The one-sentence version
The tax you pay in 2026 is based on what your property was worth on January 1, 2025 — multiplied by levy rates the taxing districts set in late 2025, and collected this year. The value year is always one year behind the collection year.
The full sequence
Your assessed value and your final bill are set at different times by different offices. That is why you can know your value for months but not your real bill until January.
January 1, 2025
Valuation date. Your property's worth is fixed as of this day. That figure — your assessed value — is what your 2026 tax is built on.
During 2025
The Assessor sets that value. You have a window that year to review or appeal it.
Fall 2025
The taxing districts (schools, fire, library, county, and others) set their budgets.
By the first Monday in December 2025
Districts certify their levy amounts to the Assessor. The Assessor then calculates the rates.
January 2026
The Assessor certifies the final tax roll to the Treasurer. This is the point your actual dollar amount becomes official.
On or after February 15, 2026
Collection begins — the Treasurer cannot collect before February 15.
April 30, 2026
First half due.
October 31, 2026
Second half due.
The correct formula
The common error to avoid: labeling the value as the current tax year, or pairing a current-year value with a current-year rate. The value year is always one year behind the collection year.
The statutory anchors
For anyone who wants to verify it in the law:
- Valuation date — January 1 of the assessment year. RCW 84.40.020
- Districts certify levy amounts to the Assessor by the first Monday in December. RCW 84.52.020 · 84.52.070
- Assessor certifies and delivers the tax roll to the Treasurer (typically mid- to late January). RCW 84.52.080
- Treasurer cannot collect before February 15. RCW 84.56.010
- First half due April 30, second half due October 31. RCW 84.56.020
Voter-education resource. This explainer is produced by Rick Viall's campaign for Chelan County Treasurer. It is general information, not legal or tax advice, and is not a product of the Chelan County Treasurer's or Assessor's office. For your official figures, contact the Chelan County Treasurer's Office.