Once vacated, the State Patrol will seal the conviction from public disclosure. Washington State Patrol is one of primary sources for private agency background checks. However, there are some computerized indexes that may show the notation "case vacated" rather than the charge or the conviction offense, after a court enters an order to vacate. In addition, the conviction can still be used in a later criminal prosecution.
Once an individual vacates a conviction record, State law gives that person the right to state to anyone, including prospective employers, that you were NOT convicted of that offense.
I do not believe it is on your public record still, but I have found that many private companies store arrest records and do not keep track of the records being vacated or expunged.