King County Property Tax Records

King County property tax records cover more than 700,000 parcels across the most populous county in Washington. The King County Assessor maintains assessed values, parcel data, and exemption information, while the Treasury handles billing and collections. You can search records online through the eReal Property portal or the interactive Parcel Viewer, both of which give free public access to assessed values, tax history, sales data, and property characteristics without any login or fee.

King County Assessor's Office

The King County Department of Assessments is the primary office for property tax records in the county. It sets assessed values for all real and personal property, runs relief programs for seniors and disabled veterans, and publishes annual inspection area maps. General inquiries go to 206-296-7300. The office also handles public records requests for bulk data and historical assessment files.

The Assessor maintains several online tools: eReal Property for parcel reports, eSales for recent sales data, eMap for spatial viewing, and paperless eValuations for owners who opt in. These tools give the public direct access to the same data the office uses internally. You don't need an account to search basic parcel information, and most lookups are free.

The Assessor's page at kingcounty.gov provides links to each of these search tools, relief program applications, and the annual physical inspection schedule. It's the best starting point if you're not sure which tool to use.

The King County Assessor's office page includes information on how property values are determined, how to appeal an assessment, and how the senior and disabled exemption programs work.

The Assessor's site links directly to the eReal Property search, the eSales tool, and exemption program applications.

King County eReal Property Search

The main online tool for King County property tax records is the eReal Property portal. You search by parcel number, which King County also calls the property tax account number. Results show property characteristics, assessed values, tax information, year built, square footage, and other data pulled directly from the Assessor's records.

Before you access detailed records, the system asks you to acknowledge RCW 42.56.070(9), which prohibits using lists of individuals for commercial purposes. This is a standard requirement across Washington county portals. The Assessor also notes that data accuracy isn't guaranteed, and users should verify critical information through the office directly.

The eReal portal is the fastest way to pull a full parcel report. It's free, doesn't need an account, and the results are detailed enough for most research needs.

The eReal Property search is the primary tool for finding King County parcel and assessment data by tax account number.

The eReal portal returns a full parcel report including assessed value, tax history, and property characteristics.

King County Parcel Viewer and GIS Tools

If you prefer a map-based search, the King County Parcel Viewer lets you find parcels by address, parcel number, or by clicking directly on the map. Once you select a parcel, the viewer links to the eReal Property report and the Districts and Development Conditions report for that parcel. It's hosted by the King County GIS Center and integrated with the county's open data platform.

For bulk data needs, the King County GIS Open Data portal hosts over a thousand datasets including Real Property Tax Receivables, Personal Property Data, and Foreclosure Parcels. Data is available in CSV, JSON, XML, and RDF formats. The portal also provides API access for developers and researchers needing parcel geometry and assessment attributes.

The King County Parcel Viewer is an interactive mapping application for finding parcel information visually.

The Parcel Viewer links to the eReal Property report and Districts and Development Conditions report for any selected parcel.

Paying King County Property Taxes

King County property taxes are due in two installments each year. The first half is due April 30 and the second half is due October 31. The King County Treasury Operations page has a full guide to payment options, due dates, and what happens if taxes go unpaid.

You can pay online, by mail, or in person. The online payment portal at payment.kingcounty.gov accepts credit cards, debit cards, and electronic checks. Online payments carry a service fee charged by the third-party processor. Mail payments must be postmarked by the due date and sent to King County Treasury, 201 S. Jackson St., Suite 710, Seattle, WA 98104. In-person payments are accepted Monday through Friday, 8:30 a.m. to 4:30 p.m. at the Customer Service Center on the second floor of 201 S. Jackson Street. A drop box for check and money order payments sits on the corner of Second Avenue and South Jackson Street and is available outside of business hours.

The payment portal also lets you look up your tax statement or property value notice. It includes a link to eReal Property Search for users who don't have their parcel number handy.

Mobile homes and floating homes are taxed as personal property in King County unless they're associated with a real property account. Business assets fall under personal property tax rules as well.

The King County Treasury property tax page explains payment methods, due dates, and exemption deferral programs.

The Treasury page covers real property, personal property, mobile homes, and payment drop box locations.

Assessments, Exemptions, and Appeals

King County assessors value all properties at 100 percent of fair market value as required by state law under RCW 84.40. Values reflect market conditions as of January 1 of the assessment year. The Assessor publishes annual inspection area maps that show which neighborhoods are being physically reviewed that year.

The Assessor's Office runs property tax relief programs for seniors, disabled veterans, and persons with disabilities. Qualifying homeowners may be eligible for reduced assessed values or frozen values that limit how much their taxes can increase. These programs are administered under RCW 84.36. Applications are available through the Assessor's website or by calling 206-296-7300.

If you think your property value is wrong, you can appeal to the King County Board of Equalization. The appeal process starts with filing a petition with the Board. Deadlines are strict. For appeals beyond the Board level, the Washington State Board of Tax Appeals at bta.wa.gov handles further review.

Property tax foreclosure in King County is governed by RCW 84.64. Real property with taxes three or more years delinquent becomes subject to foreclosure proceedings. Delinquent taxes also accrue interest and penalties under RCW 84.56. Contact the Treasury for information on delinquent payment plans.

Cities in King County

King County includes Seattle and many other incorporated cities. Property tax records for all of them are maintained by the King County Assessor and are searchable through the eReal Property portal.

Nearby Counties

These counties border King County. Each has its own assessor and parcel search system.