
Quoting
DELETION OR EXPUNGEMENT
You may request deletion or expungement of CHRI [criminal history record information] in the WSP [Washington State Patrol] if: (1) the file consists only of non-conviction data; (2) you are not under prosecution and you have not been arrested for or charged with a new crime; and either (3a) two years or longer has elapsed since the record became non-conviction data as a result of the entry of a disposition favorable to you, or (3b) three years or longer have elapsed from the date of arrest or filing of charges and you are not a fugitive and the case is not still pending in court.
Information regarding how to make a request for deletion or expungement of criminal record information may be obtained from the WSP. Following the WSP's procedure will not delete or expunge CHRI in the possession of a local police agency. A separate request must be made to the local (arresting) police agency in accordance with that agency's procedure.
You may not obtain the deletion or expungement of a record related to a case that resulted in a conviction or other disposition adverse to you. Examples of dispositions that are adverse to you include the entry of an order to dismiss entered after the successful completion of a period of probation, suspension, or deferral of sentence. However, when the superior court has vacated your felony conviction, the public will not have access to information about the conviction in your CHRI.