Where does Cape Town’s water come from?

Cape Town’s tap water comes from Mountain Rivers and Streams, mostly from the surrounding Drakenstein and Franschhoek mountains. Theewaterskloof Dam near Franschhoek is Cape Town’s primary water source, supplemented by water from the Table Mountain dams, Steenbras upper and lower dams, Wemmershoek Dam, and Voelvlei Dam.

What makes water unsafe to drink?

Water is unsafe if it contains harmful micro-organisms, or substances in large enough concentrations that make it dangerous to drink. These must be removed from water (treated) to make the water safe.

What Standards are in place to ensure the quality of drinking water in Cape Town?

Complying with international standards, the South African National Standards for Drinking-Water Quality (SANS 241: 2006) is the recognised legal standard for drinking water quality across South Africa and details the required parameters for drinking-water quality in South Africa.

What programmes are in place to ensure the quality of Cape Town’s water?

The City of Cape Towns Environmental Health Section implements a Potable Water Quality and Safety Programme that is designed to monitor, evaluate and control the quality of potable water supplied to the citizens of Cape Town. The aim is to ensure that the potable water supply poses no threat to human health and complies with the South African National Standards for Drinking-Water Quality (SANS 241:2006).

What is the Blue Drop programme and what does Blue Drop certification entail?

The ‘Blue Drop’ programme is a national programme designed to monitor, evaluate and report on the drinking-water quality in municipalities across South Africa, as well as on the quality of the management systems and processes in operation to ensure the quality of drinking-water in these municipalities. The programme was launched by the National Ministry of Water and Environmental Affairs in September 2008. South African municipalities who achieve full compliance on an annual basis with SANS 241:2006 are awarded ‘Blue Drop Status’. The City of Cape Town is a certified Blue Drop Status City for 2010, having achieved outstanding compliance results for the quality of its drinking-water since the inception of the programme in September 2008.

Blue Drop certification not only recognises a municipality's ability to provide quality drinking-water to residents and visitors, but also gives recognition to the efficiency of the entire process surrounding the purification and distribution of drinking-water. The Blue Drop certification process sources and records data taken from consistent sampling over a three-month period, and evaluates these results against the SANS 241:2006. In order to qualify for Blue Drop Status, a total score of 95% compliance must be achieved across all evaluation criteria, with a score of 97% required for microbiological compliance.

Additionally, the City received Blue Drop Status certification for drinking water in the following areas:

• Certificate for the entire Cape Peninsula
• Certificate for Drakenstein Local Municipality (Paarl Mountain water supply)
• Certificate for Stellenbosch Local Municipality (Paradyskloof system)
• Certificate for Stellenbosch Local Municipality (Franschhoek system)
  

What is Cape Town’s water tested for?

• Physical and general: conductivity, turbidity, colour
• Organic: oxygen absorbed, hardness, alkalinity
• Minerals: chloride, sulphate, calcium, magnesium, sodium, potassium
• Trace metals: cadmium, cobalt, chromium, copper, nickel, lead, vanadium, zinc, aluminium, iron, manganese, nitrogen
  
• Other in-organics: silicate, total phosphorous, fluoride, total dissolved solids
  
• Microbiological: e.coli
  

Where is the water tested?

Water is tested at the City of Cape Town’s Scientific Services Unit, based in Athlone. The Unit consists of state-of-the-art testing equipment, technicians and scientists, trolley-loads of water samples, and a perfected sample-logging system. The South African Bureau of Standards (SABS) checks the lab’s work every month, and Cape Town’s Lab consistently gets top results.

How often is the water tested?

On the path from source to sink, Cape Town’s water is:
1. Tested
2. Stored in a dam
3. Tested
4. Transported to Water Treatment Works,
5. Tested,
6. Treated,
7. Tested,
8. Transported by pipe to our taps.

Additionally, a representative number of water samples are taken every week from different points along the distribution network in the Cape Metropolitan Area, and submitted to the Scientific Services lab for chemical analysis in compliance with SANS 241:2006.

How is the water treated?

1. The water is clarified, to remove suspended material. This is done with coagulants that bind any contaminants; these are then filtered out of the water.
2. If the water is not clear, aluminium sulphates or ferric sulphates are added to remove the colour.
3. Sometimes lime is added for ph control, and carbon-dioxide to stabilise the water and ensure that the transport pipes are not damaged.
4. Chlorine is used to disinfect the water and remove any bacteria.
5. Most of the additions above are removed, although the water is always tested for residual chlorine to ensure bacterial free supply.

Where is the water treated?

At one of the City’s five water treatment sites.