Washington Revised Code Title 64. Real Property and Conveyances § 64.28.040. Character of joint tenancy interests held by both spouses or both domestic partners

(1) Joint tenancy interests 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, the same as other property held in the name of both spouses or both domestic partners. Any such interest passes to the survivor of the spouse or survivor of the domestic partner as provided for property held in joint tenancy, but in all other respects the interest is treated as community property.

(2) Either person in a marriage or either person in a state registered domestic partnership, or both, may sever a joint tenancy. When a joint tenancy is severed, the property, or proceeds of the property, shall be presumed to be their community property, whether it is held in the name of either spouse, or both, or in the name of either domestic partner, or both.

(3) This section applies as of January 1, 1985, to all existing or subsequently created joint tenancies.