Compare this to alfalfa, an ultra-low-value crop the Saudis are growing in California because they bought senior water rights, then shipping to Saudi to feed cows, essentially laundering water.

Alfalfa is used/needed locally for cattle feed. Unfortunately for all of the noise over growing nuts in the desert nobody's talking about the immense amount of water used to raise cows.

https://www.sfgate.com/science/article/California-drought-No...

  But reforming the system would take so much litigation no California politician has dared to do it.

Yeah, it's a bit like Prop 13 in that respect. One only needs to drive down I-5 to see how militantly opposed farmers are to water conservation. California's got a vast system of aqueducts dating back sixty odd years and we're only now getting around to talking about maybe covering them to reduce evaporative losses.