The idea that they own the water and have a right to sell it is screwy on the surface
Exactly.
It isn’t theirs to sell.
Taxpayer money built the dams, reservoirs and delivery systems that provide the water.
Taxpayer money subsidizes the cost of the delivering water to farmers for the intended purpose of farming.
At the very least, if the water isn’t used for farming they should lose their quota or allotment.
But the best and fairest solution is to stop all farm subsidies and price supports and end all quota and allotment programs.
Let market forces set produce prices and it will probably end up costing the same or less.
In my state the State subsidizes corporate dairy farms, sets artificial price support levels and then restricts shipment of lower cost milk from other states.
Same with sugar and other agriculture products.
Guess what industry gives state politicians the biggest financial contributions.