Appeal guide · Washington
How to appeal a commercial assessment in King County
8 steps from the notice to the King County Board of Equalization and beyond, with the forms, exchange deadlines and mistakes that decide commercial cases here.
Deadline
Petition postmarked, hand delivered or filed online by the later of July 1 of the assessment year or 60 days after the mailing date printed on the value notice (King County's adopted limit under RCW 84.40.038)
Where to file
King County eAppeal online petition system, or the paper Real Property Petition filed by mail or in person in duplicate
Statute
RCW 84.40.038 (petition and deadline); RCW 84.48.010 (county board of equalization); WAC 458-14 (board practice rules)
The process, in order
Hearings are held by telephone before the Board, or the petitioner can choose an administrative review in which the Board decides on the written record. Scheduling commonly takes six months or more. After evidence and the Assessor's response are exchanged, a petitioner can ask for an expedited hearing. The Board issues a written order to both parties within 45 days after the hearing.
Forms you will need
- +Real Property Petition to the King County Board of Equalization
- +Agent authorization signed by the owner
- +Washington State Board of Tax Appeals Notice of Appeal
- 1
When the change of value notice arrives
Log the value notice date
Record the mailing date printed on the notice and calculate the later of July 1 or 60 days from that date. Each parcel in a portfolio can have a different deadline.
- 2
Before building the analysis
Read the area report
Pull the Assessor's commercial area report for the parcel's specialty and neighborhood, and note the rent, vacancy, expense and cap rate parameters applied to its class.
- 3
Within the filing window
Talk to the commercial appraiser
An informal review with the assigned appraiser can correct building area, class or vacancy errors without a hearing. Keep the deadline in view; informal talks do not extend it.
- 4
By the later of July 1 or 60 days from the notice
File the petition
File through eAppeal or on paper in duplicate, one petition per parcel, with specific reasons and the owner's agent authorization.
- 5
At least 21 business days before the hearing
Submit evidence
Send the income approach, rent roll, operating statements, leasing evidence and sales to both the Board and the Assessor. The Assessor's response is due on the same schedule.
- 6
Often six months or more after filing
Hearing or administrative review
Present by telephone or elect a decision on the record. After the evidence exchange, an expedited hearing can be requested by email.
- 7
Within 45 days after the hearing
Board order
If the value is reduced, the Treasurer issues a revised statement or a refund for taxes already paid.
- 8
Within 30 days of the order's mailing date
Board of Tax Appeals
File with the Washington State Board of Tax Appeals, choosing a formal or informal hearing. Expect the Assessor to file its own appeal on large reductions.
Mistakes that lose King County appeals
- Writing only that the value is too high, which makes the petition incomplete and leads to rejection.
- Mailing evidence fewer than 21 business days before the hearing; if the Assessor objects, it can be excluded.
- Arguing that the increase is too large or that neighboring assessments are lower, which the Board does not treat as evidence of market value.
- Missing a parcel's deadline because portfolio notices were mailed on different dates.
- Presenting actual income without tying it to the Assessor's published rent and vacancy parameters for the class.
Evidence rules
- 1.WAC 458-14-066: both the petitioner and the Assessor must provide valuation evidence at least 21 business days, excluding legal holidays, before the hearing; the postmark controls. If the other side objects to late evidence the Board may exclude it, postpone, or hold the record open.
- 2.WAC 458-14-056: a petition is complete only if every relevant question is answered with reasons specific enough to inform the Board and the Assessor; incomplete petitions are rejected by notice.
- 3.RCW 84.40.0301: the Assessor's value is presumed correct, and the petitioner must overcome it by clear, cogent and convincing evidence.
- 4.The Board does not consider percentage increases, the amount of tax, personal hardship, or comparisons of other properties' assessments as evidence of market value.
- 5.File a separate petition for each parcel, in duplicate if filing on paper.
Frequently asked
What is the King County appeal deadline?
The later of July 1 of the assessment year or 60 days after the mailing date printed on the value notice. Petitions must be postmarked, hand delivered or filed online by that date.
When does a 2026 reduction affect the tax bill?
Values are set as of January 1, 2026 for taxes payable in 2027. If the Board's decision comes after the bill is issued, the Treasurer issues a revised statement or a refund.
Can I appear in person?
Hearings are held by telephone, or the petitioner can choose an administrative review in which the Board decides on the written evidence without participation.
What burden does the owner carry?
The Assessor's value is presumed correct, and the petitioner must show it is wrong by clear, cogent and convincing evidence under RCW 84.40.0301.
File a stronger King County appeal this cycle.
ATALI ELECTRIC builds the income, sales and uniformity exhibits, fills the county forms and tracks every deadline.