I'm assuming you're talking about desalination.
There is that. The bigger issue is transportation. There's plenty of water, just not where we need it at the moment. And we have to restore contaminated water. Time to build some big-ass, nuclear powered tunnel boring machines, and pipe it around like oil, gas, and battery acid. And after bailing out the bankers, I don't want hear anybody crying that we don't have the money. There's plenty of that also, just not where we need it at the moment...
It's not like this is a new problem. Solutions were developed as far back as the 1960's, and many politicians promoted those plans as early as 1978 and warned of the dangers of doing nothing. But nobody listened. And it kept getting worse, and still nobody wanted to invest in it. There just wasn't enough corporate profit in it, politicians can succeed by ignoring it, and there is simply no stomach in the US electorate for taking on some pain to alleviate future problems.
So here we are. Carly Fiorina called out Jerry Brown for decades of needing infrastructure and the blockage of any progress by back-to-nature ideologically opposed to dams, canals, even reservoirs in California, so nothing got built and their paying for it now.
And no, it's not like "Climate change" where huge investments are maybe going to mitigate some warming, how much and whether any of it will work is questionable.
We have proven, practical solutions for storing and transporting water and, yes, even desalination where it's needed (just check out the projects in Dubai). But nothing happens. Worst drought ever in California, and what does the leadership say? Saving water for the future is "utter ignorance". Really? Seems I remember ancient Egyptians even knew enough to store food in case of famine.