California had a 200 year megadrought in Medieval times [1]. Mother nature doesn't care that we built a state of 40 million people on top of a drought prone region. A megadrought can and will hit CA again. Who knows if it's going to be this century or not, but it very well could and there's not a damn thing we can do about it. We don't control the rain.
[1] https://www.peopleplacesandpastimes.com/california-drought-p...