Seattle property tax is calculated by multiplying your home’s assessed value, set each year by the King County Assessor, by a combined levy rate that typically falls between roughly $10 and $13 per $1,000 of assessed value. The King County Treasury collects the bill in two installments: the first half is due April 30 and the second half is due October 31. The exact rate shifts year to year with voter-approved levies, and the assessed value changes with the local market, so two homes of similar size on the same block can carry noticeably different bills.
How Your Bill Is Calculated
Washington law requires every property to be valued at 100 percent of its true and fair market value.1Washington State Legislature. RCW 84.40.030 – Manner of Assessment of Real and Personal Property The assessor updates that value annually. Your bill is then that value multiplied by a consolidated levy rate that bundles together taxes imposed by the state, King County, the City of Seattle, the school district, the Port of Seattle, and various special-purpose districts.
Washington’s constitution caps the regular (non-voted) combined property tax rate at $10 per $1,000 of assessed value.2Washington State Department of Revenue. Homeowner’s Guide to Property Tax – Section: The 1% Constitutional Limit Voter-approved special levies for schools, parks, transit, and housing stack on top of that cap, which is why the Seattle rate usually comes in above $10. State law also limits regular-levy revenue growth for any taxing district to 1 percent per year over the prior year’s collections, plus an adjustment for new construction, unless voters approve more.
A simple example: if the assessor values your home at $750,000 and the combined rate is $12.50 per $1,000, your annual tax is $9,375. Because values are reset every year, your bill can move even when the rate holds steady.
Payment Deadlines
King County mails tax statements in February, which gives you time to review the charges before anything is due. The bill is split into two installments:
- First half due April 303King County, Washington. Property Taxes
- Second half due October 313King County, Washington. Property Taxes
If a due date lands on a weekend or holiday, it shifts to the next business day. You can also pay the whole year with the April installment if you prefer to be done with it.
What Happens If You Pay Late
Penalties and interest start building the day after a deadline passes. For a late first-half payment, King County calculates monthly late charges against the full year’s tax amount, not just the half you missed. Second-half delinquencies accrue charges against the second-half amount. Interest keeps adding on each month the balance sits unpaid.
If taxes remain unpaid for three years, the county treasurer must begin issuing a certificate of delinquency, which starts a formal foreclosure process. The county prosecuting attorney then brings a court action to foreclose the tax lien. You can still redeem the property by paying all back taxes, interest, and costs up until the close of business the day before the sale.4Washington State Legislature. RCW 84.64 – Lien Foreclosure Properties with total delinquent taxes of $100 or less, excluding interest and penalties, are exempt from this foreclosure process. Foreclosure takes years, but the financial damage from penalties and interest is immediate, so catching up on a missed installment quickly matters.
Exemptions and Deferrals That Can Lower Your Bill
Several programs reduce or postpone what you owe. None apply automatically. You have to apply through the King County Assessor’s Office.
Senior Citizens and Disabled Persons
If you are 61 or older by December 31 of the filing year, or if you retired early because of a disability, you may qualify for an exemption on your primary residence.5Washington State Legislature. RCW 84.36.381 – Residences – Property Tax Exemptions A surviving spouse or domestic partner of someone who was receiving the exemption also qualifies if they are at least 57 and otherwise meet the rules.
Your combined household disposable income, after qualified deductions, must be $84,000 or less.6King County. Senior Exemption Portal How much relief you get depends on the income tier you fall into. At the lowest income levels, you are exempt from all regular property taxes on the greater of $60,000 or 60 percent of your home’s value. At the middle tier, the exemption covers the greater of $50,000 or 35 percent of value, up to $70,000. At the highest qualifying tier, you are exempt from voter-approved excess levies and certain additional state taxes but still pay regular levies on the full assessed value.5Washington State Legislature. RCW 84.36.381 – Residences – Property Tax Exemptions The home must be your primary residence, though a temporary absence for hospital or nursing home care will not automatically disqualify you.
Disabled Veterans
Veterans receiving VA disability compensation with a combined service-connected rating of 40 percent or higher, or a total disability rating for a service-connected condition, can apply for the same exemption program.5Washington State Legislature. RCW 84.36.381 – Residences – Property Tax Exemptions There is no age requirement for qualifying veterans. The same income thresholds and tiered benefits apply, and the home must be the veteran’s primary residence.
Property Tax Deferral
Homeowners who meet the senior or disabled exemption criteria but still cannot afford even the reduced bill can defer a portion of their taxes under a separate program.7Washington State Legislature. RCW 84.38 – Deferral of Special Assessments and Property Taxes The deferred amount is not forgiven. It becomes a lien on the property that grows at 5 percent interest per year8Washington State Legislature. RCW 84.38.100 – Lien of Deferred Special Assessments and Property Taxes and can reach as much as 80 percent of your equity. When the property is sold or transferred, or when you permanently move out, the full deferred balance plus interest comes due. It keeps you in your home. It is closer to a slow loan against your equity than a tax break.
Home Improvement Exemption
If you remodel or add onto an owner-occupied single-family home, you can apply for a three-year exemption on the increased value from the work. The exemption covers up to 30 percent of the original structure’s value, which blunts an immediate tax spike while the improvements settle into the assessment.9North Bend, WA. Home Improvement Tax Exemption Program To be eligible, the home must not have received this same exemption within the past five years. The authority is RCW 84.36.400, and you apply through the King County Assessor’s Office.
Appealing Your Assessed Value
If you think the assessor’s value on your home is too high, you can challenge it before the King County Board of Equalization. An appeal is worth filing when recent comparable sales in your neighborhood support a lower figure, when the assessor’s record contains incorrect property details such as wrong square footage or lot size, or when physical problems with the home reduce its market value.
File by July 1 of the assessment year, or within 60 days of the mailing date printed on your valuation notice, whichever is later.10Washington State Legislature. RCW 84.40.038 – Petition to County Board of Equalization You can file online through King County’s eAppeals system or mail a petition form to the Board of Equalization in downtown Seattle.11King County, Washington. How to Appeal Your Valuation The board can waive a missed deadline for good cause, such as serious illness, a natural disaster, or a postal failure, but treat the deadline as firm.
Bring evidence. The strongest appeals include recent comparable sales from the same neighborhood, photos of physical problems with the property, and any independent appraisals. The burden is on you to show the assessor’s figure is wrong. If the board rules against you, the next step is the Washington State Board of Tax Appeals.
How to Pay
King County accepts several payment methods, each with its own cost:
- eCheck through the King County Treasury website pulls directly from your checking account. The convenience fee is $0.55 per transaction.12King County, Washington. Property Tax Payment Information
- Credit card payments (Visa, Mastercard, American Express, Discover) carry a fee of 2.35 percent of the charge, with a $2.00 minimum. On a $5,000 installment, that comes to about $117.50 in fees.12King County, Washington. Property Tax Payment Information
- Mailed checks go to King County Treasury with your parcel number written on them. The envelope must be postmarked by the deadline to count as on time.
- Drop boxes at the King County Administration Building in downtown Seattle accept in-person payments.
Most homeowners with a mortgage never deal with this directly. The lender collects an escrow amount each month and pays the tax on your behalf. When your assessed value jumps, expect the escrow portion of your mortgage payment to be adjusted the following year to catch up.