Approved by the Energy, Environment, and Water Policy Committee on August 30, 2010
Approved by the Policy Review Committee on September 1, 2010
Adopted by the Board of Direction on October 19, 2010
The American Society of Civil Engineers (ASCE) supports and encourages greywater reclamation and reuse. Greywater refers to the reuse of water drained from baths, showers, and sinks (household wastewater excluding toilet and urinal wastes) for irrigation and other water conservation applications. Through the cost-effective reclamation and reuse of greywater, the total water resources available can be utilized more effectively to meet growing water needs by incorporating the principles of sustainable development. ASCE recommends the following.
- The use of non-potable greywater should be encouraged when it can be provided at a reasonable cost and the public health and environment are protected.
- The safe use of greywater should be maximized as part of any plan for wise water resource management for non-potable uses where technically and economically feasible to do so.
- Incentives, such as federal and state grants and/or loans, should be made available to local utilities for greywater use planning studies, pilot programs, and research and development.
- Requirements set by regulatory agencies for water reuse projects should have a balanced and sound scientific, environmental, engineering and financial basis.
Sound water management consists of a variety of strategies to maximize the sustainability and wise use of limited water resources. Water management strategies include water conservation, water reclamation and reuse and greywater reuse. Greywater is of lesser quality than tap water, generally greywater is wastewater from bathtubs, shower drains, sinks, washing machines, and dishwashers. Greywater accounts for a large portion of the outflow produced in homes, but is generally of higher quality than blackwater, or water from sewage systems. The potential for high concentrations of organic waste and other water quality concerns are barriers for reusing greywater safely.
The use of greywater has been successfully demonstrated. Treatment technology is already available, and in some cases fully implemented, to provide safe, reliable non-potable water supplies that can be developed from greywater reuse.
Many productive non-potable uses of water can be served with greywater reuse. The intent is to encourage the cost-effective reuse of greywater practices, consistent with protection of public health and water quality. Increased water demands and changing climate patterns can result in water shortages. One effective method for reducing potable water use is the use of greywater in place of potable water for some appropriate uses.
ASCE Policy Statement 534