In early March 2024 the residents of Johannesburg, South Africa’s largest city and the economic capital of the country, were hit by extended cuts in water supplies. This was a new low after months of continuous deterioration. Professor in the School of Geography, Archaeology and Environmental Studies at the University of the Witwatersrand Craig Sheridan sets out the risks this poses to drinking water in the city.
What can get into my water that will make me sick?
- You can have chemicals in the water that are toxic, or you can have pathogenic organisms which can make you ill.
- As a general rule, South Africa’s water works are able to remove almost all chemicals such that the water is safe to drink.
- The water treatment works also disinfect the water, killing harmful bacteria and viruses.
Is my tap water safe to drink?
- And if the water has residual chlorine in it, that means the supply to your home is good.
- Unfortunately, this relies on drinking water treatment works functioning properly, which is not always the case.
- The department of water and sanitation runs an auditing process of the water treatment works and the water they supply.
My water supply has been interrupted a lot. Is my tap water safe to drink?
- If there is no water in the pipe, and there is an underground sewage leak near the water pipe, or contaminated storm water near the pipe, there’s a real possibility that contaminated water can enter the pipe.
- As water supply returns, this “first flush” down the pipe has the potential to contain contaminants.
- If your water remains brown or discoloured, report it and drink purified water.
I get my water from a mobile water tanker. Is this safe to drink?
- But there are far too many instances of
unscrupulous, roaming water tanker suppliers selling water, especially in areas with no access to safe tap water.
- Since water supplies have become less dependable, the state has turned to businesses to supply water to communities.
- If this is the case, it is sensible to purify the water.
What are the diseases that make drinking water unsafe? How are they spread?
- When water is sent to a laboratory for testing, the first test is for an organism called Escherichia coli, or E. coli.
- But if it is found in the water, there is absolute certainty that the water has been contaminated with faecal matter which has not been properly treated.
- This is why it is used as a screening tool for more serious diseases which are also spread through faecal matter.
- It is highly contagious and can spread by contact mainly from drinking contaminated water, food or from unwashed hands.
If I store water in bottles, how long before it’s unsafe to drink?
- How warm is the water?
- Water safety cannot be fully assured without analysing the actual water.
- At the Centre of Water Research and Development we are doing research partly funded through the Water Research Commission to develop test strips to give a rapid analysis of drinking water quality that can easily be understood by the general public.
Is purifying water difficult?
At the University of the Witwatersrand we commissioned a short animation in all of South Africa’s 11 official languages as well as French and Portuguese on how to prevent cholera transmission and how to purify your water to ensure you stay safe. We have also shared guidance on how to purify your water to make it safe.
Craig Sheridan receives funding from The Claude Leon Foundation, the Danish International Development Agency (DANIDA), The Water JPI, The BMBF, FORMAS and the Water Research Commission. Craig Sheridan is a member of the South African Institution of Chemical Engineers (SAIChE), the Institute of Chemical Engineers (IChemE), and the International Water Association (IWA).
