Water cliche alert.
The former mayor of Phoenix wants to see desalination plants lining the Sea of Cortez to supply future water needs in Northern Mexico and Southern Arizona because he says "water is going to become, if it’s not already, more valuable than gold or oil.” Apparently the economy is humming along so nicely in Phoenix they believe they are going to be the next Saudi Arabia. Why Saudi Arabia? Because that is the only place I know of relying heavily on desalinated water for municipal and industrial (M&I) needs (it may have something to do with the cheap cost of power in that region). If you're talking about using desal to supply irrigation water (which is where most of the water is used within areas that border the Sea of Cortez) you are in similarly sparse company. Israel and Spain are about the only places currently using desalinated water for irrigation on anything resembling a large scale and much of that use involves treatment of brackish groundwater rather than seawater. Those types of waters have a much lower dissolved mineral content than seawater, so production costs are also much lower, but it still isn't cheap water.