from my survey engineering course (which engineering major should you choose?) it's because reverse osmosis is a bitch to do, especially compared to cleaning se

from my survey engineering course (which engineering major should you choose?) it's because reverse osmosis is a bitch to do, especially compared to cleaning sewage or building dams. however, this isn't as huge of an issue as the article makes out because almost all of california's water goes to agriculture, and no one seems to have a problem with using grey-water for agriculture.