How to Read Your Property Tax Assessment Notice
By Danielle Cui · March 19, 2026
Every property tax appeal starts with one piece of mail: your assessment notice (or the assessed value on your tax bill). It usually arrives in summer — in California around July, in King County, WA when values are set. Here's how to read it.
The numbers that matter
- Assessed (or total) value — the figure your tax is calculated from, and the number you'd be appealing. Compare it to your home's market value.
- Land value + improvement value — the assessed value split between the lot and the structure. They should sum to the total; an oddly high improvement value can signal a record error.
- Property characteristics — square footage, bedrooms, bathrooms, year built, lot size. Check these carefully — a wrong sqft or bed/bath count inflates your assessment and is an easy basis for appeal.
- Valuation / lien date — almost always January 1. Your comparable sales must cluster around this date.
- Appeal deadline — the date or window to file. This is the one to circle. (California: ~July 2–September 15; King County, WA: July 1 or 60 days from the notice, whichever is later.) (More on deadlines.)
What to do with it
- Sanity-check the characteristics. Wrong details? That alone can justify an appeal.
- Compare assessed value to market value using recent comparable sales near January 1.
- Note the deadline and don't let it pass.
If there's a clear gap between your assessed value and what comparable homes are selling for, you likely have a case. The next step is gathering the comps — which CompFinder does for you from your address.
Frequently asked questions
When do property tax assessment notices come out?
Typically in summer — in California around July, and in King County, WA when annual values are set and value-change notices are mailed. The notice (or your tax bill) shows the assessed value you'd appeal.
What is the valuation date on my assessment notice?
It's almost always January 1 of the tax year. Your comparable sales evidence should cluster around that date.
What should I check first on my assessment notice?
Verify the property characteristics — square footage, bedrooms, bathrooms, year built, and lot size. Errors there inflate your assessment and are a straightforward basis for an appeal.