We were helping a commercial client analyse their water use at the moment. In that process of inspecting every single water appliance within a 30,000 m2 building, we came across a very real example of how the water and energy nexus comes together at the end use.  See this video below for how much water is used in a cooling tower.  And this was in the morning, well before the afternoon heat peak has arrived.  

The water and energy nexus is apparent at all scales - from energy generation through to distribution of water, through to the combination of systems that use both energy and water in houses, apartments and commercial buildings.

Just think of how many buildings in our town or city have these systems pumping away on top of the building!