Grey water is the water which comes from your sink, basin, bath or shower, from dishwashers and washing machines. If you do not use any harmful cleaning products etc. then this water can often be used in the garden.
With the right filtration, it can often make sense to use this water rather than simply letting it wash away down your drains. Typically, grey water accounts for between 50-80% of a household’s water use. So it makes sense not to waste it. Recycling grey water in the right way can save around 70 litres of drinking water per person per day in typical homes.
In the UK, we sometimes feel that there is too much rainfall rather than too little. But fresh water is still a precious resource. It takes energy and resources to treat it. And we can all play our part in creating a more sustainable future by using it more wisely. In addition to harvesting rainwater where we live, we should all think about how we might be able to use grey water to our advantage.
Whether or not water is in short supply where you live, it can be a sustainable way to make the most of resources. And if you have metered water, recycling grey water could save you a lot of money too. Grey water can never be safe to drink, even when treated. But you can use it to flush toilets perhaps, and can also often use it to water your plants.
Making Sure Grey Water is Fit to Use
If you decide that making use of grey water could be a good idea where you live, then the first step will be making sure you don’t use anything harmful in your personal or household cleaning routine.
Unfortunately, many of the cleaning products currently on the market can pose a threat to natural environments. So of course, you should avoid using these products entirely if you want to live in a green and eco-friendly way.
If you want to use this water on plants, you will also need to make sure cleaning products do not contain things like salt, boron, or chlorine bleach, which can have a detrimental effect on plants. And should take care over using products that can excessively alter pH, and could pose a problem when used with certain plants.
Choose natural soaps and cleaning products, and water filtration will be a lot easier and more straightforward. You won’t waste water and will be able to make use of it in your garden.
Collecting Grey Water
Of course, if you do want to make use of grey water in your garden, you will need to collect it first. You will need to take steps to make sure it does not disappear down the drain. Or redirect drainage to collection tanks or filtration points.
The easiest and most straightforward way to collect grey water is simply to use plugs. And to collect water manually in a bucket or other container. This water can be taken right away, and used directly to water trees, shrubs, perennial plants or other any plants not for human consumption. You must use this water right away, as otherwise harmful pathogens may multiply.
If you decide to, you can also redirect drainage to take grey water to a barrel, butt or tank. This could be directly connected to the drainage of the grey water collection points. Some people also redirect grey water for use within the home – flushing toilets, for example, or washing clothes.
Where the grey water does not contain food debris, it can be put through a simple filter of sand, gravel, soil, charcoal etc..Different layers in this type of filtration system have different goals – removing larger debris, and removing various impurities from the water. Again, this is not usually suitable for use on food crops. But grey water treated in this way can be useful in other parts of your garden.
Another option is to send grey water to a reed bed system – a wetland which allows for biological filtration. Bacteria and plants within these systems help to remove impurities and filter the water, which can then be directed elsewhere for use in the garden.
Where food waste is in grey water, woodchip biofilters are sometimes used before water is sent to a reed bed or wetland system. This is a box filled with woodchips with a drain at the bottom that is used to filter out grease and food debris from a kitchen sink. A mulch basin is more or less the same thing, but on a larger scale. It is lower maintenance than a smaller woodchip filter, where the woodchips must be regularly replaced.
Systems vary from the very simple, to far more complex filtration systems that can cost a lot of money. The type of system you will need will depend on where and how exactly you would like to use the grey water in your garden.
It is important to make sure that health and safety is taken into account. It can be perfectly safe and healthy to use grey water in your garden. But only when it is managed and filtered in the right way.
Using it in the Garden
Once you have properly filtered, and as long as you have not sent anything harmful down your drains, you can use it in a number of ways in your garden. Including, potentially, where proper filtration methods have been applied, on edible crops.
Properly filtered grey water can be send to a rain garden type planting area. There, plants and micro-organisms in the soil will continue to purify it. Or you can collect it and use it more widely through your garden. It can be used through watering systems to irrigate garden plants. Once your grey water makes it to the soil, it can be taken up by plants. And limit the amount of other additional water that must be used for irrigation in dry areas. Or during periods of drought.
If you are conscious about the need to live in a more sustainable and eco-friendly way. Then you should take whatever steps you can to conserve fresh water. And recycling water in your garden is one more thing to consider when trying to reach that goal.
Even if you just save a few buckets of water to use on non-edible plants every now and then. This could be a small step in the right direction. But setting up the right system for grey water management can pay dividends over the years to come. So it is definitely something to consider.
Do you have a grey water system where you live? Are you thinking about getting one set up? Share your own experiences, tips or suggestions in the comments below.
Elizabeth Waddington is a writer and green living consultant living in Scotland. Permaculture and sustainability are at the heart of everything she does, from designing gardens and farms around the world, to inspiring and facilitating positive change for small companies and individuals.
She also works on her own property, where she grows fruit and vegetables, keeps chickens and is working on the eco-renovation of an old stone barn.
To get in touch, visit https://ewspconsultancy.com.