Who this is for
Informational — owners and buyers estimating carrying costs and comparing cities.
Key takeaways
- Effective rates across most King County cities land roughly between 0.75% and 1.05% of assessed value.
- Your bill is assessed value times the combined levy rate — school levies are usually the largest component.
- A rising assessment does not automatically mean a proportionally higher bill.
- Assessment appeals have a firm deadline and require comparable sales evidence.
How the calculation actually works
Two inputs. The King County Assessor sets your property's assessed value as of January 1 each year. Separately, the taxing districts you sit in — school, city, county, fire, library, EMS and voter-approved levies — combine into a total levy rate expressed per $1,000 of assessed value.
Multiply the two and you have your bill. This is why two identical houses in different cities can pay materially different amounts: the assessed values may match, but the levy stacks do not.
| 城市 | Typical effective rate | Notes |
|---|---|---|
| 贝尔维尤（Bellevue） | ~0.78% | High values, comparatively moderate rate |
| 西雅图 | ~0.92% | Multiple voter-approved levies |
| 柯克兰（Kirkland） | ~0.85% | Lake Washington SD levies |
| 雷德蒙德 | ~0.88% | Lake Washington SD levies |
| 萨马米什（Sammamish） | ~0.84% | Newer stock, high assessed values |
| 伦顿 | ~1.02% | Lower values, higher combined rate |
Why a higher assessment isn't always a higher bill
Washington limits how much most regular levies can grow year over year, which means when assessed values across a district rise broadly, the levy rate generally falls to compensate. Your bill moves meaningfully only when your property's value rises faster than your neighbours' — or when voters approve a new levy.
This is the single most misunderstood part of the system. Getting an assessment notice showing a big increase is not, by itself, a reason to panic or to appeal.
How to appeal an assessment
Appeals go to the King County Board of Equalization, and the filing window closes shortly after assessment notices are mailed — typically within sixty days. Miss it and you wait a year, so calendar it the day your notice arrives.
A successful appeal is built on evidence, not opinion: comparable sales near the January 1 valuation date, documentation of condition issues the assessor could not see, and correction of any factual errors in the property record such as square footage or bedroom count. We prepare comparable packages for clients at no charge; it is a straightforward exercise with real financial upside.
- Diarise the appeal deadline the day the notice arrives.
- Pull comparable sales close to the January 1 valuation date.
- Check the property record for factual errors — they are common.
- Document condition issues with photographs and contractor estimates.
Exemptions worth checking
King County operates a senior citizen and disabled persons exemption program with income thresholds that have been raised in recent years, and a separate deferral program. Many eligible owners never apply simply because they assume they earn too much. It is worth ten minutes to check the current threshold.
For investors, property tax is deductible against rental income, and the timing of payment can matter for your tax year. Coordinate with your CPA — we do not provide tax advice, and this article is general information rather than guidance on your situation.
A note for international owners
Property tax is separate from the withholding that applies when a foreign person sells U.S. real property. FIRPTA is a withholding mechanism, not a tax in itself: a percentage of the gross sale price is withheld at closing and remitted, then reconciled against the seller's actual U.S. tax liability when a return is filed. Many sellers receive a substantial portion back.
Planning early matters. A withholding certificate application, filed before closing, can reduce the amount withheld when the expected liability is lower than the standard withholding. That is a conversation to have with a qualified U.S. tax advisor well before the listing goes live.
Frequently asked questions
What is the property tax rate in King County?+
Effective rates for typical residential parcels generally fall between roughly 0.75% and 1.05% of assessed value depending on city and levy stack. Bellevue sits near the lower end and Renton near the higher end.
Why did my King County property tax go up?+
Usually because your property's assessed value rose faster than the district average, or because voters approved a new levy. A broad increase in values alone typically causes levy rates to fall, offsetting much of the change.
How do I appeal my King County assessment?+
File with the King County Board of Equalization within the window stated on your assessment notice — typically sixty days. Support the appeal with comparable sales near the January 1 valuation date and documentation of any factual errors.
Is FIRPTA a tax on foreign sellers?+
No. FIRPTA is a withholding mechanism. A percentage of the gross sale price is withheld at closing and later reconciled against the seller's actual U.S. tax liability, and a withholding certificate filed before closing can reduce the amount withheld.
Maggie Sun, Managing Broker
Maggie leads a Bellevue-based bilingual real estate team, advising buyers, sellers and investors across Bellevue, Seattle and the Eastside in English and Mandarin. Market figures in this article are sourced from NWMLS and Redfin reporting for the periods noted, and are refreshed as new data publishes. This article is general information, not legal, tax or investment advice.
Ask Maggie about your situation