What is Greywater?
Greywater is what goes down the drain from your shower, tub, laundry, and sinks, and accounts for about 1/2 of residential water use. Greywater is only “gently used” and can be legally diverted into the garden for watering your home landscape. In these times of extreme drought, residential greywater systems are a sustainable and cost-effective way to reduce water use and maximize the impact of this precious resource in our homes and gardens.
What is a Residential Greywater System?
A residential greywater system can be as simple as plumbing water from the clothes washer in to nearby landscape plants, to designs that include shower, tub and sink water being diverted into a branched drain irrigation system in the garden. A well designed greywater system saves the homeowner thousands of gallons of water a year, and allows the household members to easily choose when they want greywater to go into the landscape or into their existing sewer or septic system.
Why Install a Greywater System?
Greywater systems have a number of advantages. They reduce the amount of water needed for the landscape and garden, which results in lowered water bills or less electricity use from pumping well water. If you have a home septic system, diverting greywater will reduce the load on that system and may help extend its life if it is an old or overloaded system. If you use a municipal sewer system, you will be reducing the load on that system and the energy required for water treatment. And of course, greywater systems will result in the use of less water, up to 40% less, and preserves it for other critical uses in the ecosystem and community.
Codes & Safety
Residential greywater systems are legal in California, but do not include water from the kitchen sink or toilet (these are considered “black water” by the California Plumbing Code or CPC). Greywater systems are an excellent choice for watering landscape plants: trees, orchards, perennials, and most veggies but is not suitable for lawns, sprinkler systems, or edibles that will come into direct contact with greywater such as root crops and lettuce.
Greywater systems should deliver water into the landscape in such a way that it readily sinks in and does not collect into puddles. Greywater should not be stored in containers for longer than 24 hours.
If you use a greywater system at home, its important to avoid using soaps and other products that contain sodium or chemicals that can damage or kill plants or other living organisms in the soil. See resource link below for more details on recommended soaps for greywater systems.
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