Home / Washington
Washington taxes your home at full market value, so a win goes straight to your bill.
We check individual addresses here. We pulled 20 real King County homes and every single one is taxed on exactly its market value, to the dollar. There’s no cap in between. A 10 percent reduction on a $700,000 home is worth about $675 in the first year. 22 percent of homeowners who took an appeal to a decision in 2024 won a reduction.
So Washington decides these on market value, which means the evidence is recent sales of genuinely comparable homes. What really matters is whether that whole set of sales sits below your assessed value. If they bracket your assessment instead of falling under it, boards usually side with the assessor, because nothing's been clearly disproved.
Now a few things lose almost everywhere. Comparing your assessment to a neighbor's assessment usually doesn't count where the argument's market value. One sale on its own can pretty easily be dismissed as an outlier. And the size of your increase, or the size of your bill, isn't really evidence about what your home's worth.
July 1 or 60 days from the date on your value notice, whichever is later. King County mails in neighborhood waves from May through November.
Miss it and you generally wait a year, so honestly the date matters more than the paperwork does.
And wherever you are, the single most useful thing you can actually do today is go find your assessment notice and read the date printed on it. That's what starts your clock, it's usually a much shorter window than people expect, and there's no getting it back once it's gone.
We've built pages for King County and Seattle, using the county's own hearing record, and our free check works for King County houses.
First, look up your own record. Your county assessor's website shows your home's value and its details. Washington taxes homes on their full market value and there's no cap in between, so a lower value really does lower your bill.
Next, know where to file. You file a petition with your county's Board of Equalization by July 1 or within 60 days of the date on your value notice, whichever's later. The petition can't just say the value's too high. It has to say specifically why, or it gets thrown out as incomplete. There's a box on the form asking the assessor to send you their information, and it's free, so it's worth ticking it.
Then bring the evidence that wins here. Washington decides these on market value, so the evidence is recent sales of genuinely similar homes. Comparing your assessment to a neighbor's assessment isn't allowed as evidence here at all. In King County, about three in four winning homeowners won because the assessor agreed before the hearing, so it's really worth sending your evidence early.
Also, check your exemptions. If you're 61 or older, or disabled, and under the income limit, the senior and disabled persons exemption can take a big piece off your bill. You apply with your county assessor, and the limits change, so check their current table.
So type your address into our free check and we'll read the county's own records, work out whether the evidence actually supports an appeal, and tell you straight. Most people who use it get told not to bother, which is the point.
Check your Washington home, free
We've screened all fifty states and DC on the same two questions. Does winning a lower market value actually lower your bill, or is there a cap sitting in between? And can you even put the evidence together from public records?
This comes from our own fifty-state screen, where we checked each state's cap, whether sale prices are public, whether there's an argument based on assessed values, and how many appeals actually get filed. Where we've quoted an appeal count, it's from the state or county that published it. If you spot an error, please write to hello@propertytaxbuddy.com and we'll correct it and say what changed.