Washington Revised Code Title 48. Insurance § 48.18.480. Discrimination prohibited

No insurer shall make or permit any unfair discrimination between insureds or subjects of insurance having substantially like insuring, risk, and exposure factors, and expense elements, in the terms or conditions of any insurance contract, or in the rate or amount of premium charged therefor, or in the benefits payable or in any other rights or privileges accruing thereunder. This provision shall not prohibit fair discrimination by a life insurer as between individuals having unequal expectation of life.