Overview of Greywater Reuse: The Potential of Greywater Systems to Aid Sustainable Water Management

As pressures on freshwater resources grow around the world and as new sources of supply become increasingly scarce, expensive, or politically controversial, efforts are underway to identify new ways of meeting water needs by expanding the usefulness of alternative sources of water previously considered unusable. Greywater reuse is one such strategy.

Greywater is the relatively high-quality wastewater generated from household uses like bathing and washing clothes. When reused either onsite or nearby, greywater has the potential to reduce the demand for new water supply, reduce the energy and carbon footprint of water services, and meet a wide range of social and economic needs. In particular, the reuse of greywater can help reduce demand for more costly high-quality potable water.

The 2010 report Overview of Greywater Reuse: the Potential of Greywater Systems to Aid Sustainable Water Management analyzes how, as a key strategy that reduces demand, greywater reuse can improve the resilience of water systems to the impacts of climate change. It also serves as a relatively secure or drought-resistant source of water supply because presumably greywater generated from showers and washing machines will continue, if at a reduced rate. And in helping displace demand for water, greywater reuse can help reduce conflicts over water and reduce the demand for new water supply projects as a result of climate change.

The research shows that when the systems are designed and implemented properly, possible public health concerns with using different water qualities can be addressed. As greywater reuse becomes more widely adopted, regulations can be put in place to ensure that water quality is appropriately matched to water need.

This paper provides a broad overview of the state of greywater implementation and policy, with a special emphasis on the Middle East. It examines the potential of greywater to reduce the water and energy intensity of water uses, and it analyzes key issues that must be addressed for greywater to be accepted, and implemented, at larger scales.