I think a more novel idea for the $2.5 billion they are spending on this would be a revolutionary technology for desalination. Survey feedback shifted from one in four in 2005 to three out of four after the drought that has decimated the non-existent water supply, 85% of which has to be imported from the Colorado River and Northern California. The newly discovered acceptance overcomes what the industry termed the "Yuck Factor" in peoples aversion to drinking recycled sewage. I find the damming and exporting of water more disturbing due to the decimating effect on the fish and indigenous tribes who once thrived on these rivers. The Colorado doesn't even make it to its river delta or the sea.
"The plan calls to initially recycle 15 million gallons by 2023 and 83 million gallons a day by 2035, about one-third of the city's water supply." Well that is all fine and dandy but what will San Diego's population be by 2035!? Sounds pretty dragass and halfass to me. Also Los Angeles has been boosting its recycling of wastewater, which started in 2008, from 70 to 100 million gallons.
Lots of water is likely wasted water some schmucks lawn, for irrigation and then doubly so for the livestock being fed grains already grown. Click here to view USG water charts for usage in the US. Meanwhile many believe that future wars will be fought over water, considered to be blue gold.