ASCE Policy Statement 332
WASTEWATER AND GRAYWATER REUSE
Approved by the Energy, Environment, and Water Policy Committee on March 22, 2012
Approved by the Public Policy Committee on May 4, 2012
Adopted by the Board of Direction on July 20, 2012
The American Society of Civil Engineers (ASCE) supports treated wastewater and graywater reuse as a water supply source for the beneficial uses of industries and communities, including agricultural, industrial, and residential uses. ASCE recommends the following:
- Maximize use of treated wastewater and graywater as part of any plan to develop water supplies where technically and economically feasible to do so and protective of public health and the environment;
- Encourage reuse of non-potable water when it can be provided cost effectively;
- Provide incentives, such as federal or state loans or grants, to local utilities for implementation of treated wastewater and graywater reuse, including pilot programs and research and development; and
- Update or establish requirements by state and local agencies that promote water reuse projects.
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 graywater reuse. The demand for water, including the need for water to preserve in-stream uses such as aquatic habitat and water-oriented recreation, is increasing. A portion of this demand can be met with treated wastewater and graywater reuse when technically and economically feasible. Water reuse should be an integral part of a water supply strategy. Public health and environmental requirements on the use and treatment of these waters must ensure water quality appropriate for the use. Public misunderstanding has led to “toilet-to-tap” or other derogatory phrases being coined in reference to increased used of reclaimed water.
Graywater is generated from bathtubs, shower drains, sinks, washing machines, and dishwashers. Graywater accounts for a large portion of the outflow produced in homes, but it is generally of higher quality than black water, or water from sewage systems. Historically, the potential for high concentrations of organic waste and other water quality concerns have been barriers for reusing graywater safely. Building Codes that allow for separate graywater systems should address these concerns.
Use of reclaimed wastewater for irrigation has been an accepted use for reclaimed water. Public acceptance of wastewater reclamation is a difficult barrier to cross for many communities to expand the use of reclaimed water such that it is a viable component of a community’s water supply portfolio.
The use of graywater 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 graywater reuse.
Wastewater reclamation refers to the reuse of domestic and industrial wastewater that has been treated to specific standards set by state, federal or local agencies that can be beneficially reused for industrial, commercial, agricultural and residential uses. Wastewater reclamation has been successfully used in many areas of the country.
The Environmental Protection Agency recognizes the need for water recycling through the reuse of treated wastewater for agricultural and landscape irrigation, industrial processes, graywater, toilet flushing, and replenishing a groundwater basin (groundwater recharge). According to the agency, water recycling offers resource and financial savings, and wastewater treatment can be tailored to meet the water quality requirements of a planned reuse.
Through the cost-effective reclamation and reuse of graywater, the total water resources available can be utilized more effectively to meet growing water needs by incorporating the principles of sustainable development.
ASCE Policy Statement 332
First Approved in 1987