Legal Question in Employment Law in Washington

That depends. If you live at your place of employment (as, for example, in the case of an apartment manager), you should probably expect that to happen once in a while. Otherwise, depending on the circumstances, it probably is legal, but is a little odd unless there is a good reason. Nothing says you have to let the employer in, though. If they insist on coming in, you may have a case, particularly if the employer was not invited and sexual harassment is implicated.