2 links have been added on this idea.
  1. Yeah over half of the water that goes through your home is grey water, which can be used for the majority of uses of normal water. Got to be done one day – even if its just to teach people not to waste in general.

  2. Bit drastic, but it would provide them with free water to feed the garden trees and plants. If that’s the type of building you think we all live in. Hmm