Grey water is all wastewater that is discharged from a house, excluding blackwater (toilet water). This includes water from showers, bathtubs, sinks, kitchen, dishwashers, laundry tubs, and washing machines.
It commonly contains soap, shampoo, toothpaste, food scraps, cooking oils, detergents and hair. Greywater makes up the largest proportion of the total wastewater flow from households in terms of volume. Typically, 50-80% of the household wastewater is greywater. If a composting toilet is also used, then 100% of the household wastewater is greywater.
Not all greywater is equally "grey". Kitchen sink water laden with food solids and laundry water used to wash diapers are more heavily contaminated than greywater from showers and bathroom sinks. Therefore, different greywater flows may require different treatment methods that would render the water suitable for reuse.
The presentation about grey water unfolds the way of use and reuse of water in households, makes clear all the requirements in the utilization of grey water and provides practical knowledge.
Links to external material
- Overview of Greywater Management: Health Considerations (2006) World Health Organisation (WHO), Regional Office of the Eastern Mediterranean, Centre for Environmental Health Activities (CEHA), WHO, Geneva 2006
- Innovative Water Concepts – Service water utilisation in Buildings (2007). Berlin Senate Department for Urban Development
- Block 6: Integrated Water Concept - Ecological Integrated Concept. Berlin Senate Department for Urban Development and Housing
- Canadian Guidelines for Household Reclaimed Water for Use in Toilet and Urinal Flushing. Health Canada. 2010
- NSW Guidelines for greywater reuse in sewered, single household residential premises (2000) New South Wales (NSW) Government Health Department, 2000