Approximately 150 liters of water are consumed per person per day. About 60-70% of this water turns into recyclable greywater. Greywater is a percentage of the waste water derived from domestic use, excluding toilet water, and can be divided into the categories of light and dark greywater. Light greywater includes shower water and water from sinks that are exclusively used for washing hands (such as bathroom sinks), and contains a low concentration of pollutants. Dark greywater includes water from washing machines and kitchen sinks, and contains a higher concentration of pollutants.
Greywater contains organic substances, remainders of chemicals from cleaning fluids, and microbial and pathogenic contamination. The concentration of pollutants in greywater makes up between a third to half of the contamination in urban sewage, and as a result it can cause damage both to the environment (in the form of contamination of water sources, damaging the quality of the soil and harming plant life) and to the health of the public that comes into contact with the water.