The argument essentially looks like this: there is a water problem; keeping a green lawn is not part of the problem; let's find out where the problem lies. The assumption made here is that the water used to keep lawns green is not part of the water problem. Countering this assumption would require some form of statistical analysis or syllogism. Since my uncle is arguing from a generalization that he apparently discerned at some point, it becomes necessary to correct that generalization. If my uncle is swayed by facts, facts then are what are necessary. One could look to the Los Angeles Department of Water and Power -- an authority on the subject -- to find out the statistical analyses.

By doing so, one could also see the benefit of cutting water costs -- the Los Angeles Department of Water and Power offers a significant rebate for customers whose water usage is below normal allowance. This latter argument, of course, would only work as a corollary to the main argument; nonetheless, it could prove to be as effective as the first.

The third argument is a kind of transitional argument. My uncle states that what everyone takes for a water problem is not really a water problem at all -- but something else entirely: a scheme cooked up by liberals looking to profit. It is essentially the same sort of transitional argument that Galileo used to discount the Ptolemaic model of the universe (held by the Church in the medieval age) in favor of the Copernican model, which placed the sun at the center of the universe. There was no way to disprove either model (for to what still point in space could you travel to observe the motion of the universe?) -- there were merely the philosophical and pseudo-scientific...

What my uncle attempts to show is 1) there is no water shortage -- the better explanation for why xeriscaping is being promoted is that such-and-such stands to profit by it; and 2) if there were a water shortage, there are surely bigger consumers of water (such as farmers) than residential landowners with green lawns.
My uncle's transitional argument is perhaps his best: it throws doubt upon the whole premise of xeriscaping. By insinuating that it is not even a noble enterprise to begin with -- but a ploy on the part of an undesirable element in society to grift good, hard-working Americans (who desire nothing more than a respectable lawn) of their good, hard-earned money, my uncle sets up a model in which xeriscaping is just the tip of the iceberg: underneath is an entire, elaborate political scheme to defraud the laborer of his wages and his aesthetic domestic beauty. This is the same tactic, no doubt, that Galileo employed to draw followers to his side: the Church was corrupt and tyrannical.

The answer to this argument is the same respectful one that St. Robert Bellarmine used against those religious who sided with the Copernican model: it was simply neither true nor fit that the universe should revolve around the sun and not around the Earth, upon which the Lord and Savior Himself had walked. Xeriscaping is simply a return to the natural aesthetic charms of Los Angeles flora. It may not solve the water crisis, but every little bit helps -- how could it not? Therefore, to assert that water is not wasted is merely to refuse to admit the evidence and to refuse the natural beauty of the natural climate.