Of course, even if they're taking from their own well they're draining the groundwater just as effectively. It's hard to see how a market based solution wouldn't turn into a tragedy of the commons without enforcing limits on the extraction.
Yes, California's historical (lack of) ground water regulation and tracking was/is disturbing. Nobody has any idea how much is there or how much we are actually using.
There are limits on extraction going into effect [0], but it may be too late by the time they are supposed to happen.
A reality-denying, industry shill politician espouses: "Sinkholes arising from rapidly plummeting aquifers will boost the economy as tourist attractions. Water will be affordably trucked in and desalination is getting cheaper all the time. Problem solved."
