Wash. Supp. L. R. 2.031
In civil actions, the designation of a known party by a name other than the party's true name shall be allowed only upon a motion and declaration establishing good cause, and an order of the court. In determining whether to designate a known party by a name other than the party's true name, the court may consider whether the moving party is a minor, whether the moving party was the victim of child abuse, whether the moving party was the victim of sexual abuse or assault, or any other criteria that warrant pseudonymous litigation.
If ordered, the designation of such party shall be by use of such party's initials or a fictitious name other than "Jane Doe" or "John Doe." The name "Jane Doe" or "John Doe" is reserved to be used for a party whose identity is unknown and the party is being designated as provided in ORCP 20 H.
Wash. Supp. L. R. 2.031