[nerdchum]

From where?

I don't understand how that's possible. I don't know of any lakes or rivers or aquifers larger enough to provide water to almost 40 million people in California.

[reducesuffering]

The Sierra Nevada watershed

https://www.nature.org/media/california/california_drinking-...

The large greenery to the right is the Colorado River which provides 15% of CA water at the bottom.

[nerdchum]

Sierra Nevada watershed is already being used by Northern California.

It provides 60% of California water.

Even removing the farms, I couldn't find any data supporting that it was enough water for the rest of California.

But that doesn't necessarily mean that it can't either.

The data I found says the Sierra Nevada watershed supports 750,000 farms.

Is that equivalent to 15 million people or so?

[reducesuffering]

Californian agriculture is 80% of water usage. That agriculture is largely shipped out of state, internationally, and supplying the rest of the US half of its produce outside staple grains: fruits, nuts, vegetables, berries, etc.