Wash. Rev. Code § 84.41.010
Recent comprehensive studies by the legislative council have disclosed gross inequality and nonuniformity in valuation of real property for tax purposes throughout the state. Serious nonuniformity in valuations exists both between similar property within the various taxing districts and between general levels of valuation of the various counties. Such nonuniformity results in inequality in taxation contrary to standards of fairness and uniformity required and established by the Constitution and is of such flagrant and widespread occurrence as to constitute a grave emergency adversely affecting state and local government and the welfare of all the people.
Traditional public policy of the state has vested large measure of control in matters of property valuation in county government, and the state hereby declares its purpose to continue such policy. However, present statutes and practices thereunder have failed to achieve the measure of uniformity required by the Constitution; the resultant widespread inequality and nonuniformity in valuation of property can and should no longer be tolerated. It thus becomes necessary to require general revaluation of property throughout the state.
RCW 84.41.010