How to Pay Your King County Property Tax Bill
Where to send your King County property tax payment
King County Property Tax collects property taxes for King County, Washington. You can pay your bill online, by mail, in person, or by phone. The fastest route is the online payment portal at kingcounty.gov/depts/assessor, where you can pay immediately with a bank account or card. Payments made online before 5 p.m. on the due date are considered on time.
If you prefer to mail a check, send it to the address printed on your tax bill. Include your parcel number and the stub from your bill so the county knows which property the payment covers. Mail payments take 7 to 10 days to reach the county, so send them well before the due date to avoid a late fee.
You can also pay in person at the King County Assessor's office in Seattle during business hours, or by phone at the number listed on your bill. Phone payments are processed the same day if you call before the office closes.
Key Takeaways
- King County property tax bills are due in two installments per year, and the due dates are printed on your bill.
- Online payment through the county website is the fastest method and shows as received immediately.
- Late payments trigger a penalty equal to a percentage of the unpaid tax, and the rate increases if the bill remains unpaid for several months.
- If you cannot pay the full amount by the due date, contact the county to ask about payment plans or deferrals before the bill becomes delinquent.
- Property tax bills are mailed to the address on file with the county assessor, so update your address if you move.
Understanding your King County property tax bill
Your property tax bill shows the assessed value of your property, the tax rate set by King County and local districts, and the amount you owe. The bill is divided into two installments: the first half is usually due in April, and the second half is due in October. The exact dates are printed on your bill and also posted on the King County Assessor's website.
The assessed value on your bill is not the same as the market value of your home. King County reassesses property values each year, and the assessed value is used to calculate your tax. If you believe your assessed value is wrong, you can file a complaint with the county assessor's office, but this must be done before a deadline that varies by year.
Your bill also shows which taxing districts receive a portion of your payment — the county, your city, the school district, and any special districts like fire or library districts. Each district sets its own tax rate, and all of these rates combined determine your total bill.
What happens if you pay late
If your payment is not received by the due date, King County adds a penalty to your bill. The penalty is a percentage of the unpaid tax amount. If the bill remains unpaid for several months, the penalty increases and interest begins to accrue on the unpaid balance.
After a bill is unpaid for a certain period, the county may file a lien against your property. A lien means the county has a legal claim on your home until the tax debt is paid. This lien can affect your ability to sell or refinance your home, and it will appear on your credit report.
If taxes remain unpaid for several years, the county may foreclose on the property and sell it to recover the tax debt. This is a lengthy process, but it is a real consequence of ignoring property tax bills.
Payment plans and tax deferrals
If you cannot pay your full bill by the due date, contact King County before the bill becomes delinquent. The county offers payment plans that allow you to spread the cost over several months. You will still owe a penalty for the late payment, but a plan prevents the bill from going into foreclosure status.
King County also offers a property tax deferral program for homeowners who meet income and age requirements. If you are 61 or older, or if you are disabled or have a surviving spouse or child, you may be able to defer your property taxes. Deferred taxes are not forgiven — they become due when you sell the home or when the deferral ends — but the program gives you time to stay in your home without losing it to foreclosure.
To explore a payment plan or deferral, contact the King County Assessor's office directly. The staff can explain which options fit your situation and walk you through the process.
How ACH and online payments work
When you pay online through the county website, you enter your bank account number or card information. The payment is processed through the Automated Clearing House (ACH) system, which is a network that moves money between banks. ACH payments typically take one business day to clear, but the county's system usually shows your payment as received immediately.
If you pay by card, the county may charge a processing fee — this fee is added to your payment total and goes to the payment processor, not to the county. The fee varies depending on the card type. If you pay by bank account (ACH), there is usually no fee.
Online payments are recorded in the county's system right away, so you have proof of payment immediately. Keep your confirmation number for your records. If you ever need to dispute a payment or prove you paid on time, the confirmation number is your evidence.
Updating your mailing address and account information
Property tax bills are mailed to the address on file with the King County Assessor. If you move, update your address with the assessor so your bills reach you. You can update your address online through the county website or by calling the assessor's office.
If you own the property but do not live there — for example, if you own a rental or a vacant lot — make sure the assessor has a current mailing address for you. Bills sent to an old address may not reach you, and you could miss the due date without knowing it.
You can also set up email notifications through the county website so you receive a reminder when your bill is ready. This is a free service and helps you stay on top of due dates.
Frequently Asked Questions
What if I did not receive my property tax bill?
Contact the King County Assessor's office and provide your parcel number. The office can tell you whether a bill was mailed and to what address. If the bill was sent to an old address, update your information immediately. You are still responsible for paying by the due date even if you did not receive the bill.
Can I pay my property tax bill through my bank's bill pay service?
Yes, many banks allow you to set up bill pay to King County. Check with your bank to confirm they support payments to the King County Assessor. Make sure you include your parcel number on the check so the payment is credited to the correct property.
What is the difference between assessed value and market value?
Assessed value is what the county estimates your property is worth for tax purposes. Market value is what your home would actually sell for. The assessed value is usually lower than market value and is used only to calculate your tax bill. You cannot change your market value, but you can challenge your assessed value if you believe it is wrong.
Do I have to pay property taxes if I am on a fixed income?
You still owe property taxes, but King County offers a deferral program for seniors and disabled homeowners. The program allows you to postpone payment, though the taxes become due when you sell the home. Contact the assessor's office to learn whether you meet the requirements.
What happens if I pay one installment but not the other?
Each installment is treated separately. If you pay the first half but not the second half, the second half becomes delinquent and penalties apply to that portion only. Pay both installments by their due dates to avoid penalties on either bill.