That's another good point. Then the only way I could see it working universally is if you assign a price to the water consumed, where it's costlier in CA than VA.
Then you can say that a single almond grown in CA uses $.001 H2O, but in VA it's $.0001 H2O, or something like that.
It's just a thought experiment, of course. But it seems like a worthwhile one, if only to introduce the idea of accountability for the cost of water consumption in various foods.
The normal way to do this is to charge for the ingredient at source. It seems easier to change the California laws (constitution?) so that agriculture pays per gallon of water.
I don't know the specifics in California but property rights in water are complex, especially in the Western U.S. A mere change in regulations, even under a state constitution, might constitute a regulatory taking (i.e. a taking of property requiring just compensation under the 5th Amendment).
Because the issues are so complex, the legal terrain so unclear, and the consequences of an adverse court ruling so substantial, not to mention the politics, legislators are reticent to impose such strong measures.
Water laws are loose because they were written in a world where groundwater is almost as plentiful as air. Locations where this is still true should keep their simple laws (nobody wants a trillion detailed laws if there is no need), but places like California need to get more sophisticated.
Then you can say that a single almond grown in CA uses $.001 H2O, but in VA it's $.0001 H2O, or something like that.
It's just a thought experiment, of course. But it seems like a worthwhile one, if only to introduce the idea of accountability for the cost of water consumption in various foods.