The amazing part is, they are now being allowed 50% of their current water usage, after they cut 50% on an every-year basis a few years back. So, this summer they are only using 25% of what they once used.
Unfortunately, that math is why many golf courses don't lower water usage voluntarily ... they wait until they are forced to do so, because they are afraid 50% of 50% won't be enough.
What really should happen is for golf courses to come up with a standard number to water 18 holes, with a formula to adjust for the local climate, and make everyone operate from the same basis. But they are unlikely to do it voluntarily as a golf group, and God forbid that local politicians be allowed to decide the number. So you wind up with every different course trying to grab the most water they can, to protect themselves from the politics, and from their competitors.