“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.