In the opening scene, Niles confesses to feeling lonely, to which Daphne replies, "...perhaps all you need is a little company at the apartment." This is one of the few references made during season three to where Niles has been living since his separation from Maris.
In "The Last Time I Saw Maris," earlier in the season, Niles states that he has rented "a bachelor pad." There is also a brief reference by Niles to his "new address" in the episode "Come Lie With Me." We learn nothing more about where Niles lives until he rents an apartment at "The Montana" in season four's "To Kill a Talking Bird."