That's not really true except perhaps on the shallowest level. There's a lot of environmental issues, pre-1914 water rights, short-term climate issues like ENSO and MJO, and crop choices that have caused California to experience water shortages. Maybe in some cases we can put crops under solar panels to save water[0], or reclaim more water through toilet-to-tap programs. You know, through infrastructure.
Reductionist statements like yours never really reflect any real-world policy environment. The real world is messy and complicated.
[0]: https://arstechnica.com/science/2019/09/crops-under-solar-pa...