The United States and many other heavily populated countries may face prolonged and severe drought conditions in the next several decades (see References 2). Faced with the potential for water-usage restrictions, many homeowners are investigating ways to reuse greywater, which is water from sinks and showers that is not contaminated with human waste. Approximately 74 percent of water used in most homes becomes greywater that could be safely reclaimed and reused (see References 1).
Attaching a hose or three-way valve to the drain pipe of a sink, shower or washing machine is the most common method for collecting greywater. Water drains into this pipe and out to a collection barrel or directly into the garden. If your system uses a three-way valve, you can switch between collecting greywater and allowing it to flow into the sewer or septic tank.
Homeowners should filter greywater before use to remove large particles. This filtering occurs naturally when greywater is used to water trees, bushes and other landscape plants; topsoil acts as a filter before the greywater reaches the roots of the plants. Some greywater systems use mulch basins -- mounds of mulch creating a basin or moat with the plant or plants in the center -- to filter greywater. Simply remove the mulch and replace it as needed. (See References 3.)
When using greywater outdoors, do not to allow the water to pool or collect. Standing water is a breeding ground for mosquitoes and poses the risk of contact with children and pets. While the chance of illness from contact with greywater is minimal, there is always the risk that it has been contaminated with human or pet feces. Avoid using toxic soaps, shampoos and cleaning supplies with a greywater system. Many of these products contain chemicals such as boron or chlorine bleach that are toxic to plants. (See References 3.)
The most common indoor use of greywater is for flushing toilets. The bucket method is simplest. Use a bucket to catch clear water that would normally be wasted waiting for the shower or bath to heat up. Pour this water into the toilet bowl for flushing. Placing greywater into the toilet tank can damage the flushing mechanism. (See References 4.)
- University of California Davis; Greywater Systems --- Benefits, Drawbacks and Uses of Greywater; Erin Reschke
- Wiley Interdisciplinary Reviews --- Climate Change; Drought Under Global Warming -- A Review; Aiguo Dai; October 2010
- "The New Create an Oasis With Greywater"; Art Ludwig; Oasis Design; 2006
- New Mexico State University; Safe Use of Household Greywater; Marsha Duttle; February 1994
- Jupiterimages/BananaStock/Getty Images