Greywater – your secret source


A greywater system in a suburb – five steps to a beautiful garden

‘First plant indigenous, water-wise plants as much as possible,’ says home-owner Angie Thomson. ‘Then with the greywater system it’s enough to keep things alive, even during the drought.’ Photos: Sue Maclennan

The moveable sprinkler on a stand that Thomson has rigged up and connected to the greywater tank.

An underground tank operates on a float-level system. It’s permanently connected to a moveable hosepipe and a stand with a sprinkler fixed to the top. When the tank fills up, the sprinkler automatically starts. This way, the water doesn’t remain in the tank for too long. ‘Although we do have to clean the residue out periodically,’ says Thomson. ‘Because the water is soapy, it settles on the bottom and the sides.’

Wastewater from the kitchen, handbasin and shower is diverted from outlets through pipes that run below the ground away from the house.

Whether your garden is your green haven for relaxing in, the place to grow food for your family – or both – water restrictions mean you can’t water your flower beds or vegetable patch with a hosepipe. And as drought conditions in South Africa persist, and dams empty, it will become unthinkable to use drinking water for flushing toilets, watering gardens and washing clothes.

People in Grahamstown and on the farms around us are discovering the health and economic benefits of subsistence farming, but water remains the key to growing enough food, consistently, to sustain families and communities.

We have to find new sources of water. Using greywater in small-scale farming and in gardens is one way of alleviating water stress.

Greywater, according to a study commissioned by the Water Research Commission, is “untreated household effluent from baths, showers, kitchen and hand wash basins, and laundry (i.e. all non-toilet uses)”.

They found that “Active promotion of greywater use for irrigation in gardens and small-scale agriculture has the potential not only to maximise use of limited water supplies, but also to improve food security in low income settlements.”

The study into the use of greywater is intended to be used by municipalities or NGOs wanting to start greywater irrigation and members of the public wanting to use it on their properties. The researchers estimate that more than half of indoor household water – 50% to 80% that is used for washing could be intercepted by the householder for additional beneficial uses.

In addition to saving our precious water resources, the benefits of using greywater in your garden or on your vegetable plot include that greywater contains nitrogen and phosphorus – chemicals put into costly fertiliser to enhance growth. The soapiness in greywater is also good for pest control.

But there are also risks. You should know what they are and how to deal with them.

These include becoming ill from handling the greywater or using produce irrigated by greywater; reduced growth or yield of plants irrigated with greywater; and environmental degradation – soil irrigated with greywater has a reduced ability to support plant growth.

Removing greywater from sewage infrastructure also increases the potential for blockages, according to the researchers. And in informal settlements, or parts of Grahamstown where blockages mean sewage overflows into people’s yards, the greywater mixture can be toxic.

Greywater left to stand also gets smelly and is a great place for bugs to breed.

“Greywater intended for irrigation use must be limited in terms of the number of uses within the household prior to use for irrigation and must be isolated at source,” the researchers say. “Greywater which has been used multiple times or which is collected after discharge into the environment should not be considered as suitable for irrigation use.”

If you don’t have the facilities to have your greywater tested and analysed, the Water Research Commission recommends:
* Wash hands and arms well with soap after handling greywater.
* Use bathwater water and laundry rinse water only.
* Use all greywater within 24 hours of collection.
* Grow only non-food plants or food plants that will be cooked before consumption.
* Use irrigation methods that minimise contact of greywater with aboveground plant parts.
* If using on lawns, avoid direct human contact for 8 hours after irrigation.
* If using on crops, stop irrigating with greywater two weeks before harvesting.
* Reduce volume of greywater per application if ponding occurs on surface of irrigated ground, or if water runs off the surface.
* Wash all crops well in soapy water after harvest and dry in sunlight.
* Peel and cook crops prior to consumption.
* Do not use greywater that has not been tested for any form of communal gardening.
* Do not use greywater if someone in the household has an infectious disease.

* Use bathwater water and laundry rinse water only.
* Increase greywater application or alternate with freshwater, in order to leach out salts, if plants show symptoms of salt stress.
* Apply agricultural gypsum and compost to ameliorate soils if infiltration rate decreases and it is suspected that this is related to high sodium content of greywater.

* Do not irrigate with kitchen greywater or with laundry greywater except rinse water.
* Do not use greywater that’s untested if the soil is very clayey, if the ground has a steep slope, or if the irrigation site is close to a river or borehole.
* Do not use greywater if the irrigated land is close to sensitive environments which may be adversely affected by greywater runoff or infiltration, e.g. high water table, wetlands.


The best way to use greywater on plants

Apply the water as close as possible to the root zone of the plant, preferably below the surface of the soil. This avoids contact of the leaves or fruit with micro-organisms which may cause health effects and with greywater constituents which can be absorbed through the leaves.


Ways to treat greywater:

  • Filtration e.g. through fabric or geotextile, is a first step to improving the quality of greywater.
  • Mulch towers remove suspended solids, oil and grease through filter beds comprising different sizes of gravel and sand.
  • SOURCE: Sustainable use of greywater in small-scale agriculture and gardens in South Africa: Guidance report by Nicola Rodda, Kirsty Carden and Neil Armitage – Report to the Water Research Commission by School of Biological and Conservation Sciences UKZN and Department of Civil Engineering UCT (December 2010). The full report and details are here:



We’d love to hear how you re-use water in your home to save our dams (and your water bill!). Email your tips to or whatsapp to 076 733 1770


Where can you buy a water tank in Grahamstown?

Business Name Name of the Tank Size of the tank Price / Amount Contact Details
Build It Jojo Tank 2 500 litres R 2 200 046 622 3086
5 000 litres R 4 200 046 622 3086


Business Name Name of the Tank Size of the Tank Price / Amount Contact Details
Cash Build Eco Tank 2 500 litres R 2 280 046 636 8900
5 000 litres R 4 030 046 636 8900


Business Name   Name of the Tank    Size of the Tank     Price / Amount Contact Details   
Buco Jojo 2 500 litres R 2 506.25 Vat excl 046 622 7301
5 000 litres R 4 412.40 Vat Excl 046 622 7301


Who can install rainwater tanks and/ or greywater management systems at your home?

Following a call by the GRA on its mailing list and Facebook page for names of companies able to install tanks and pumps suitable for water harvesting and greywater systems respectively, the following were put forward. The GRA said they had not contacted any yet. “It is up to customers to decide whether they are reliable etc.,” the GRA said. 

4J’s Water           
Jacobus van Jaarsveld       
073 312 8766

Peri Maintenance    
081 339 1173

Davies Plumbers    
Richard Davies                   
082 932 6006

Coetzee Plumbing  
Andrew Coetzee                 
084 290 0370

Albany Pumps
Hill Street                                       

046 622 8822

Green Overall (PE)
082 771 2062/ 087 086 3020

  • Source: Grahamstown Residents Association
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