How to Check Your Property Assessment and Decide Whether to Appeal

Every homeowner gets some version of the same piece of mail. It tells you what the local assessor believes your house is worth, and it arrives with a deadline that most people don't read until after it has passed.

It's tempting to shrug at that notice and save your complaints for the tax bill. The notice is the moment you can do something, and by the time the bill comes it's usually too late. Rules differ widely from state to state and county to county, so treat what follows as a general map and not legal advice. Your assessor's website has the version that applies to you.

You are appealing the value, not the tax

Your tax bill is broadly your assessed value multiplied by a rate set by local government. An appeal deals with the first number only. Arlington County, Virginia, spells this out on its appeals page: saying your taxes are too high is not grounds for appeal. King County, Washington, is just as blunt, and lists personal hardship and the amount of tax owed among the things its board won't consider.

That rules out a lot of angry letters. What is left is a narrower question, which is whether the assessor has your home's value wrong, and whether you can prove it.

Start with the property record

Before you think about market values, look up your home's record, which most assessors publish online. Check the square footage, bedroom and bathroom counts, lot size, and anything listed as a finished space or an improvement. These records are built from permits and old data, and they can be wrong. If yours says three baths and you have two, that's a real problem and an easy one to show.

A factual error like that can sometimes be fixed by a call to the assessor's office, with no formal appeal at all. I'd start there every time, since it costs nothing and an assessor's staff would generally rather correct a record than hold a hearing about it.

Find your deadline today

Deadlines are short, and they vary more than you'd guess. Worcester County, Maryland, has given owners 45 days from the notice date. King County's deadline is the later of July 1 or 60 days after the value notice was mailed, and its notices go out anywhere from May to November. Arlington's notices arrive in January, with appeal dates printed on them.

Your notice should tell you, so don't throw it out. If you've lost it, the assessor's site or a phone call will. Miss the date and you've generally lost your chance until the next assessment, and late appeals tend to be allowed only in narrow circumstances.

Build the case with real sales

In most places the assessor's number is presumed correct, and the burden falls on you. King County says so outright. You need evidence, and the best kind is recent sales of homes like yours.

Look for homes close by, similar in size, age and condition, sold near the valuation date your jurisdiction uses. Arm's-length sales are the ones that count, meaning the buyer and seller weren't related and the price wasn't a favor. A house sold to a cousin tells the board nothing.

Add anything that lowers your home's value and that the assessor wouldn't know from a desk. Good examples include contractor estimates for a failing foundation or roof, photos of the damage, and maps showing a busy road or limited access. Be specific about what's wrong and what it would cost to fix.

Here's a local quirk to watch for. Arlington accepts an argument that similar homes were assessed differently from yours, which it calls inequitable appraisal. King County says it won't consider comparisons with other properties' assessments at all. The same argument can be persuasive in one county and worthless in the next, which is why reading your own board's rules comes before anything else.

The part nobody warns you about

An appeal invites the assessor to look at your home again, and that can backfire. If someone visits and notices the shed on a permanent foundation or the finished basement that never made it onto the record, your value can go up. Before you file, walk around your own property and ask what a careful stranger would add to the list.

You should also weigh the effort honestly. If a successful appeal would trim your bill by a small amount, it may not be worth a paid appraisal, although you can still present free evidence yourself. An independent appraisal makes more sense when good comparable sales are scarce and the possible saving is large.

What happens after you file

The process usually has levels. Arlington's runs from the assessment office to a Board of Equalization and then to the circuit court. King County sends petitions to its board, where a hearing may be six months or more away, and owners can attend by phone or ask for a review of the written materials. A decision comes within 45 days of the hearing, and either side can take it to the state's Board of Tax Appeals.

If you win, you'll usually see a revised bill or a refund, and that can take a couple of months to arrive. Keep paying your taxes on time in the meantime unless your local rules say otherwise, because an open appeal doesn't always stop penalties.

So check the record this week, even if you have no plans to appeal. It's twenty minutes of reading, and you may be paying for a bathroom you don't have.