Washington WAC Claims Rules: Diminished Value Evidence and Insurer Responses
The Washington Administrative Code sets standards for insurance claim handling. It does not award a fixed diminished value amount for every collision.
WAC 284-30-330: fair settlement practices
Read the current rule. Relevant subjects include misrepresentation, investigation, explanations for denial and reasonable handling. A disagreement about an appraised dollar amount is not automatically proof of a regulatory violation.
WAC 284-30-370: investigation
Read the current rule. Preserve your initial claim notice, document requests and responses. The October 18, 2026 amendments change portions of the rule, including written explanation requirements; check the version applicable to the claim.
WAC 284-30-380: settlement standards
Read the current rule. Distinguish first-party deadlines from third-party negotiations and avoid quoting timing provisions without their applicability and effective date.
WAC 284-30-390: motor-vehicle claims
Read the current rule and identify the specific subsection before relying on it. Do not cite the entire section as proof of a specific diminished value dollar amount.
WAC 284-30-391: a different subject
This rule concerns total-loss settlement methods. It is not a statutory post-repair diminished value calculator.
How to document an insurer dispute
- Save the policy, claim number and relevant dates.
- Keep the full estimate, supplements, photographs and independent report.
- Ask the insurer to identify the evidence and reasoning behind its response.
- Separate disagreement over value from allegations about claim handling.
- Use the Office of the Insurance Commissioner for official guidance.
Washington primary sources and important limits
Washington’s insurance commissioner explains that diminished value generally concerns the market-value difference remaining after repair and that it is usually pursued against the at-fault driver’s insurer. It is not paid automatically: the loss must be supported by evidence. Read the OIC’s auto-claim guidance.
WAC 284-30-330 addresses unfair claim settlement practices; WAC 284-30-370 addresses investigations; WAC 284-30-380 addresses settlement standards. These rules do not supply a universal diminished-value formula or guarantee payment. The OIC adopted revisions effective October 18, 2026; read the version effective for your claim.
RCW 48.18.620 governs appraisal provisions in qualifying first-party automobile physical-damage policies issued or renewed effective January 1, 2026 or later. Whether a specific post-repair diminished-value dispute is within a policy’s appraisal scope requires policy and claim analysis. Do not assume this statute gives every third-party diminished-value claimant an appraisal right. WAC 284-30-391 addresses total-loss settlement methodology, not a post-repair diminished-value formula.