Why do people think water "isn't a commodity"? Tell that to Ozarka and the farmers battling for the rights to use the same aquifer. The water in there is decreasing, and will eventually be gone. Agriculture in that area might collapse, because water IS a commodity, especially aquifer water (aka Spring Water).
The Edwards Aquifer that's partially in Texas is also an issue. Farmers are using more water than gets put in. If you drive through Austin you'll see signs like "Entering Edwards Aquifer recharge zone" or "Entering Barton Creek Watershed". The reason they are there is because of the susceptibility of the aquifer to pollution. Dump motor oil and it's going straight through (limestone caves don't filter like sand and clay do).