“Grey Water” sounds strange but in the plumbing world it defines domestic water that has been used and with some basic treatment can be reused for certain purposes. First off, what kinds of water can be reused? Water from a lavatory sink, a tub or a shower is all that can be reused in a home setting. The toilet water cannot be reused for obvious reasons and the kitchen and laundry also cannot be reused because they each have sufficient contaminants that would yield the water unsafe.
How can we reuse water and what can it be reused for? The water after it has been used will go through a basic filter process and then be stored. Because of stagnation issues only enough water can be stored that will be used in a fairly short time. The water must also be died a color so that it is easily distinguishable from potable water (drinking water). The pipes that carry the reused water are also supposed to be colored purple to prevent any cross connection from happening in the future. The most common use for reused water is for the flushing of toilets or urinals. When a reuse system is used the toilets will have a water supply from both the reused water and the potable water so that in the event the reused water is used up the toilet will still fill with water.
Water reuse is still in its infancy and almost no municipalities have gone so far as to allow it in residential settings, but it is coming and it will be a small but positive step forward in water conservation.
