Although recycling or re-using toilet
water, or «black
water» — about one - third of
water use in the average household — is difficult, although not impossible, because of bacterial contamination,
grey water from baths, showers, sinks, dishwashers and laundry machines can be
treated and used to flush toilets,
water plants and gardens, even wash clothes.
There are good reasons for using composting toilets and for bringing them into the mainstream; all of the other
water that we use in a home can be
treated as
grey water and re-used for irrigation, green roofs and other useful things.