home’s physical characteristics, and errors on that card mean the valuation is built on facts that aren’t true. Common problems include overstated square footage, wrong lot size, an extra bedroom or bathroom that doesn’t exist, a finished basement that isn’t finished, a missing flood-zone notation, or a quality grade that doesn’t match the home’s actual condition.
Pull your card from the county assessor’s website or request it in person. Walk through every line against what you actually own. Measure the house if the square footage looks off, and photograph anything the card describes incorrectly. Straightforward factual errors can often be corrected with a phone call or an office visit, without any formal appeal at all.
Pick the Argument That Fits Your Facts
When the issue goes beyond bad data, most appeals rest on one of three arguments. You can raise more than one in the same petition, but each has to be supported on its own.
Market Value
A market-value argument says the assessor set your home higher than a willing buyer would actually pay. This is especially common after a local downturn, when assessments based on older sales haven’t caught up with falling prices. You’ll need recent comparable sales or a professional appraisal showing similar homes moving at lower numbers.
Assessment Inequity
An inequity argument doesn’t fight the market value directly. It says your property is assessed at a higher percentage of market value than comparable homes nearby. If your house is assessed at full market value and a near-identical neighbor’s is at 80 percent, you’re carrying more than your share of the tax base.
External Obsolescence
Sometimes your home loses value because of things you don’t control: a new highway ramp, a commercial development next door that adds noise and traffic, environmental contamination in the area, or rezoning that changes the neighborhood’s character. These off-site conditions are called external obsolescence, and if the assessor ignored them, you have grounds to push the number down.
Build the Evidence That Actually Persuades
A vague complaint that your tax bill is too high will not move a review board. Specific, verifiable evidence will. This is where appeals are won or lost.
Comparable Sales
Comps are the backbone of most appeals. You want three to five recent sales of homes similar to yours in size, age, condition, and location. Stay inside the same neighborhood or subdivision when you can, and keep the sales within the past six to twelve months. The county assessor’s office maintains sales records, and many publish them online. For each comp, present the address, sale price, sale date, and key features so the board can see why the comparison holds.
A Professional Appraisal
An appraisal from a licensed appraiser gives you a certified opinion of value and carries real weight at a hearing. Expect to pay $300 to $500 for a standard residential appraisal. In most jurisdictions, the appraisal should comply with the Uniform Standards of Professional Appraisal Practice; one that doesn’t may carry less weight or draw a challenge from the assessor’s representative.
Defects and Repair Estimates
If your home has structural damage, a failing roof, foundation cracks, outdated electrical or plumbing, or other conditions that hurt marketability, document them. Photos, written repair estimates from licensed contractors, and inspection reports translate a general complaint into a concrete number. A cracked foundation with a $15,000 repair bid is a specific dollar reason for the board to lower your value.
The Assessor’s Own Data
Before the hearing, ask the assessor’s office for the data used to value your property. Most jurisdictions require them to share it: the comps they relied on, the mass-appraisal formulas or models, and any adjustments applied specifically to your home. Once you can see where their numbers come from, you can aim your evidence at the exact places your case and theirs diverge, rather than guessing.
Try the Informal Review First
Before filing a formal petition, ask the assessor’s office for an informal review. Most jurisdictions offer one, and it can resolve the dispute faster and with less paperwork than a full hearing. You sit down with an appraiser from the office, present the same evidence you would take to a board, and often get a decision the same day or within a few days.
An informal review doesn’t waive your right to file a formal appeal if you’re not satisfied. Treat it as a low-risk first attempt. If the assessor agrees with your data, they can correct the valuation without a board getting involved. If they don’t, you’ve at least learned their position and can prepare a stronger formal case.
One warning: pursuing an informal review does not extend your formal appeal deadline. If you spend weeks negotiating and miss the filing window, you lose your appeal rights for the year. Track both timelines at once.
File the Formal Petition on Time
If the informal route doesn’t get you there, you file an official appeal form, called a Petition for Review, Notice of Protest, or Appeal of Assessment depending on where you live. The form is usually available on the county assessor’s or board of equalization’s website.
You’ll list your property identification number (on your tax bill or assessment notice), the assessor’s current value, and your own opinion of value based on the evidence you’ve gathered. You’ll also choose the grounds: market value, inequity, factual error, or a combination. Some jurisdictions want your evidence attached to the petition; others accept it closer to the hearing.
Deadlines are strict. Most states require filing within 25 to 60 days of the assessment notice, and review boards generally have no authority to grant extensions. Miss the date and you almost always forfeit your appeal for the entire tax year. Check the back of your assessment notice or your county’s website for the exact deadline and file well before it.
Many jurisdictions accept electronic filings; if you use the portal, save the confirmation number. If you file by mail, use certified mail with a return receipt so the filing date is documented. Filing fees, where they apply, typically run $15 to $300 for residential properties.
Win at the Hearing
After the petition is filed, you’ll get written notice of a hearing before a Board of Equalization, Board of Review, Appraisal Review Board, or a similar body. Hearings are less formal than court, but they follow a clear order: you present first, the assessor’s representative responds, and the board may question either side.
Present Your Case
Keep it organized and evidence-driven. Walk the board through each comparable sale, explain why it supports your value, and point out any errors on the property record card. If you have an appraisal, present its conclusions clearly. Bring extra copies of every document: one set for the board, one for the assessor’s representative, and one for yourself.
In most jurisdictions the burden of proof sits with you. You need to show the assessor’s value is wrong, not just that you wish it were lower. Present the pieces as a single argument: here are five comparable homes that sold below my assessed value, here are photos of deferred maintenance the assessor didn’t account for, here is the contractor’s estimate to fix it. The more specific the presentation, the harder it is to rebut.
Respond to the Assessor
The assessor’s representative will defend the current number, usually with their own comps, an explanation of the mass-appraisal methodology, or an argument that your comps aren’t truly comparable. Listen and be ready to answer. If their comps are older, farther away, or less similar than yours, say so on the record.
Exchange Evidence Early
Some jurisdictions require both sides to exchange evidence seven to fourteen days before the hearing. Even where it isn’t required, requesting the assessor’s evidence early gives you time to build counterarguments. Ask what the local rules are and use them.
Keep Paying Your Taxes During the Appeal
Filing an appeal does not pause your tax obligation. Keep paying on time. Skip a payment and you’ll face penalties and interest regardless of how the appeal turns out, and in many jurisdictions non-payment gets the appeal dismissed outright. If you win, you’ll receive a refund for the overpayment, sometimes with interest.
Know the Downside Before You File
In some jurisdictions, the review board can raise your assessment if the evidence, from either side, shows the property is worth more than the current valuation. A weak appeal against a strong assessor presentation can leave you with a higher tax bill than you started with.
The risk is small if you’ve done the work. A case built on solid comps and documented defects rarely triggers an increase. But if your assessed value is already close to market and you’re filing on general frustration rather than evidence, the math may not favor you. Look at your evidence honestly first. If you can’t make a clear case for a specific lower number, waiting for a year when the data supports you is a reasonable choice.
After the Decision
The board typically issues a written decision within a few weeks to a few months. It will sustain the original value, reduce it, or in some cases raise it. A reduction means your tax bill is recalculated and you receive a refund or credit for any overpayment. If the board rules against you, most states allow escalation to a higher body such as a state tax commission, property tax court, or district court, generally within 30 to 60 days of the written decision. Those proceedings are more formal, evidence rules are tighter, and many homeowners who reach that stage bring in a property tax attorney.
For a straightforward residential case built on a factual error, a handful of strong comps, or a clear market decline, the process above is one most owners can run themselves. Win it on the evidence.