Tom Andrews, Cohabiting with Property in Washington: Washington's Committed Intimate Relationship Doctrine, 53 Gonz. L. Rev. 293 (2017), https://digitalcommons.law.uw.edu/faculty-articles/576
Gonzaga Law Review
Washington has followed a community property system since at least 1869—twenty years prior to statehood. However, Washington rejected the doctrine of common law marriage quite early in 1892. For over one hundred years, in order to receive the advantages of the community property laws, a Washington couple has needed to have their relationship blessed with a ceremonial marriage or have a valid common law marriage in another state.
Accompanying these requirements for the formal establishment of a community property regime was the so-called "Creasman Presumption," which provided that "property acquired by a man and a woman not married to each other, but living together as husband and wife, is not community property, and, in the absence of some trust relation, belongs to the one in whose name the legal title to the property stands." There were, nonetheless, some common law property work-arounds. Over the years, the Washington Supreme Court has identified a number of legal bases for dividing property that do not depend on legal title, including tracing, partnership, resulting and constructive trust, cotenancy, and contract.