What is Water Reuse?

Water reuse is the sustainable use of effluent from wastewater treatment plants for beneficial purposes.

Water may be recycled for a variety of nondrinking purposes, such as industrial processes (e.g., power stations, mines, pulp mills, and refineries), or irrigation of public areas or crops. Purple pipe is used to differentiate pipelines carrying recycled water for nondrinking water purposes. The quality of recycled water varies with the treatment process being used, but the water receives enough treatment so that it is fit for a nondrinking purpose. 

Highly treated water can be used to augment drinking water supplies that come from groundwater aquifers or surface water sources. The addition of highly treated water to groundwater aquifers, in a process known as groundwater recharge, also helps to prevent saltwater from mixing with drinking water supplies in coastal regions. Highly treated water from water purification processes also may be recycled back into the drinking supply without prior discharge to the environment. In the United States and Australia, regulators have discussed the need for guidelines to be developed for this purpose.