Every year, countless gallons of water flow through dishwashers, washing machines, and showers in people's homes. Almost always, this water goes straight out the drain once it's been used. But why is it that we automatically assume that water is useless after it has touched our clothes or skin?

Somewhat recently, a movement has arisen (or re-arisen, if you will) to refute this idea and begin reusing wastewater in an attempt to cut back on excessive water-use. Wastewater that has been used in the home, (except that from toilets and garbage disposals) is defined as greywater. Because it has only been used for limited, generally safe, and pollutant free purposes, greywater can be used again safely after minimal treatment.

The most common use for greywater is for landscape irrigation, which we all know can be costly and wasteful when using fresh drinking water. Essentially, instead of letting our largely uncontaminated water run down the drain into oblivion, we catch it and use it to again to irrigate a garden. Greywater irrigation can enable us to not only reuse an increasingly precious commodity, but also to improve our lives, homes and gardens.

A typical greywater irrigation system consists of three general parts: the greywater source (ie. the shower), a receptacle that keeps greywater separate from blackwater, and a basic system of pipes that transports the greywater from a bathroom or laundry room onto a garden, raised bed, or lawn. Laws vary by state regarding large-scale renovations to incorporate alternative wastewater systems into your home, but greywater systems can be very effective even on a small scale without a large renovation. Consider switching to all biodegradable soaps, shampoos, and toothpastes, and directing a pipe from an upstairs sink out a window (think: gutter) and onto a small tomato plant. Or start by simply saving mildly-soiled dishwater in a bucket and watering your flowers with it! Big- or small-scale, transitioning to greywater systems can make a huge difference in your home and on your water bill. 

If you're considering implementing greywater irrigration in your home, make sure to review the rules and regulations surrounding greywater in your state and municipality. Many states and local governments are in the process of revamping greywater laws, and it's important to follow the building, water, and power codes of your region. A great place to check out where your town falls in the greywater policy spectrum is the Gray Water Policy Center, found here. Before altering any of the plumbing systems in your home, it is important to understand the differences between greywater and blackwater. Blackwater is wastewater that comes from toilet waste, and needs more time to decompose, contains higher levels of nitrogen, and contains more pathogens than greywater. For obvious reason, blackwater should not be used to irrigate any soil that is used for gardening, nor should it be mixed with greywater.

It is also important to remember that if you do not have a treatment system for greywater, all products put into the water must be biodegradable.

Greywater irrigation systems offer an eco-friendly alternative to watering your lawn or vegetable garden with fresh drinking water. Try recycling your greywater and see what happens! 

Photo credits: Royal Horticultural Society, Green Vision Corp