Can your car be repossessed from your work if it is private property in Washington state?

Yes. The repossession agent may recover the vehicle so long as he has free access to it, on private property, public property, federal property (with the proper permits), even a limited (key card) access parking garage so long as he is given access to the garage. Keep in mind that hindering the repossession of a vehicle is a crime in most states. In situations when this has happened, the agent or the lender may seek a replevin. In the event a replevin is acquired, it will be served by a law enforcement officer accompanying the recovery agent, you will be ordered to surrender the vehicle, and your failure to do so will land you in jail and the LEO will supervise the recovery of the vehicle anyway.

Your choices then, when a vehicle is up for repossession is to surrender the vehicle voluntarily, or give the recovery agent grief and give him a reason to take it when it is easiest for him and most inconvenient for you. Consider that recovery agencies are in the very specialized business of finding and securing vehicles that those who haven't paid for them are trying to hide. In six years of skip tracing, no one ever got away from me, and there are skip tracers out there far more skilled than I.