Washington state constitution
Article VII
Section 11

Nothing in this Article VII as amended shall prevent the legislature from providing, subject to such conditions as it may enact, that the true and fair value in money (a) of farms, agricultural lands, standing timber and timberlands, and (b) of other open space lands which are used for recreation or for enjoyment of their scenic or natural beauty shall be based on the use to which such property is currently applied, and such values shall be used in computing the assessed valuation of such property in the same manner as the assessed valuation is computed for all property.