Grey Water
By Sipho McDermott

The average middle class household in South Africa uses up to 200 litres of water per person per day to water their garden. This statistic, supplied by Biolytix, a water recycling company, shows how expensive it can be to use fresh water for your garden. It also shows the impact that such households have on the already stretched national grid, which in turn leads to fewer people having access to clean water for their basic human needs. The wider impact is also noticeable in that more strain is placed on the national supply chain to provide foods that could be grown in your household; this in turn leads to greater levels of pollution. This consumption of fresh water is not necessary when the solution is rather simple and lies in recycling the water that you already use in your household.

This recycling produces slightly used, or grey water. According to Tsogang Water and Sanitation, an NGO that specialises in water provision, grey water is any water that has been used in the household, besides that from toilets. The water is not deemed healthy or clean enough for human consumption but can be used to irrigate plants. In your household all you have to do is tinker with the plumbing so that the water from your main taps and shower feed into an irrigation channel that then flows into a water tank to settle, and then into your food garden. This can provide for all your garden needs as one washing machine cycle uses 100 litres of water and a shower uses 22 litres per minute. It is important to note that you should not spray this water onto the garden since the water needs to enter from the roots and not pollute above the surface.
The benefits of grey water are even greater in areas where people have intermittent access to clean water and may not even get the 25 litres per day deemed to be necessary for sustaining a healthy lifestyle. Here the water can mean the difference between a food garden succeeding or it failing and malnutrition setting in. NGOs are increasingly using grey water in communities that have limited access to water, to great success.

Although grey water is a relatively clean source of water, it is important to ensure that you do not add too many chemicals to your water otherwise the plants can suffer. It is therefore advisable to use biodegradable washing materials in washing machines and sinks. In the kitchen sink it is also advisable to get a device, called a ‘fat trap’, which catches and filters out excess fat so it does not choke the plants in fatty deposits.

More advanced systems, involving utilising rainwater tanks to mix clean and grey water are also easy to set up and maintain. Although the system will require an initial investment of money and labour the result is worth it. Thanks to grey water and this recycling you will be able to grow a garden so you can feed your family healthy food for free and give the planet a needed breather.