Earlier quoted context omitted.
Having better local sources of water and treatment may turn out to he a better idea than centralized water treatment. Here in the US, water is pumped (often uphill) and purified to drinking water standards, only for 70% of residential water used for watering green lawns. Those lawns are usually grown in a way where soil microbes are killed off, water retention capability are reduced (so it needs more water), and the…
In Irvine, California, homes are plumbed with two water lines: potable, and greywater. So even in the middle of a drought, everything is green.
You could reduce residential usage of water in California to zero and it would barely make a dent in the water shortage. California can relatively easily desalinate its way out of residential water shortage.
On the other hand, shutting down the agribusinesses in the Central Valley completely fixes California's water shortage for everybody.