#ISaveWater – Now’s the time to learn more about grey water recycling

South Africa is a water scarce country, and has been ranked the 30th driest nation on Earth. If the worrying forecasts made by #ClimateChange researchers are in any way correct, future rainfall patterns will become increasingly erratic – which, in turn, means that we will experience uncertain conditions with regards to our water supply.

Grey water recycling, simply put, is something we all need to be doing.

What is grey water?

  • Consumption quality drinking water that we obtain from our municipalities is known as “potable water” (most often), but is also sometimes referred to as “white water”.
  • By contrast, water with very high organic loads – generally meaning a high bacteria load – is referred to as black water. The most common source of black water is our toilets; but it is also best to consider, for example, water used for washing nappies as black water, too.
  • Grey water is not potable water, but has a much lower organic load than black water, and is suitable for garden irrigation (as long as laws and best practices are followed). If the grey water is of a high enough quality, it could also be used for flushing toilets.

Showers, baths and bathroom basins are great sources of safe grey water

What are the best sources for grey water?

There is widespread agreement that the best sources for grey water are showers, baths and bathroom basins. If you aren’t using your washing machine for items with high bacteria loads (e.g. nappies) or with high grease, food stuff and fat content, it may also be a source. Dishwashers and kitchen sinks are slightly more controversial, though, as their wastewater does contain fat, grease, oil, foodstuffs and even, possibly, pesticides.

Regarding kitchen sinks and dishwashers, however, systems have been designed to trap the unwanted loads in order to maximise a household’s grey water sources. But, for now, these may best be left to more experienced recyclers.

Some of the basics

Whereas harvested rainwater stored in a Jojo Tank has a long lifespan – so long as your area of catchment (roofs mostly) is kept clean of leaf debris and pollution – the fact that grey water does have some organic load shortens the time it can be stored. A maximum of 24 hours is the gold standard.

To understand why, it is important to know that water which has been heated, in a geyser for example, loses some of its oxygen content. When stored, this leads to anaerobic bacteria growth and the release of sulphide gases – creating not only a foul odour, but the potential for harmful bacteria to enter into your garden. Pumps that re-oxygenate the water and additives that promote the growth of benign bacteria are available, but, again, this should be left to the more experienced.

Eco-friendly soaps avoid salts that are harmful to plants

The best use for grey water

Considering that many households use a significant amount of their monthly water consumption in the garden, grey water is a great way to reduce this. The idea is relatively simple: direct grey water from your shower, bath and bathroom basin into an appropriate tank, which then, either under the force of gravity or a low pressure pump, is fed into a drip irrigation system.

It should also be noted that grey water, as long as chemicals like bleach are excluded, can have very beneficial effects on plants as it provides nutrients like nitrogen and potassium to the soil.

Builders stocks all your irrigation requirements, including drip irrigation kits and LDPE piping.

Legal and health considerations

Current legislation doesn’t refer directly to the use of grey water, but correct practices can be inferred from the National Water Act (No. 36 of 1998) and the National Health Act (No. 61 of 2003). Some of the most important considerations are:

  • Grey water may not be the source of foul odours; therefore stick to the 24-hour rule
  • No black water may be allowed to mix with stored grey water
  • Grey water should not be used in sprinkler systems as this could, in the event that harmful bacteria and viruses have infiltrated the water, spread harmful pathogens through the air
  • Grey water is to be used as drip irrigation
  • Tanks must have an overflow into the sewerage system
  • Grey water may not form pools on your property
  • Grey water must be kept on your property and not flow into neighbouring areas or the street
  • Keep skin contact with grey water to a minimum, and keep children away from playing in areas that are still wet

The fact of the matter is that grey water, handled properly, is one of the best ways to reduce your water demand while still keeping your beautiful garden flourishing and healthy. For all your grey water needs, speak to the friendly staff at your nearest Builders or shop online here.

Happy and safe recycling!

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