I really doubt water shortages are going to change anything in the near term. Probably not in my lifetime. LA doesn't have much natural water. But it is a population and profit center and it has both the wealth and political power to have water channeled to it. Which is a major reason it became a large megalopolis.

Las Vegas is another city that has water issues. It has essentially no natural water. Hasn't seemed to matter because the money and political power deigned that it would have plenty of water, cheap. Fact being that Las Vegas flaunts the incongruity of its existence. It is like there was a bet made that a person could build a prosperous city in the least likely place imaginable. A place with no water, not really along a well traveled route, a place where no food is grown, and there are no jobs or natural resources to exploit for jobs. Fact being that the place has absolutely nothing going for it. So they built a city. Just to prove they could.

As water gets more scarce and prices rise there will be increased pressure for conservation. There are a lot of places to save water. Especially considering that about 20%, by some calculations, of water use is wasted in leaks. Then there are lawns and golf courses. But there are people still harping about how their ten-gallon-a-flush toilet and high-flow shower head is a God-given right. That low-flow toilets and shower heads are infringements on their civil rights.

The history of money, population and politics all tell you that LA and Las Vegas will get what they need, as long as the money holds out. Massive water projects allowed both places to thrive. Does anyone doubt they can/will not do it again?