How to Appeal a King County Property Tax Valuation

Property Taxes Too High? How to Appeal Your King County Valuation (2025)

(Subtitle: A step-by-step appeal guide—and what your assessment means if you’re planning to sell in Seattle or Bellevue.)

Your King County property tax valuation notice just arrived. And it’s… higher than you expected. Maybe much higher. My own notice this year came in over $100,000 above my recent purchase price.

That number matters for taxes. But it also matters if you’re considering selling your home in Seattle, Bellevue, or anywhere in King County. Here’s why—and here’s how to challenge it if it’s wrong.

Tl;dr: File your appeal online via eAppeals by July 1 of the assessment year or within 60 days of your notice date. Build your case with January 1 comps, condition photos, and documentation.

Why Your Assessed Value Might Look Off

King County bases valuations on your property’s market value as of January 1 of the prior year. So, the amount you pay in taxes in 2026 is determined by the value of your home on January 1, 2025. In a fast-changing market like ours, the assessed number often lags actual home value. Sometimes it undershoots. Sometimes it overshoots wildly.

Assessed value ≠ sale price. But if you’re planning to list your home, an inflated number might spook buyers or cause confusion.

Appealing Your King County Property Tax Assessment

Step 1: Confirm Your Deadline

Appeals are due by July 1 of the assessment year or 60 days from your notice’s mailing date, whichever is later. Miss it and you’re out of luck until next year.

This official property value notice was delivered on 9/18/2025. The appeal is due in 60 days, no later than 11/17/2025.

Step 2: Gather Your Evidence

The King County Board of Equalization holds the power to adjust erroneous real estate tax assessments. But before they do, they’re going to want proof your number is wrong. That means you need to provide:

• Comparable sales: Homes like yours, as close to January 1 as possible.
• Home appraisals: If dated near January 1, these are gold.
• Proof of home condition: Photos + contractor bids showing deferred maintenance or needed repairs. In other words, if your home has some damage or deficiency that should reduce its value.
• Other factors: Easements, slopes, traffic noise, or anything that lowers market value.

Comparable homes should be similar in size, quality, and location.

Pro Tip: The closer your comps are to January 1, the stronger your case. Later sales require adjustments and won’t be taken as seriously.

Step 3: File Online with eAppeals

You can always appeal via mail, but to make life easier we strongly suggest filing online at King County eAppeals. There, you can enter your parcel, state your opinion of value, and upload supporting docs. Don’t skimp on the docs—these will make or break your appeal.

KC Assessor Appeals Landing Page

Step 4: Don’t Miss the Evidence Exchange

Both you and the Assessor must share any additional evidence with both the Board of Equalization and the Assessor at least 21 business days before your hearing. This deadline is strict.

• What to share: Comparable sales, appraisals, condition photos, contractor bids, maps, and a short cover page that clearly states your opinion of value.
• How to share: Upload to your eAppeals case and provide a copy to the Assessor’s Office. Don’t assume one office forwards your evidence to the other.
• Deadline basics: “Business days” exclude weekends and county holidays. Count backward from your hearing date to avoid last-minute surprises.

Tip: Organize your evidence clearly—label files and paginate your packet so the Board can follow your points easily.

Step 5: Present Your Case

You’ll receive a hearing notice in advance of your scheduled date. At the hearing, you’ll have the chance to present your evidence and explain why your assessed value is too high.

• Format: Hearings are relatively brief, a maximum of 40 minutes. You’ll present your case, the Assessor may respond, and Board members may ask questions.
• Focus on value: Keep your presentation tied to market value as of January 1. The Board will not consider arguments about the tax rate itself—only whether the value is correct.
• After the hearing: The Board issues a written decision within 45 days of the hearing. If your appeal is successful, your assessed value (and taxes) will be adjusted. If you disagree with the result, you can appeal further to the Washington State Board of Tax Appeals.

What This Means if You’re Selling

If you’re planning to sell in Seattle or Bellevue, appealing your valuation is just one piece of smart prep. The bigger question: what’s your home really worth in today’s market?

Even though an assessed value isn’t the same as market value, buyers often notice it when browsing listings or public records. If the county’s number is far higher than your asking price, some buyers may assume your home has hidden issues or wonder if the price is “too good to be true.” On the other hand, if you list close to that inflated assessment, your home may look overpriced compared to similar properties. By correcting the assessment—or at least showing that you appealed—you keep the focus where it belongs: real comparable sales and your true asking price.

If your assessed value is way below market, lucky you—your taxes stay low, and buyers will still pay today’s price. The only downside? Don’t expect the county to stay fooled forever.

How much do you think this Seattle North Beach home was assessed for? $1,629,000.

FAQs

Do I need an appraisal to win?

Not always. Strong comparable sales are often enough. Appraisals can help but aren’t mandatory.

Can I handle the hearing myself?

Yes. Most homeowners represent themselves. Bring clear evidence and stay on point.

Does appealing hurt my chances of selling?

No. In fact, it can help by clearing up confusion around value. Buyers appreciate transparency.

Ready to Talk Value?

If you’re a homeowner in Seattle, Bellevue, or greater King County and you’re wondering about your assessed value, odds are you’re also curious what your home might sell for—and what your next move could look like.

• We can prepare a custom market analysis that doubles as strong appeal evidence.
• We’ll show you how your assessed value compares to real buyer demand today.
• And if you’re thinking about selling, we’ll walk through what buyers care about (and what they don’t).

Want clarity on your home’s true market value—and a plan for what comes next? Contact us here.

About Ryan

Ryan attended law school at the University of Washington, obtained his WSBA license in 2018, and practiced law before joining Get Happy at Home. Now he helps Seattle-area homeowners evaluate, sell, and buy homes with sharp strategy and less stress.

LEGAL DISCLAIMER: The information in this post is for general informational purposes only and is not legal or tax advice. Always confirm procedures and deadlines with King County or a qualified attorney.