Recent remodel sales, neighbors with lower values, deferred maintenance, or a double-digit jump while the market softened all point to overassessment.
Seattle homes are not all equal, but the Assessor's mass appraisal often treats them that way. The King County Assessor values more than 700,000 parcels from a desk, using sales models and aerial photos. Five patterns tend to show up when Fair Appeal pulls records on an overassessed home.
1. Your neighbors' identical homes carry lower assessed values
Pull up three homes on your street with the same square footage, lot size, and year built. If their assessed values sit 10% or more below yours, the Assessor has not treated your block consistently. Uniformity gaps are the cleanest assessment appeal argument available.
2. Your home backs onto an arterial, transit corridor, or commercial edge
Mass appraisal models weigh square footage and year built heavily. They miss what a human appraiser sees in 30 seconds: a bedroom window ten feet from Aurora, a back fence against a Link station, or a view of a warehouse roof. External obsolescence is routinely undervalued.
3. Your assessed value jumped 10% or more while the market softened
King County median home prices moved sideways through 2024 and into 2025, yet some neighborhoods saw double-digit assessment increases on the 2026 roll. If your value rose faster than your zip code's sale prices, the model is out of step with reality.
4. Nearby remodel sales pulled your value up
The Assessor's model uses recent sales to price your home, but it cannot always tell a down-to-studs remodel from a lived-in original. If three flipped homes sold on your block in 2024, your 2026 value may reflect their new kitchens rather than your 1978 one.
5. You have deferred maintenance the Assessor has not seen
Roof past its life, original single-pane windows, a foundation crack, rotted siding. None of this shows in aerial photos or permit records. If your home's physical condition is meaningfully worse than the model assumes, dated photos and repair estimates bring the assessed value down.
What to do next
Compare your property record card against three nearby homes on the King County Assessor site. If two or more signs apply, file a petition with the King County Board of Equalization by July 1, 2026, or within 60 days of your value notice. FairAppeal files King County appeals and only charges if the appeal wins. See the full 2026 King County deadline guide for filing details.