One is forbidden to recite any Davar Shebikedushah in a lavatory (the room one uses to relieve themselves), even if no foul odor is present. Once a room has been designated to be used as a lavatory, even if it has never been used, the previously mentioned Halachos apply to this room. A room that was used as a lavatory and now the toilet was removed and the hole is covered, no longer has the status of a lavatory.