With less water on the surface, how long can Arizona rely on what’s underground?

In Arizona, verdant fields of crops and a growing sprawl of suburban homes mean a sharp demand for water in the middle of the desert. Meeting that demand includes drawing from massive stores of underground water. But some experts say those aquifers are overtaxed and shouldn’t be seen as a long-term solution for a region where the water supply is expected to shrink in the decades to come.