RCW 24.36.120

If the association is organized without shares of stock, the articles shall state whether the voting power and the property rights and interest of each member are equal or unequal; and if unequal the general rule or rules applicable to all members by which the voting power and the property rights and interests, respectively, of each member may be and are determined and fixed; and shall also provide for the admission of new members who shall be entitled to vote and to share in the property of the association with the old members, in accordance with such general rule or rules.