In the midst of this crisis, there's something Los Angeles can do right now to help. I found the information in a Time article linked here.
There are several ideas, but here's the one that would help most:
Finally, there is the kind of water that we throw away: wastewater. We should recycle it. And we already do. The city’s wastewater treatment facility in El Segundo is an engineering marvel that treats dirty water and sends it into the ocean. Every day, L.A. pours nearly 300 million gallons into the ocean. Yes, that bears repeating: we dump millions of gallons of highly treated water into the Pacific Ocean every day.Desalination is expensive, but right now LA is dumping clean fresh water to the ocean. Instead, LA could do a bit more purification and have 100 million gallons more of drinking water every year, saving vast quantities of water that would normally be shipped from Colorado and Northern California. Would I drink that "toilet to tap" water? You bet. Municipal sources of water already contain some amount of treated wastewater, it's just usually gone through a river or lake first. The purified water like Orange County produces would be even cleaner than what I'm drinking now.
Why not keep that water here instead?
Right now, Orange County takes wastewater and treats it to ultra pure levels, producing 10 million gallons a day of water that is superior to bottled water in quality (both by chemical analysis and blind taste tests). In the OC, they have effectively duplicated the process of purification that takes place in nature, only much faster. I have drunk this water, and it tastes like any bottled water. Orange County takes this water and dumps it onto the ground to be naturally filtered, so that it can replenish groundwater to supplement drinking supplies.
With wastewater recycling, L.A. could produce 100 billion gallons of bottle-quality water a year, or about half of our total water needs. This is a supply that is not dependent upon a distant source or subject to interruption by economics, politics, or damage to the water transport system. There is a plan from LADWP to recycle this water on a small scale, but it does not take full advantage of the opportunity.