Agree that harassment isn't the way to go about this, but I think we can put a good amount of blame on the individual here - selfish water usage doesn't seem like a great idea in California.
See my post bellow estimating how large their lot should be assuming golf-course irrigation. I came with ~5 acres
This individual is a jerk, no doubt, but 5 acres is small, so their overall usage compared to the total for LA county isn't very significant. LA county as a whole is abusing water.
I'd suggest a tiered pricing scheme. Current rates for water usage bellow what 99.9% of what the LA uses (to make it politically expedient), and two orders of magnitude larger otherwise.
