Mercer Island property tax, by the numbers
Most over-appraised neighborhoods in Mercer Island
Plat boundaries from King County's recorded subdivision maps. Limited to plats with at least 30 homes, ranked by the share of homes appraised at least 10% above what recent comparable sales support. Bar length is shown relative to the most over-appraised plat in Mercer Island.
What Mercer Island homes look like on the County's records
Year built
Building grade
Median finished area: 3,100 square feet.
What Mercer Island homeowners ask
When does King County mail valuation notices for Mercer Island?
Notices go out in waves between June and November each year, neighborhood by neighborhood. The deadline to file an appeal is July 1, or 60 days after the mailing date printed on your notice, whichever is later. Earlier filers tend to get earlier hearing dates.
How is my Mercer Island home's assessed value set?
King County values every parcel using mass appraisal: a model that estimates each home's value from recent sales of similar homes nearby. The model works at the population level; most homes land within a reasonable range. It works less well at the individual level, because it can't see the specific things that make your home different from the average. Individual valuations miss the mark in both directions, and a meaningful share are off enough to make appealing worthwhile.
What's the typical reduction when a Mercer Island appeal wins?
Successful appeals typically knock 5% to 15% off the assessed value. On a typical Mercer Island home (median assessed value $2,258,500), a 10% reduction works out to roughly $2,350 per year in lower property taxes. The reduction stays on the books until the next county-wide revaluation, so the savings stack up year over year.
Where does the data on this page come from?
Every number on this page comes from King County's own public records: parcel attributes, every arms-length sale the County has logged, and recorded building characteristics. It's the same source data the County itself uses to set the values it's defending.
Run yours.
Free thirty-second check against every recent comparable sale near your address. The typical recommended Mercer Island home is paying $2,161 a year more than it should. Yours could be more, could be less, could be zero.
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