Washington has a provisional filing deadline of July 1st of the assessment year. However, for all value notices sent after June 1st, the deadline for filing is extended to 30 days from the postmarked date of the value notice.

To start an appeal, you will need to either file a Taxpayer Petition for Review of Property Valuation Determination form with the county where your property is located or appoint a tax consultancy such as Ownwell who can file on your behalf. Your appeal must be submitted using this form; letters or phone calls are not acceptable forms of submission in Washington. These forms are available online at the Washington Department of Revenue’s website, or at any local county board of equalization and assessor’s offices. All submitted appeal forms are required to be time-stamped before midnight of the deadline date.

In Washington, the burden of proof is on the property owner (or tax consultant working on their behalf). This means to win an appeal you must provide clear, cogent, and convincing evidence your property is overassessed. The County Board of Equalization requires an evidence packet that supports any value claims to be submitted as part of the appeal process. Some examples of acceptable evidence include: proof of a recent third party appraisal of the property, documentation of excessive deterioration or quotes for repairs required for the habitability of the property, and sales comparables for properties with similar characteristics that reflect a lower value. All information must be provided at least 21 business days before the hearing.