Recycling Water


Water is an extremely precious resource and will only become more so with population increase and climate change effecting the water cycle. There are many ways that you can play your part to lessen the pressure on the water supply by reducing water consumption and reusing water as much as possible. 


Grey water

Grey water is a term given to household and commercial wastewater which comes from showers, baths, basins and washing machines. The average person in Australia produces around 84 L of grey water a day, which is nearly 2/3 of their total wastewater (Your Home, Wastewater reuse). Grey water can be repurposed for irrigation or flushing the toilet. 

There are many ways you can collect and reuse your wastewater to improve sustainability.

There are numerous methods and systems you can use to recycle greywater. You can install a simple diversion device which is basically some flexible hosing going from the water source straight into the garden. This will obviously be easier to do if the source, such as your washing machine, is right next to the garden and you can just feed it through a window or hole in a door (perhaps you have a pet flap).

You can also install a closed loop system which diverts grey water into your toilet rather than your garden, which is very helpful if you live in an apartment, or if your grey water source is far from the garden. However, you will only be recycling around a quarter of your grey water if you do this as the average person uses about 20L/day flushing the toilet. Furthermore, you will have to check with your local authority if this is approved.

You can get grey water storage tanks, to store the water. Water which is not used within 24 hours will require treatment, meaning you will also need to install an additional system for this. These can be quite costly, so would be the choice for those making an environmental decision, rather than an economic one, unless they are not connected to the mains water supply.

This system can redirect greywater to where it is required around the household (Creative Commons).

There is also the option of simply collecting your grey water in buckets or a removable basin. This is much less efficient as you will have to be waiting at the ready when the spin cycle starts on your washing machine. However, it is visually very impactful and really makes you aware of how much wastewater you are generating. Which in turn can motivate you to use less water in the first place.  This technique can be quite fun to get children involved with. Watch the Recycling Water video to see how it can be done.

Using buckets to collect wastewater is time consuming but can be fun.

Irrigation considerations

If you are going to use grey water on your garden, you will need to:

  • “Shandy” the water – this means either mixing it with fresh water or alternating fresh and grey water use.
  • Minimise the use of cleaning products.
  • Use grey water friendly soaps, detergents and washing up liquid.
  • Filter lint in the washing machine.
  • Monitor your plants carefully, some will be more sensitive to grey water than others. Plants that like highly alkaline soils will be hardier.
  • If using dishwater, you may want to sieve it to avoid food waste going into the garden and encouraging pests.


Next Steps:

  • Read more about how to reduce your water waste by reading the blog article Water Cycle and You
  • Try some more related activities from the Y7 WASP STEM Recycling Water Project
  • Have a look at your water bill, as some water bills will show how you compare to other households.  Are you a waterwise household or is there room for improvement?