GRAY WATER
“Gray water” is wastewater collected from washing machines, bathtubs, showers, and laundry room or bathroom sinks.
If properly collected and stored, it can be safely recycled, thereby reducing fresh water consumption. Reuse of gray water can also reduce the load on septic tanks and leach fields.
Gray water is distinguished from “black water,” which is wastewater from toilets, kitchen sinks, and dishwashers. Black water should never be reused in the home because of possible contamination by bacteria, viruses, and other pathogens.
Gray water may contain food particles, detergent or soap residue, and possibly some human pathogens. But as a general rule, gray water does not require extensive chemical or biological treatment before being used for landscape irrigation. It is best to use gray water on ornamental plants, lawns, and trees rather than on food plants, especially those that are often eaten raw.
Wastewater from the shower or lavatory sink generally contains only a small amount of soap, and has few solid residues. However, from a plumbing standpoint, wastewater from a clothes washer may be much easier to recycle. You can use special detergents in order to lessen any potential harmful impacts on plants.
Gray water may be immediately redirected to landscaping, or it may be stored for later use. When stored, filtering the water becomes more important in order to reduce pathogen growth. Gray water should not be used for dust control, cooling, spray irrigation, or any other use that would result in airborne droplets or mist.