How come ZamZam water in Mecca never runs out?
The Zamzam Well is located in the Wadi Ibrahim. It accesses water from the wadi alluvium and from the bedrock. 


  Water in the well comes from absorbed rainfall in the Wadi Ibrahim, as well as run-off from the local hills. Since the area has become more and more settled, water from absorbed rainfall on the Wadi Ibrahim has decreased.