King County posted new 2027 assessed values for most of Seattle this month. I loaded them into PADS and re-scored every single-family home in the city against its comparable sales. Here's what the county's own data shows.
The numbers
- 164,287 Seattle single-family homes analyzed.
- 162,052 of them, 98.6% of the city, are now on 2027 values.
- 29,100 come back flagged as over-assessed in our scoring. 29,100 of 164,287 is 17.7%.
For comparison, the county-wide flag rate is 14.9%: 75,671 flagged homes out of 507,275 analyzed. Seattle runs above that.
Seattle moved the wrong direction
A revaluation cuts both ways. It fixes some over-assessments and creates new ones. Across the county the fixes won: 14,255 homes that looked over-assessed before the reval were resolved by their new values, while 10,594 homes picked up a new flag.
Seattle was the exception. It was the only major city in the county where new flags outnumbered fixes, a net of 802 more over-assessed homes than before the reval. If your Seattle assessment looked fine last year, that's not a guarantee it still does.
Your appeal window
The deadline to appeal is July 1 of the assessment year, or 60 days after the date your value change notice was mailed, whichever is later. The date that matters is the mailing date printed on the notice, not the day it reached your mailbox. New-value notices are going out now, so for most Seattle owners the 60-day clock is already running or about to start. Once it lapses, you're locked into the value until next year.
What a flag means, honestly
A flag is not a promise. It means your assessed value sits above what recent comparable arms-length sales near you support, by enough that filing is worth considering. The Board of Equalization's own records for 2021 through 2024 show 21.9% of petitions ended in a reduction: about 1 in 5, across 15,630 petitions. Most people who file lose. The homes we flag file with better evidence than average, but nobody should tell you a win is certain.
The other direction matters too. Most Seattle homes come back fair in our scoring. If yours does, I'll say so, and my advice is simple: don't appeal.
The honest caveat
Not every Seattle home is on new values yet. 98.6% are; the rest are still assessed on their 2026 values while the county finishes its geographic waves. County-wide, 82% of the homes we analyze are on 2027 values so far. If your notice hasn't arrived, any verdict you see today is scored against your 2026 value and can change when the new one lands. Check the tax year shown on your lookup before you act on it.
Every number above comes from King County's public assessment rolls and the Board of Equalization's published hearing records. I don't have private data. I just read the public data closely.