This bill amends RCW 84.48.150 and creates a new section to require county or local assessors, when a taxpayer petitions the board of equalization over a tax claim or valuation dispute, to provide on request a compilation of comparable sales used to establish that taxpayer’s valuation. If the assessor relied on valuation criteria other than comparable sales, the assessor must provide those factors and the addresses of properties used. The assessor must respond within 60 days of the taxpayer’s request and must provide the valuation criteria and/or comparable sales at least 28 business days (excluding legal holidays) before the taxpayer’s appearance before the board. The assessor may not change those items later unless new evidence supporting the assessor’s valuation is found, in which case the assessor must provide the additional evidence at least 28 business days before the hearing. The bill also establishes timing rules for taxpayers: a taxpayer who lists comparable sales on a notice of appeal may not later change those sales unless new evidence is found, and any additional evidence must be provided to the assessor and the board at least 21 business days (excluding legal holidays) before the hearing. If either party misses these timing requirements, the board of equalization may continue the hearing to allow review of all evidence or, upon objection, refuse to consider sales not submitted in a timely manner. The new rules apply to appeal petitions filed on or after July 1, 2026. The extracted text does not include formal statutory definitions of terms such as “assessor,” “taxpayer,” or “board of equalization,” nor does it show other parts of RCW 84.48.150 that may be affected.

If enacted, county and local assessors will need to assemble and send taxpayers the specific comparable sales or other valuation factors and the addresses used to set a property's value when the taxpayer asks during an appeal. Those materials must be delivered within 60 days of the request and at least 28 business days before the appeal hearing, and assessors generally cannot change them later unless they find new evidence and then must give that new evidence 28 business days before the hearing. Practically, assessors will likely need more staff time and record‑processing procedures to meet these deadlines, and missed timing could lead to postponed hearings or exclusion of evidence, creating scheduling risks and possible legal challenges. Taxpayers who list comparables on an appeal will have less flexibility to swap in different sales late in the process unless they find new evidence and then must share it with the assessor and board at least 21 business days before the hearing, which pushes taxpayers to prepare earlier. Boards of equalization gain clearer grounds to continue hearings or refuse untimely evidence. The change would take effect for appeals filed on or after July 1, 2026. Key details are unclear here, including formal definitions of terms like "board of equalization" and the rest of the amended statute, so exact implementation and which specific boards or offices are affected may still be uncertain.