The problem in Arizona (and many other western states) is not the lack of fresh water but the use of fresh water–irrigation for crops such as cotton, alfalfa and letttuce, all water intensive crops that should perhaps not be grown in arid/semi-arid places.
And, the value of water rationing in such places (considering that up to 90% of the water can be going into irrigation) is in keeping cities from having to build more water treatment plants rather than simply saving water.
This is by no means a novel and unkown point, but up to now at least, the politics of western water have led to this rather bizarre and unfornate situation. Get enough thirsty senior citizens who vote though . . . you won’t need desalination.
Another problem that Cecil didn’t mention is altitude. For example, Arizona is not only many miles from the ocean, but much of it is thousands of feet above sea level. Even after you have fresh water, you mush then expend more energy to pump it inland and up. This limits the locations where desalination is practical to the strip of land along the oceans.
perhaps what Cecil meant is that Los Angeles could use desalination and stop stealing . . . er . . . taking so much water from the Colorado River and Owens Lake, thus making more water available for the inland people.
Not true. Riyadh, Saudi Arabia, which gets half its water from desalination plants, is 1,950 feet above sea level and several hundred miles inland. Yuma, AZ (elev. 160 ft.) is only about 60 miles from the Gulf of California, judging from the map. Tucson (elev. 2389 ft.) is about 150 miles away. Phoenix (elev. 1,090 feet) is only slightly farther. There are of course intervening mountains, but the use of siphons to get around changes in elevation has been known to civil engineers since Roman times.
I don’t want to minimize the difficulty and expense of building long aqueducts through difficult terrain, but we find numerous examples of this in California, New York, and elsewhere (granted these work primarily by gravity). There was some concern in the Great Lakes states that efforts would be made to pump lake water to arid western states a thousand miles away and several thousand feet higher in elevation. My recollection is that the governors of these states formed a compact to prevent this. Don’t be surprised if you see more big time water engineering proposals in the next ten years.