Reusing wastewater is becoming a viable alternative to using freshwater in a range of domestic, agricultural and industrial situations. However, greywater can often be contaminated with microorganisms (such as bacteria and viruses) and other matter (such as dirt, lint, food and detergents).

Unless reuse is properly managed, pollutants in untreated greywater can lead to increased nutrient loads, reduced plant growth, algal blooms and health risks.