What is grey water?

Grey water owes its name to its murky appearance and because it is somewhere between potable freshwater and wastewater. It is a resource which, once recycled, can replace other water sources for some common uses.

Grey water or used water is the term used for domestic wastewater generated in homes and commercial buildings, without faecal contamination. Grey water contains organic and inorganic material, and microorganisms. Grey water has less nitrogen and phosphorous than black water, and pollutants in grey water usually decompose faster than those in black water.