King County property tax appeals
Paying property tax on a value your home doesn’t have?
King County property tax appeals are the only thing we do. We screen every residential assessment in the county, find the ones the public record says are set too high, and appeal them to the Board of Equalization on your behalf. You pay only if your bill comes down.
Who we write to
Most King County assessments are close. Yours may not be.
If you got a letter from us, it’s because the county’s own records point to a lower value for your home. We screened every residential parcel in King County for 2026, more than 511,000 of them, and wrote to fewer than one owner in 500. We don’t write to homes that look fairly assessed, and we don’t take on cases the public record doesn’t support.
County records as of September 4, 2026. How we calculate these figures, and what we do with public records.
Why now
The county’s median is fair. Your parcel may not be.
The county sets values once a year from the prior year’s sales. For 2026 it lowered most of them, about as much as the market fell. But a median hides a wide spread, and nearly a quarter of homes that sold in 2025 and 2026 are now assessed above what their owners paid.
Our analysis of King County Department of Assessments public records as of September 4, 2026 (arm’s-length residential sales, price per square foot; median change between the 2025 and 2026 assessments across 450,782 residential parcels). Method and sources. Not every property is over-assessed. We check yours specifically before we ever suggest an appeal.
The process
Three steps, and we do the work in all three.
Appealing is your right, and it’s free to file. It’s also a government petition with a hard deadline that most people never get around to. That’s the part we take off your plate.
We review your assessment
We compare your county value against recent sales of similar homes nearby and against the Board’s own record of what it has reduced. If the evidence doesn’t clearly support an appeal, we tell you, at no charge.
We build and file the case
You sign a short agreement and the county’s one-page authorization. We build the evidence and file the petition before your deadline.
We see it through
Where the rules allow, we ask the Board to decide on the written evidence, so in most cases you don’t attend a hearing. If the Board reduces your assessment, your 2027 tax bill goes down, since a 2026 assessment sets your 2027 taxes.
What it costs
Nothing, unless we lower your bill.
- No upfront cost and no filing fees. If your assessment isn’t reduced, you owe us nothing.
- Our fee is 25% of your first-year tax savings. Every later year’s savings are entirely yours.
- Nothing is charged until the Assessor actually posts the reduced value to the tax roll, and you get an itemized statement at least 10 days before any charge.
- We only take cases where the evidence supports a reduction, so our incentive and yours point the same direction.
A worked example
| County assessment | $1,500,000 |
| Reduced by the Board to | $1,300,000 |
| First-year tax reduction (at a 1.05% levy rate) | $2,100 |
| Our fee (25%) | $525 |
| You keep, in year one | $1,575 |
“Tax savings” means the tax at the old assessed value minus the tax at the new one, using the levy rate actually applied to your parcel for that year. The engagement agreement uses the same definition.
Who’s behind this
A small Seattle firm that reads the record.
Rainier is based in Seattle and built on years of data analysis and real-estate analysis. We started it after noticing how many King County homes are assessed above what their own recent sale, or the sales next door, would support, and how few of those owners ever appeal.
The screening system is ours, and so is every case. We read the county record for your parcel, build the evidence, file the petition, and follow it through the Board. There is no call center and no hand-off.
What we’re good at is reading the public record and presenting it the way the Board weighs it. We don’t put our own number on your home, and we don’t promise an outcome. Our mailing address is our registered office in Spokane; the work happens here in King County.
Why use us instead of doing it yourself?
You can file your own appeal for free, and some people do. Most don’t, because it means building evidence against a hard deadline. What we’re best at is knowing which cases are worth filing, and we only bring you the ones the record supports.
About the risk of an increase
A Board of Equalization can raise an assessment as well as lower it, if the evidence shows it’s below market value. It’s uncommon, but it happens. We only file cases the evidence supports, and no outcome is guaranteed. If a closer look changes our view of your case, we’ll tell you before anything is filed.
Apartments and commercial property
Own an apartment building or commercial property?
We handle those appeals too. The Assessor values most apartment and commercial buildings on the income they can produce, not on nearby home sales, so the case is built differently: the county’s own rent, vacancy and expense assumptions set against what your building actually earns. Any rent or expense figures you share with us are kept confidential and used only for your appeal.
If you own one in King County, email hello@rainierpropertytax.com or call (206) 705-3246 with the address, and we’ll take a look. As with homes, there’s nothing upfront, and if the assessment doesn’t come down, you owe us nothing.
Common questions
Is this legitimate?
Are you affiliated with King County or the Assessor?
No. Rainier Property Tax Advisors is a private, independent Washington firm. We represent property owners, not the county, before the Board of Equalization. Washington law lets a property owner appoint an agent to handle a valuation appeal, and that’s the role we play for you.
Why you instead of a national service?
We only work in King County, so every case is built around how this Board decides.
How did you know my assessment might be too high?
County assessments and property sales are public record. We analyze that data to find properties whose assessed value looks out of step with their own recent sale or with what comparable homes are actually selling for. If yours is one of them, that’s why you heard from us. We don’t buy private financial data about anyone; here’s exactly what we use.
What do I actually have to do?
Confirm a few details, sign a short agreement and the county’s authorization, and put a card on file. From there we handle everything through the Board’s decision. In most cases you won’t need to attend anything, and nothing is charged unless your assessment comes down.
When do I pay, and how much?
Only after the Board reduces your assessment and the Assessor posts the new value to the roll. Our fee is 25% of your first-year tax savings. No reduction, no fee, and there are no upfront or filing costs either way.
Is there a deadline?
Yes, and it matters. A King County petition must be filed by the later of July 1 or 60 days from the mailing date printed on your value notice. Your letter from us shows the date for your parcel, and so does the county’s eAppeals site. Reach out at least a week before it so we have time to file.
Get started
Find out if your assessment is too high. It’s free.
Send us your property address or parcel number and we’ll review your assessment at no cost. If we don’t think you have a case, we’ll tell you.
Reach us
Prefer we start the review? Include your property address or 10-digit parcel number and we’ll take it from there.
What we’ll need
That’s enough for us to pull your assessment and comparable sales and tell you whether an appeal is worth filing.