King County property tax is calculated by dividing your home’s assessed value by 1,000 and multiplying by the combined levy rate for your location, then billed in two installments due April 30 and October 31.1King County. City Tax Comparison for 2024-2025 The King County Assessor sets the value; King County Treasury Operations handles the billing and collection.
How Your Bill Is Calculated
The math is simple. A home assessed at $200,000 in an area with a combined levy rate of $13 per thousand produces a bill of $2,600 for the year.1King County. City Tax Comparison for 2024-2025 The combined levy rate is the sum of every taxing district that covers your parcel: school district, fire district, library system, port, transit authority, and others. Two homes with identical assessed values can owe very different amounts because they sit inside different combinations of districts.
The Assessor values every property at 100 percent of its true and fair market value as of January 1 each year, using recent comparable sales and any physical improvements.2Washington State Legislature. Washington Code 84.40.040 – Assessor to List All Real and Personal Property When the local market rises, your assessed value rises with it, and your bill goes up even if the levy rates hold steady.
Legal Caps on Levy Rates
Two separate limits restrain what districts can collect. The Washington State Constitution caps the combined regular rate on any single property at one percent of true and fair value, which comes out to $10 per $1,000 of assessed value. Voter-approved levies, such as school bonds, can lift the effective rate above that ceiling. Separately, state statute caps each taxing district’s total levy growth at one percent per year, plus whatever new construction adds, unless voters approve more.3Washington Department of Revenue. Property Tax – How The 1% Property Tax Levy Limit Works Most year-over-year movement in a King County bill comes from shifts in assessed value, not from the rates themselves.
When and How to Pay
The first half of your annual bill is due April 30, and the second half is due October 31. If your total annual tax is under $50, the full amount is due April 30.4Washington State Department of Revenue. Property Tax Calendar Due Dates One detail trips people up every year: miss April 30, and the entire year’s balance becomes delinquent at once, not just the first installment.
Three ways to pay:5King County. Property Tax Payment Information
- Online, with credit card (2.35% fee), debit card ($3.50 flat fee), or eCheck ($0.55).
- By mail, with a personal check and your tax account number on the memo line, sent to King County Treasury Operations, 201 South Jackson Street, Suite 710, Seattle, WA 98104. The postmark counts as the payment date.
- In person at the King County Customer Service Center, 201 South Jackson Street, Second Floor (East Lobby), Monday through Friday, 8:30 a.m. to 4:30 p.m. A secure drop box at the same location is available during business hours.
What Happens If You Pay Late
Interest runs at 12 percent per year, calculated monthly, on the entire delinquent balance from the delinquency date. On top of that, the county adds a 3 percent penalty on June 1 and an additional 8 percent penalty on December 1 of the year the tax is due.6Washington State Legislature. Washington Code 84.56.020 – Taxes Collected by Treasurer, Dates of Delinquency, Interest, Penalties A $5,000 bill left unpaid through the year can easily carry more than $1,000 in combined interest and penalties by January.
Once taxes have been unpaid for three years, the county treasurer must issue a certificate of delinquency and begin foreclosure.7Washington State Legislature. Washington Code 84.64.050 – Certificate of Delinquency, Foreclosure A court action follows, and if judgment is entered, the property is sold to the highest bidder for at least the total of taxes, interest, and costs owed. Owners are notified before the sale, but by that stage the debt has usually ballooned. Staying current, or arranging a deferral well before the three-year mark, costs far less than fighting a foreclosure.
Exemptions for Seniors, Disabled Residents, and Veterans
Washington offers a property tax exemption that can substantially cut your bill if you qualify. You must own and live in the home as your primary residence, and you must meet at least one of these conditions by December 31 of the filing year:8Washington Department of Revenue. Property Tax Exemption for Seniors, People Retired Due to Disability, and Veterans With Disabilities
- Age 61 or older.
- Age 57 or older and the surviving spouse or domestic partner of someone who held the exemption at death.
- Unable to work because of a disability, at any age.
- A disabled veteran with at least an 80 percent service-connected evaluation, or receiving VA compensation at the 100 percent rate.
Combined household income, after deducting qualified expenses, must be $84,000 or less for the 2024, 2025, and 2026 tax years.9King County. Senior Exemption Portal Household income includes earnings from your spouse, domestic partner, and any co-owners living in the home.10Washington State Legislature. Washington Code 84.36.381 – Exemptions, Residences of Persons Retired From Regular Gainful Employment Due to Age or Disability
Three Income Tiers
How much you save depends on where your income falls across three tiers, with the specific thresholds set each year at 70 percent of county median household income.11Washington State Department of Revenue. Property Tax Exemption for Senior Citizens and People With Disabilities
- Level 3, the highest-income tier, exempts you from voter-approved excess levies and Part 2 of the state school levy.
- Level 2 adds an exemption from regular levies on $50,000 or 35 percent of your assessed value, whichever is greater, capped at $70,000.
- Level 1 adds an exemption from regular levies on $60,000 or 60 percent of your assessed value, whichever is greater.
Applying
King County encourages applicants to use the online Senior Exemption Portal to file and upload documents.12King County. Senior or Disabled Exemptions and Deferrals A paper application is available if you prefer mail. Gather your federal tax return (if you file one), W-2 forms, and Social Security benefit statements for every household member.13King County. Senior Citizen and Disabled Persons Property Tax Exemption Application Instructions The Assessor’s office warns applicants not to email these documents for security reasons.
Deferral If You Still Can’t Pay
If you qualify for the senior or disabled exemption but can’t manage the remaining tax, Washington’s deferral program lets you postpone payment. Deferred taxes become a lien on the home and accrue five percent interest per year. The lien is allowed to grow up to 80 percent of your equity. Repayment comes due when the home is sold, you move out, or you pass away.14Washington Department of Revenue. Property Tax Exemptions and Deferrals It’s a real tradeoff. The program keeps seniors in their homes, but the accruing interest means the eventual payoff exceeds the original bills.
Appealing Your Assessed Value
If you think the Assessor’s figure overstates your home’s market value, you can petition the King County Board of Equalization. The deadline is July 1 of the assessment year, or 60 days from the date on your value change notice, whichever gives you more time.15Washington State Legislature. Washington Code 84.40.038 – Appeal to Board of Equalization You can file online or by mail to the Board at 516 Third Avenue, Room 1222, Seattle, WA 98104.16King County. How to Appeal a Property Tax Assessment
Your petition must include the parcel number, the Assessor’s listed value, your own opinion of value, and specific reasons the Assessor’s figure doesn’t reflect fair market value. Recent comparable sales, an independent appraisal, or documentation of defects strengthen a petition. Arguments based on the size of your tax bill, personal hardship, or how your increase compares to a neighbor’s will not be considered.16King County. How to Appeal a Property Tax Assessment
If You Own a Business
Property tax in King County reaches beyond real estate. Business owners must list all tangible personal property used in the business with the county assessor, including office furniture, computers, manufacturing equipment, construction machinery, signage, leasehold improvements, leased equipment, and fully depreciated assets still in use or storage. The listing must reflect everything owned or controlled as of noon on January 1, and the completed form is due by April 30.17Washington State Department of Revenue. Personal Property Tax The assessor values these assets and applies the local levy rate the same way as with real property, so missing the obligation means both unpaid tax and penalties.