A building's waste-water (excepting kitchen sink and toilet water) can be safely routed to irrigate outdoor perennial gardens. Greywater-safe soaps and detergents must be used, but this wholesome method of water recycling can completely provide for a landscape's water budget.
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The Laundry-to-Landscape method of greywater reuse, pictured above, is the simplest version and requires no permitting in most counties. The tub is completely optional, as greywater can be routed straight into basins around fruit trees and shrubs for year-round irrigation. In the above example, we are simply getting an additional use out of the water by having it feed cannas before it is routed to a fruit orchard. The entire system is gravity-fed, as can be accomplished in any situation where the landscape is level or downhill relative to the washing machine. Shower and bathroom sink water can also be used in this way. This can save up to 50,000 gallons of water per year for an average household!