>>Ok, say Cali imports it's water from the north east or north west. Both areas are going to see increasing rainfall due to climate change, so exporting some of that is a net benefit for them, insofar as it allows them to mitigate floods by storing excess and exporting it.<<

Floodwater is not potable and not easy to purify.

Also, they won't take from places that far away. They'll take from the closest states with enough water to rob.

>>Although, the repair issues just mean that American is going to have to put on it's grown-up panties and start acting like a mature society and not the Wild-West it used to be.<<

They can't. They literally cannot afford to maintain the massive sprawl of infrastructure they already have, let alone add more; but they only want to add more, not maintain what they have.