275 Seattle homeowners took a property tax appeal to a decision in 2024, and 79 of them got a reduction. That's 28.7 percent, against 22.1 percent for King County as a whole, so you're doing a bit better here than most.
Seattle homeowners do somewhat better than the rest of the county, though seven in ten of them still walk away with nothing. It isn't a formality anywhere. And Seattle's also the only city in King County with enough decided appeals to give a number that's worth trusting. Bellevue had 124, Kirkland 59, and it falls away pretty fast from there, so we don't publish rates for those.
Seattle's 2026 levy rate is $9.91 per $1,000 of assessed value. And the typical winning appeal in King County took $146,000 off, which works out to about $1,447 off your bill in the first year, and that holds until your next value notice moves it.
Of the 79 homeowners who won a reduction, 59 of them, about 75 percent, won because the assessor recommended the reduction rather than because the board overruled them.
Now the county's record labels those two things separately, so you can actually count them. And it changes what you should actually do, because your evidence is worth the most early, in front of the person who set your value, rather than saved up for a hearing.
First, attach your evidence when you file. Washington lets you submit it up to 21 business days before the hearing (WAC 458-14-066), and the county's own petition form recommends sending it as soon as possible, because that raises the chance of a reduction offer without a hearing at all. Next, check the box asking for the assessor's information. It's right there on the form, it doesn't cost anything, and it obliges the assessor to send you the comparable sales they're planning to rely on.
Basically the board's looking at whether the whole range of your comparable sales sits below the assessed value. So when an owner's sales run from say $830,000 to $904,000 and the county has the home at $972,000, those sales support a lower value and they don't support the assessment. That's a winning case.
But when the combined range of both sides' sales covers the assessed value as well as the owner's number, the board sustains, because nothing's been clearly disproved. Washington requires "clear, cogent and convincing" evidence to overcome the assessor's value (RCW 84.40.0301), and that's a really high bar compared to an ordinary dispute.
However, a few things lose reliably, and these are the board's own words. Comparing your assessment to a neighbor's assessment isn't admissible at all, and King County's own instructions say so plainly. Price per square foot has been called "generally not a reliable method for the valuation of single-family homes." A single comparable sale "may reflect an outlier value and, thus, cannot represent an entire market." An aging roof counts as normal maintenance rather than damage. And the size of your increase, or your tax bill itself, isn't evidence about market value.
But one thing that does work is photographs of specific defects. In a 2026 case, photos of cracked window frames led the assessor to lower the home's condition rating outright.
A petition that says only that your value is too high gets thrown out as incomplete (WAC 458-14-056). The reasons box has to say something specific about why the number doesn't reflect what the home would actually sell for.
Washington gives you until July 1 or 60 days from the date on your value notice, whichever is later (RCW 84.40.038). King County uses the 60-day version and mails notices in neighborhood waves from roughly May through November, so Seattle deadlines are staggered across the year by area rather than all falling on one date.
And our free check reads the county's own appeal system and gives you your exact date for your parcel, along with whether the comparable sales actually support a case.
Every figure here comes from the King County Board of Equalization's 2024 Clerk's Record of Hearing, with property type and city looked up per parcel in King County's public parcel layer. Single-family homes only. The reasoning comes from Washington State Board of Tax Appeals decisions at bta.wa.gov. There's more on the method on the King County page.