Out of Sight, Out of Water: The U.S. and Mexico Have Only Just Begun to Grapple with the Aquifers They Share Posted on August 21, 2018 by Alan Day Texas and Mexico share 15 aquifers. The state and federal governments have done little to understand them. Source: Out of Sight, Out of Water: The U.S. and Mexico Have Only Just Begun to Grapple with the Aquifers They Share