Washington Revised Code Title 64. Real Property and Conveyances § 64.28.020. Interest in favor of two or more is interest in common--Exceptions for joint tenancies, partnerships, trustees, etc.--Presumption of community property

(1) Every interest created in favor of two or more persons in their own right is an interest in common, unless acquired by them in partnership, for partnership purposes, or unless declared in its creation to be a joint tenancy, as provided in RCW 64.28.010, or unless acquired by executors or trustees.

(2) Interests in common held in the names of both spouses or both domestic partners, whether or not in conjunction with others, are presumed to be their community property.

(3) Subsection (2) of this section applies as of June 9, 1988, to all existing or subsequently created interests in common.