King County Property Taxes, Explained for Homeowners

Here is a number that confuses almost everyone who gets a King County tax statement. In 2026 the median Seattle home's assessed value fell 3.6%, from $864,000 to $833,000, and its property tax bill rose 3.9%, from $7,944 to $8,254. Values went down. Taxes went up. Nobody made a mistake, and once you understand why, most of what is puzzling about property tax in Washington stops being puzzling. This is the plain version: how the bill is actually set, where the money goes, when you can fight your assessment, when you have to pay, and the exemption that a lot of long-time owners qualify for and never claim.

How the Bill Is Actually Set

Washington runs a budget-based system, and that one fact explains nearly everything.

Your tax is not a rate applied to your home's value the way sales tax is a rate applied to a purchase. Instead, each taxing district, meaning the state, the county, the city, the school district, the fire and library and park districts, decides how many dollars it will collect next year. The county then divides that total by the assessed value of all the property in the district, and the result is the levy rate, expressed per $1,000 of value. Your bill is your assessed value times the sum of every district's rate where you live.

Read that again with your own house in mind. If every home in Seattle doubled in value overnight, the districts would still collect the same dollars, so the rate would halve and your bill would barely move. If your value rises faster than your neighbors' values, your share of the total grows. If it falls more slowly than theirs, your share grows too. Assessed value decides how the pie is cut. It does not decide how big the pie is.

What decides the size of the pie is two things. The first is the 1% limit: a district's regular levy can grow by no more than 1% a year over the prior year, plus whatever new construction adds to the tax base, regardless of what happened to values. The second is voters. Levies, lid lifts, and bonds approved at the ballot sit outside that 1% limit, and they are the reason bills rise faster than 1%. The county's own summary of 2026 says it directly: voter-approved measures, not rising values, are responsible for most of the increase.

What Happened in Seattle This Year

Put the pieces together and 2026 is a clean illustration.

The value fell because the market softened through 2025, which my monthly updates tracked. The rate rose because voters approved more spending. Seattle Public Schools passed a new six-year capital levy and a three-year technology levy, and Seattle renewed its Families, Education, Preschool and Promise levy at roughly double the previous rate. The school district's levy lines and the city's education levy together rose by more than $0.61 per $1,000. Other lines fell as values shifted, which is how the net increase came out to $0.35, but the direction was set at the ballot box.

Countywide the picture is the same at larger scale: total property taxes collected in King County rose 10% to $8.4 billion in 2026, while total assessed value rose 5.4%. The gap between those two numbers is voter-approved spending.

None of this is an argument for or against any levy. It is an explanation of the mechanism, so that when your bill arrives you look at the right thing. Your assessment is rarely the reason.

Where a Seattle Tax Dollar Goes

The rate breakdown on the county's report for Seattle sorts into four buckets.

Schools are the largest piece by a wide margin, and they are also the most variable, because school district levies come back to voters every few years. The city's share is heavy with lid lifts that voters renewed: housing, transportation, libraries, education. The county's regular levy, the piece that funds roads, courts, and public health, is a small slice at about 5% of the bill on its own.

For a buyer, the practical version is monthly. The median Seattle home's 2026 bill works out to about $688 a month. On the $920,000 house that was the citywide median sale in August, the tax at Seattle's rate is roughly $9,116 a year, or about $760 a month on top of the $5,918 in principal and interest my August market update calculated. It is the second-largest number in the payment and the one buyers most often forget to budget.

Your Assessed Value, and When You Can Fight It

The Assessor values every property in the county every year, at 100% of market value as of January 1, using sales from around that date. A physical inspection happens about once every six years; the annual updates in between are statistical. The value set as of January 1 of one year determines the tax bill you pay the following year, which is why a 2026 bill reflects the market of early 2025.

You will get a valuation notice in the mail, and this is the part to pay attention to, because the notices go out on a rolling schedule by area from roughly May into the fall rather than all at once. The deadline to appeal is the later of July 1 or 60 days from the mailing date printed on your notice. Miss it and the value stands for that year.

An appeal goes to the King County Board of Equalization, not the Assessor, and it can be filed online. The question the board decides is narrow: was the property worth what the Assessor said on January 1? So your evidence is comparable sales from around that date, plus anything about the house itself the county could not see from the street, such as a failing foundation or an unpermitted addition that was assumed finished. A good broker can pull the comparables for you, and I do this for clients when the notice looks off.

