Legal Language Services ranks Washington as a state with heavily regulated legal interpreting requirements.
Your legal interpreter must have the appropriate level of certification that meets your language needs. This is especially true if you require an interpreter who will be working in a courtroom.
This does not mean, however, that you should hire a certified interpreter for every situation.
In addition to statewide requirements, some legal venues in Washington require that legal interpreters be certified by specific organizations. Whether or not an interpreter is certified — let alone the level of certification — will have an effect on how much you are charged for legal interpreting services.