The King County Board of Equalization publishes its statistics publicly: approximately 25% of the property values that reach a Board hearing result in some type of reduction. That means three out of every four homeowners who go through a hearing — file the paperwork, wait for it, take time off to attend — walk away with no change.
Part of this is by design: King County uses a standardized mass-appraisal model. Not every home comes out of that model over-assessed. Beyond that, some mistakes are preventable — the reasons below.
Reason 1: The Assessor is presumed correct
Washington State law places the burden of proof entirely on the homeowner. The Board does not approach your hearing as a neutral arbiter — it starts from the position that the Assessor's value is correct. You must prove otherwise with evidence.
Many homeowners walk into a hearing with a general sense that their taxes are too high, without the specific, market-based evidence needed to overcome that presumption. The Board cannot rule in your favor based on feeling.
Reason 2: Weak or irrelevant comparables
The most common evidence problem is comparables that are too old, too different, or too far away — and not adjusted to compensate. No two properties are identical, so every comparable's sale price needs to be adjusted for its differences from your home before it can be used to derive your home's market value. Skip that step, and even a strong comp doesn't establish anything. The Board will note the weaknesses and give the Assessor the benefit of the doubt.
Reason 3: The assessment was actually correct
Not every home is over-assessed. King County values residential property using mass appraisal — a statistical model applied across many homes at once, not an individual appraisal of your specific property. Like any statistical model, it doesn't land on the exact right number for every home: some properties come out fairly assessed, some under-assessed, some over-assessed, just from how the model generalizes across a neighborhood. That's exactly why King County allows appeals in the first place — to let homeowners correct the model's output when it lands wrong for their specific property.
What the 25% who succeed do differently
- They back up their case with specific, market-based evidence
- They bring comparable sales that are properly adjusted for how each one differs from their home
- They verify their home is actually one the mass-appraisal model got wrong before they ever file
The honest evaluation problem
Services with a financial incentive to file tend to encourage filing regardless. Homeowners rarely get an honest answer to the first question: do I actually have a case?
Mass appraisal produces some fairly assessed and some under-assessed homes along with the over-assessed ones, so a real evaluation should sometimes say no. A tool that always says yes isn't telling you anything about your specific case. A preliminary evaluation that gives you a straight answer — yes, the evidence supports an appeal, or no, it does not — saves homeowners the time and effort of a case that was never going to work, and fewer weak cases clogging the hearing queue benefits the Board too. That alone would prevent some of the failed 75%.
Appealo runs the comparable analysis before you commit to anything. We only recommend filing when we believe the evidence is strong enough to win. If the numbers do not support your case, we tell you clearly — the evaluation is free either way.
Is your home over-assessed?
Enter your King County home address and we will analyze your assessment against recent comparable sales in your neighborhood. The evaluation is free, the answer is honest, and if you have a strong case, we file within 2 business days of you signing, as long as your deadline is at least 2 business days away.