Two cautions. Winning an appeal lowers your share, not the total, so the savings are your value reduction times the rate, which on a $50,000 reduction in Seattle is about $495 a year. Worth doing when the number is wrong, not worth a fight over a few thousand dollars of value. And the assessment is not a home valuation. It is a mass appraisal built from statistics, and it can be wrong in either direction; my guide to what your Seattle home is worth explains why it should never be the number you list at.

The Calendar

• 01February: tax statements are mailed. The amount reflects the assessed value from the prior January and the levy rates set that winter.
• 02April 30: the first half is due. Interest and penalties on the unpaid balance start May 1.
• 03May through fall: valuation notices arrive by area, each starting its own 60-day appeal clock.
• 04July 1: the earliest possible appeal deadline, for notices mailed before early May.
• 05October 31: the second half is due.

If your mortgage includes an escrow account, your lender pays both halves from the money collected in your monthly payment and adjusts that payment once a year when the bill changes. That adjustment, rather than the bill itself, is how most homeowners actually experience a property tax increase.

The Senior and Disabled Exemption

This is the part of the system most worth knowing about and least used. Washington exempts qualifying homeowners from a large share of their property tax, and in King County the qualifying income is higher than many people assume.

You qualify if you were 61 or older by December 31 of the prior year, or you are unable to work because of a disability, or you are a veteran with a service-connected disability rating of 80% or more. You have to own the home and live in it at least nine months of the year, and your combined disposable income for the prior year, which includes Social Security, has to be $84,000 or less for 2026 taxes.

What you get depends on income, in three tiers: $72,001 to $84,000, $60,001 to $72,000, and $60,000 or less. At every tier the exemption removes the voter-approved levies and bonds that make up so much of a Seattle bill, and the county freezes your assessed value at the level when you first qualified, so later increases do not reach you. The lower two tiers also exempt part of the assessed value itself from the remaining regular levies.

The size of the first step alone is easy to see in the county's rate book. Seattle's 2026 levy rate is $9.90845 per $1,000. Its senior rate is $4.24803. On the median $833,000 home, that is about $3,539 a year instead of $8,254, a saving of roughly $4,700 before any value exemption at the lower tiers. If you are a long-time owner on a fixed income and you have never applied, this is likely the largest single thing you can do about your housing costs. The application is on the King County Assessor's website, and a separate deferral program, for household income up to $88,998, lets qualifying owners postpone the second-half payment, though a deferral accrues interest and becomes a lien that is repaid when the home sells.

Buying and Selling: What the Listing Does Not Tell You

Three things about property tax matter in a transaction, and none of them show up on a listing.

The tax figure on a listing is the seller's current bill, and it may not be yours. If the seller had the senior exemption, the bill you see could be less than half of what the county will charge you, because the exemption ends with the sale and the frozen value is released. If the house was substantially remodeled or is new construction, the current bill reflects the value before the work, and the next assessment will catch up. Budget from the assessed value times the current rate, not from the seller's statement. My first-time buyer guide covers the rest of what goes into a real monthly number.

At closing, the year's tax is prorated to the day between buyer and seller, and escrow settles it as a credit or debit on the statement. It is one of the smaller lines, and my guide to the cost of selling a house in Washington puts it next to the larger ones.

And if the house came to you through an estate, nothing about the tax changes at the transfer, but the exemption the previous owner may have held does not carry over to you. My guide to selling an inherited house in Washington covers what does and does not follow the property.

The Federal Deduction

Property tax is deductible on your federal return if you itemize, subject to the cap on state and local taxes. That cap was raised from $10,000 to $40,000 for 2025 and rises 1% a year through 2029, so it is $40,400 for 2026. It phases down for households with income above $500,000, to a floor of $10,000, and under current law the whole thing reverts to $10,000 in 2030. Since Washington has no income tax, property tax and sales tax are the only state and local taxes most homeowners here have to deduct, which makes the higher cap more useful in Seattle than in most places. I am a broker, not a tax advisor, so confirm what applies to you with a CPA.

The Bottom Line

King County property tax is set by budgets and ballots, then divided across values. Your assessment sets your share; what voters approve sets the total. That is why the median Seattle bill rose in 2026 while the median value fell, and it is why the right response to a higher bill is usually to look at the levy list, not the assessment.

Three actions are worth taking from this. Check the date on your valuation notice when it arrives, because the appeal window is 60 days and the value it sets is next year's bill. If you are 61 or older, or disabled, and your income is under $84,000, apply for the exemption. And if you are buying, build the monthly number from the assessed value and the current rate rather than the seller's statement. My free Buyer Guide walks through the full monthly cost of a Seattle home, or tell me the house you are looking at and I will run the real number, tax included.