English: A schematic of the water system used in many earthships (see http://www.earthship.com/water ). Clean rainwater is used throughout all of the house's domestic equipment in a particular order (bathtub/shower, sink/dishwasher, and then flush toilet). Owing to the order, which pollutes the water in a staged manner, the water is much more effectively used. The replacement of the flush toilet with a composting toilet would be even better, but the system presented here is more easily adaptable to existing houses since most people already own and use a flush toilet. Note that the water-organising module is composed of a filter (depicted in green) and a pump (depicted in blue). The parts that pollute the water are depicted in brown.