My Property Assessment Jumped — Should I Appeal?

You opened the envelope, and the number is bigger. Sometimes a lot bigger. Assessment notices are landing in mailboxes across the country right now — Philadelphia mailed its 2027 values this summer, Florida's TRIM notices arrive in August, and Texas homeowners just finished protest season staring at increases of their own.

Here's the first thing to understand: a higher assessment is not automatically a wrong assessment. Home values have genuinely risen in most markets. The question that matters isn't "did my number go up?" — it's "does my new number exceed what my home would actually sell for, based on real sales of comparable homes?"

That question has a factual answer, and you can get it before your appeal window closes.

The 15-minute triage

Before you decide anything, do three things:

1. Find your new assessed value and your deadline. The notice itself lists both. Deadlines are unforgiving — most counties give you 30 to 90 days from the notice date, and missing it means waiting a full year while paying taxes on the inflated number. If you've misplaced the notice, your county assessor's website lists your value, and our county-by-county deadline table tracks verified filing deadlines.

2. Check what your assessment implies your home is worth. In some jurisdictions the assessed value is the market estimate. In others, it's a percentage of market value (an "assessment ratio"). Your county's rules are on the notice or the assessor's site — or covered in our county guides.

3. Compare against real sales. Not your neighbor's opinion, not a listing price — actual recent sales of homes similar to yours in size, age, and location. If similar homes sold for meaningfully less than your assessment implies, you likely have a case. If they sold for more, an appeal probably isn't worth your time — and knowing that quickly is valuable too.

What "meaningfully less" means

Small gaps usually aren't worth fighting. Assessors and review boards work with ranges, and a 2–3% difference rarely moves anyone. The cases worth filing typically show the assessment running 5–15% (or more) above what comparable sales support. On a $400,000 home with a 1.5% tax rate, a 10% over-assessment costs you roughly $600 every year it goes uncorrected — and those years compound.

There's a second angle worth checking: uniformity. In many states, you can appeal if your home is assessed higher than similar nearby homes are assessed, even if your market value looks defensible. If the notice shocked you, odds are decent that identical homes on your street got different numbers.

What an appeal actually involves (less than you think)

The process varies by county — that's the annoying part — but the shape is consistent:

1. A form. Usually one or two pages: your parcel number, your opinion of value, and why.
2. Evidence. Three to five comparable sales is the standard packet. Photos and repair estimates help if your home has condition issues the assessor can't see.
3. A deadline. The only unforgivable mistake.
4. Sometimes a hearing. Many counties decide residential appeals on paper. Where hearings happen, they're typically 10–15 minutes and informal — not a courtroom.

Most counties charge nothing to file a residential appeal. Nationally, studies have found that a large share of appeals succeed — the National Taxpayers Union has estimated that only about 5% of homeowners appeal, while as many as 30–60% of properties are over-assessed.

The honest decision framework

• New value at or below what comps support? Don't appeal. Enjoy the accurate assessment.
• New value 5%+ above comps, deadline open? File. The math strongly favors an hour of effort.
• Not sure which one you are? That's the most common situation — and it's checkable. Enter your address in the checker on this page and you'll get your assessment compared against recent nearby sales, your county's deadline, and an honest read on whether you have a case — with every source cited. It's free, and "no case" is a real answer we give often.

One more thing while you're here: many counties offer exemptions (homestead exemptions especially) that reduce your taxable value regardless of any appeal. If you've never applied, that's sometimes worth more than the appeal itself — check your county's assessor site or our county guides for what's available where you live.

The notice sitting on your counter has a clock attached to it. Spend the 15 minutes now.