Leto’s sacred precincts I would say are usually be near rivers. That said I think that it is even more auspicious to recognize sacred space to her in any area where ground water rises. This would include wells, natural springs, and water within cavern systems. Much of this has noted regional connection with A pollon that could have come by via or in connection with his mother Leto. This of course plays off the hereditary relationship at Delphi and the myth of the dragonness Delphyne.
In the household, given this transitional fluid and liminal nature of Leto, the most sacred place for her would seem to me to be at the doorway, where both her children also reside in their domestic cult.