Your Property Tax Assessment Is Probably Wrong — Here's How to Appeal It

Odds are nobody from the county has ever been inside your house. Your assessment came from a mass-appraisal model — software that values thousands of properties at once from sales data and whatever the county's records say about you. It has never seen the cracked foundation. It doesn't know the basement it calls finished has been studs and a sump pump since 2019. It may be charging you for a bathroom you do not have.

That's not corruption. It's an estimate made at scale, and estimates made at scale are wrong constantly. The fix is an appeal — duller and more winnable than people expect. Property tax runs county by county, so every specific below varies; your assessor's site has the real ones.

Three numbers people mash together

• Market value — what your house would sell for.
• Assessed value — what the county taxes. In many states it's a set percentage of market value, not market value itself.
• The tax bill — assessed value, minus exemptions, times rates set by the schools, county, city, and every other body over your parcel.

You appeal the value. You cannot appeal the rate — that's set by elected bodies through budget votes. This is why most failed appeals fail: the owner arrives furious about a bill and argues about a number nobody in the room controls.

The deadline is short, and it is hard

This is the most important paragraph here. Your window typically opens when the assessment notice is mailed and closes within weeks — commonly something like 30 to 45 days, sometimes less. Miss it and you generally wait a full year. There is usually no appeal to the appeal.

And the notice looks like junk mail. Thin envelope, county seal, a number that isn't a bill and doesn't demand money. People throw it away, and that one motion costs them the year. Find out when notices go out where you live, and calendar the deadline.

Step 1: Pull your property record card

Before arguing about value, check the facts. Most counties post your property record card online behind a parcel search. It's the county's description of your house — what the model was fed. Read it against reality:

• Square footage — measured, not remembered. Errors here move the number most.
• Bedroom and bathroom count. A half-bath recorded as full, or a bathroom that exists only on paper.
• Basement: finished or unfinished, and how much.
• Lot size, and a garage that may have been torn down a decade ago.
• Year built, additions, and the condition grade — often stale by years.

Factual errors are the easiest win available: you're not arguing opinion, you're correcting a record. Real appeals get won on a phantom bathroom, sometimes with one call and a photo. Start here every time.

Step 2: Comparable sales

If the facts are right and the number still looks wrong, you need comps — sales of similar properties near you. Two rules trip up first-timers.

• The assessment date is usually not today. Most jurisdictions value as of a fixed date — often January 1, sometimes an earlier lookback. Sales near that date are what count. Current listings are the classic rookie error: an asking price is a wish, not a sale.
• Arms-length sales only. Foreclosures, short sales, family transfers — anything where both sides weren't free agents gets thrown out.

Aim for five or six of the closest matches, and be honest about the differences. Don't cherry-pick so hard it's obvious — a board that catches you hiding the three sales down the street stops believing everything else you brought.

Step 3: The uniformity argument

Here's the one most owners never learn. In many jurisdictions you can win without proving anything about market value — by showing you're assessed unequally against similar neighbors. Divide each comparable home's assessed value by its square footage, then do yours. If theirs land near $95 a foot and you're at $130, that's a uniformity claim: you're carrying more of the load than the house next door, whatever the right value is. Some states put this in statute, others honor it in practice, a few won't — check yours. Value and uniformity are independent theories of the same case, and you can often run both.

Evidence that actually moves people

• A recent arms-length purchase of the home itself — the strongest evidence there is. Bought it eight months ago for $340,000 and the county says $395,000? That's close to dispositive. Bring the closing statement.
• Dated photographs of defects: the foundation crack, the failing roof, water in the basement.
• Contractor estimates. A written bid for a $22,000 foundation job beats "it needs work" every time.
• A recent appraisal, if you already have one from a refinance. Don't buy one to appeal a modest assessment — it can cost more than the win.

Try the informal review first

Many assessors will adjust over the counter or by phone before any form gets filed. It's the fast path, and for factual errors it's often the whole ballgame. Call and say:

"Hi — I'm looking at the property record card for parcel [number], and I think there are factual errors on it. It shows three full bathrooms and a finished basement. We have two bathrooms, and the basement has never been finished. What do you need from me to correct the record?"

Calm, specific, factual — you're reporting a data problem, not accusing anyone. Then ask: "If we can't resolve it here, what's my deadline to file a formal appeal?" Write down the answer and who gave it.

The formal appeal

If that stalls, you file — with a board of review, a board of equalization, an assessment appeals board, whatever yours is called. Names vary; function doesn't. It's usually not a courtroom: often a folding table, three people, and fifteen minutes.

1. Bring comps on paper, in multiple copies. Don't make three volunteers squint at your phone.
2. Lead with your number: "The assessment is $395,000. I believe the correct value is $340,000, and here's why."
3. Facts first, comps second, uniformity ratio third. Then stop talking.
4. Argue value, not hardship.

That last one deserves bluntness. "I can't afford this" is not an argument the board is allowed to consider — their jurisdiction is the valuation, not your ability to pay. If money is the real problem, the next section is where it pays off.

Exemptions are the bigger win most people miss

An appeal is a fight about one year's number. An exemption comes off the top every year. For most homeowners it's worth more than a successful appeal — and many are not automatic. You have to apply.

• Homestead, for your primary residence. Widely available; amounts and rules vary enormously.
• Senior or over-65 — often the largest on the menu, and often missed. The assessor does not send a birthday card.
• Assessment freezes or caps, which lock your assessed value, not your rate. Often tied to age, sometimes income.
• Veteran and disabled-veteran exemptions — the disabled-veteran versions can be substantial, and in some states wipe out the bill entirely.
• Disability exemptions unconnected to military service.

Check the list once a year, and again after anything that could newly qualify you: turning 65, a disability rating, a move. Some jurisdictions apply a missed one retroactively, so ask: "Can this be applied retroactively, and how far back?" The worst answer is no.

Should you hire someone?

Property tax consultants typically work on contingency — a share of your first year's savings, commonly between a quarter and half, nothing if they lose. Worth it for a high-value property or a complicated valuation. Usually unnecessary for a straightforward appeal, especially the best kind, where the win is a factual error. Nobody needs half your savings for pointing out that the bathroom isn't there.

What happens after

If you escrow taxes with your mortgage, a win doesn't reach your monthly payment when the board rules. Servicers recalculate at an escrow analysis, typically once a year, so the savings arrive on their clock. Escrow is its own animal. Don't budget the win into next month.

And if you lose, appeal again next year. Assessors reassess on a cycle, and each new assessment is a new number with a new window and new comps. Meanwhile the record card you corrected stays corrected. A no costs you a year, not the argument.

The order of operations, on one screen

1. Find your deadline first. The assessment notice is not junk mail.
2. Pull the record card. Check every fact against your actual house.
3. Fix factual errors informally, by phone.
4. Still wrong? Build comps: arms-length sales, near the assessment date, honestly chosen.
5. Run the uniformity check — assessed value per square foot, yours against your neighbors'.
6. Bring photos, contractor bids, and your purchase price if it's recent. On paper.
7. At the board: your number first, facts second, brief. Value, never hardship.
8. Then claim every exemption you qualify for, and check again every year.

The quiet scandal of property tax isn't fraud. It's that very few owners ever appeal, while a meaningful share of those who do get something. The county isn't hiding it — the record card is public, the deadline is printed on the notice, the exemption list is on the website. The system just assumes you won't look. Look.