In the grammatical sense anyway. One of my hobby horses is to oppose putting “only” too soon in the sentence. Do a search on only to find more examples.
Many people put “only” in the location equivalent to right before “toilets,” but if you put it there, the error is too obvious to miss.
You could argue that the really correct place for “only” would be before “someone.” That allows for the toilet to work at least some of the time at someone else’s house.