Mason County, WashingtonProperty records & tax offices
Links open the listed public-office or service-provider website in a new tab. This directory does not collect payments.
Find the right property record
Use the property portal for ownership and assessed value, the collector for a bill or balance, and the map for parcel location. Have the address, owner name, or parcel number ready.
Tax bills & filing dates
These are the dates and qualifications recorded in the directory. Confirm your tax year and current deadline with the official office and your property’s notice.
- Payment deadline
- April 30, 2026 for the first half or full payment; October 31, 2026 for the second half; payments postmarked by the due date are timely.
- Assessment appeal
- July 1, 2026 or within 30 calendar days after the Official Notice of Value was mailed, whichever is later; petition to the Mason County Board of Equalization.
Exemptions & appeals
Senior relief
Mason County administers the Washington senior/disabled property-tax exemption and deferral programs for qualifying owners of a primary residence. The official application requires age/disability, ownership, occupancy, and combined disposable-income documentation; contact the Assessor for the current county threshold and application cycle.
Valuation limits
Washington's constitutional 1% property-tax limit and the statutory 1% levy limit constrain taxing-district revenue, not an individual parcel's assessed value. County assessors value property at 100% of true and fair market value, so an individual assessed value can rise or fall by more or less than 1%; voter-approved excess levies, new construction, and senior/disabled relief are separate rules.
For a valuation appeal, use the appeal date in the tax and filing section above. Keep your notice, supporting evidence, and proof of submission.
More exemption & appeal guidance →