With water rationing in full effect, a UCT expert warns there is a greater chance of contamination as a result of pipes being emptied. Picture: Ross Jansen

Cape Town - With water rationing in full effect, a UCT expert warns there is a greater chance of discolouration and contamination as a result of water being shut down and pipes emptied.

“Even though water treatment cleans water very well, there remain very small particles in the water that settle out in the pipes with low-flow velocities, such as dead-end pipes,” said Professor Kobus van Zyl, of UCT’s department of civil engineering.

“There are also particles that come from inside the pipe itself to add to this." When pipes are emptied and then filled again, he explained that the settled particles are “suspended, creating discoloured water”.

There is also the possibility that ground water, which he said could possibly be contaminated, as well as soil particles, entered the water system “through leak openings when the pipes are emptied”. This does not happen when the pipe is under pressure.

“My recommendation is to use home filtration systems or boil water used for drinking after a water interruption event has occurred.”

Mayor Patricia de Lille has confirmed that changes to the “bulk water distribution system could intermittently impact on clarity or taste within various areas of the city ... in addition, water pressure is being reduced in the water distribution system in order to limit water leaks from underground pipes and faulty plumbing fittings.

“Resultant flow changes in some of the water pipelines may temporarily cause cloudiness or a slight discolouration in the water. Residents with sensitive palates may also notice a slight change in the taste of their water.”

Low levels of geosmin in dam water could also affect the taste of the drinking water, she explained.

“Water consumers in several parts of the city may also have experienced an earthy taste and odour to their drinking water, caused by low levels of geosmin in dam waters. 

"The city would like to reassure residents that this is a naturally occurring compound and is neither toxic nor harmful to health. Water quality is monitored continuously and all water supplied will be entirely safe for human consumption.”

She assured residents and visitors that the city was working hard to reduce the effects of geosmin on the drinking water.

“We advise residents to keep the discoloured water, which initially flows from their taps in these cases, and to please not waste it. This water can be reused for flushing toilets.”

With concerns of water running out in the province and the city, as well as the worry over the quality of the tap water, Priscilla Urquhart, spokesperson for Coca-Cola Peninsula Beverages, which bottles Valpre and Bonaqua, said that bottled water pricing has become very competitive since the onset of the drought.

“We expect the sales of bottled water to continue growing over the next few months, due to continued drought conditions. As concerns have been raised about the quality of the municipal drinking water, CCPB has seen an increase in demand for its bottled water ... that is sourced and bottled outside the Western Cape.”

She said they are prepared for the demand for bottled water to increase and are in communication with their bottling partners outside the Western Cape, “should the water situation worsen in the province and impact our production capability across the other brands we produce”.

“To reiterate, our non-flavoured bottled water brands Valpre and Bonaqua are brought in from the sources outside the Western Cape. This is an important consideration for consumers to know that the water they are purchasing is not putting a further strain on dwindling local water sources.

"Local bottling water sources are expected to be running dry in the coming months, depending on the levels and capacity. As we are bringing our bottled water from outside the Western Cape, we do not expect shortages on our branded bottled water,” said Urquhart.

Weekend Argus