My water supply is provided seasonally from melting snow and rainfall. I highly doubt much of that water is trucked the thousand or so miles to California.
Using this seasonally supplied water today won't mean that we have less in the future. Not unless we are hoarding it all, but our reservoirs are only so big anyway, if they were filled to the brim, and that water weren't being used, it'd just be dumped down the overflow and would find its way to the ocean... which is coincidentally where it ends up anyway when I divert it for a nice long shower.
I'm not going to cut back on my excessively long showers just because Californians won't cut back on the damn tree nuts. I'll gladly do my part and cut down on Californian nuts though.
Water is a global resource. If your water isn't exported right now doesn't mean it won't be in the future. A huge amount of the US is dependent on groundwater reservoirs. When those reservoirs run out, they'll need to import water from places that don't depend on groundwater or (more likely) move. You may be able to take long showers now, but if we as a nation (or even species) are going to get through the long term consequences of global warming, we're going to need to learn to reduce our water intake. Why not start now?
I would claim water - groundwater - is a local resource, not global, as a certain part of a country is dependent on a particular reservoir.
Of course, water can be bottled or put into containers or tanks and this water can then be transported across the world. People are shipping branded water bottles back and forth, and it is often stupid (Can you spell "Evian" backwards?), but not entirely different from all the other material flows in our global economy.
Still, in any amounts relevant for agriculture, water is a local or a regional resource.
The problem was: sewage systems need excess water to work, and since Germans were so diligent about saving water...well, that was a problem. Of course, the obvious solution is just to pump some of the saved water back into the sewage system, but that requires additional infrastructure.
That is no wonder, because the Germans seem to be extremist with this. We have had similar problems in Finland: my local water utility had to flush some clean water straight to the sewage system, because people started saving water and sewage lines started to clog up.
You can get around this problem partially by designing the sewage system to deal with this (handles better a larger portion of solid matter in the wastewater, includes pipelines for flushing fresh water through it).
Still, too much frugality is not a good thing. We nowadays use washing machines and dishwashers that are built to German specification.
The washing program is a compromise of water amount, temperature, duration, and mechanical wear during the wash. We now have machines where the water amount and temperature are prioritized. Thus the washing program takes a long time, and it puts a lot of mechanical wear to clothes.
This is OK for Germany, where water is somewhat scarce. You have one city pulling its water from the Rhine, purifying it, using it, and putting the managed wastewater back to the Rhine, then the next city a few kilometres downstream does the same, and then the next. The purification is an expensive process.
But we don't have that; we have a pipe from a lake that contains already-drinkable water in abundance, and it needs just a bit of cleansing of solid matters before delivering to consumer pipes, and it is better than in Germany. Then, after using this water, the wastewater needs to be managed, regardless of where the clean water came from
But now the bottom line is, we save water that we wouldn't need to save, then we flush sewage pipes with fresh water, and when I put my clothes to my Miele, I wait for two hours to wash the cotton program, and wear out the clothes too soon because the washing machine rubs and whirls them half-dry.
You are not entitled to another region's water. If you want somebody elses water, you should be prepared to pay dearly for it.
If that other region happens to be running low on water as well then that water may not be for sale. If that is the case, you should prepare to pay very dearly for it. Countries have been broken up, and wars waged, over far less.
Using this seasonally supplied water today won't mean that we have less in the future. Not unless we are hoarding it all, but our reservoirs are only so big anyway, if they were filled to the brim, and that water weren't being used, it'd just be dumped down the overflow and would find its way to the ocean... which is coincidentally where it ends up anyway when I divert it for a nice long shower.
I'm not going to cut back on my excessively long showers just because Californians won't cut back on the damn tree nuts. I'll gladly do my part and cut down on Californian nuts though.