What is “Greywater” and what can we do with it?

Greywater is household wastewater such as dirty dish water, shower run-off and the waste water from the washing machine. It basically consists of non-faecal contaminants such as food, grease, dirt, hair and detergents.

If you live in a suburban area, your Greywater is diverted into the city’s waste water system where the water typically goes to a treatment plant and then into rivers or out to sea. Whilst the treatment of wastewater can remove most solid matter and pollutants, it is not full-proof, and pollutants that we tip down the sink can end up in our waterways and alter the ecology of natural areas. Research has shown that phosphates and surfactants in detergents can have a detrimental affect to freshwaters, causing algal blooms, releasing toxins and depleting the oxygen available to aquatic life1.

The good news is that if we are careful about the detergents and cleaning agents we use around the house we can put our Greywater to better use by diverting it into our gardens instead of simply letting it go down the drain. Figures show that one Australian household can waste up to 400Litres of Greywater per day2, and in a country prone to drought, this untapped resource could make all the difference.

There are a few ways to divert your Greywater into your garden at home such as having a Greywater system installed however, a simple bucket or hose for transferring the water from your sink, shower or washing machine will achieve the same outcome:

  1. Keep a bucket in the shower to catch the water whilst you wait for the water to get to the right temperature.
  2. Half fill your kitchen sink for hand washing dishes and use less soap. If you are lucky enough to have a dishwasher, make sure its full before turning it on. Dishwashers use significantly less water than hand washing.
  3. Use buckets to catch rainwater for filling pet water bowls, but don’t let water sit for days on end as it can attract bacteria.
  4. You can connect a Greywater hose to your washing machine water outlet to direct wastewater onto your lawn and garden.
  5. Only do full laundry loads and use cold water to use less energy.
  6. Turn taps off in between uses ie. Brushing teeth, shaving and conditioning hair in the shower.

Be sure to use cleaning products which are as natural as possible and most importantly are low in sodium as highly salty water can be a big problem for plants and soils.

1 Lenntech, What happens when detergents get into freshwater ecosystems?

2 ABC Gardening Australia, Greywater

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