As a precautionary measure, the City of Cape Town would like to advise residents in St Michaels, Brackenfell of poor water quality due to the possible ingress of sub-standard water from stagnant, previously isolated sections of the pipeline.
As such, residents are informed that it may be unsafe to use water for drinking, washing, cooking, brushing of teeth, etc. unless it is boiled. The following steps must be followed to ensure that the water is safe:
· Heat water to boiling point and maintain at boiling point for at least one minute
· If water cannot be boiled, chemical disinfection should be used. Unperfumed common household bleach (sodium hypochlorite) contains a chlorine compound that will disinfect water. Add at least two drops of liquid bleach per litre of water (four drops if the water is cloudy). Stir or shake well and let it stand for 30 minutes before use. If no smell or taste of chlorine can be detected at that point, add another dose and wait another 15 minutes before use
· Chlorine tablets containing the required dosage for drinking water disinfection can be obtained from a chemist or supermarket and should be applied as per instructions on the labelThree water main bursts have occurred in the vicinity of the Brackenfell Railway Station and in Old Paarl Road, Brackenfell since Sunday morning, 20 November 2016. These bursts necessitated flow reversals in the system and, as a result of these reversals, poor quality water from stagnant sections of the pipeline was drawn into the supply lines. Poor water quality is not due to the ingress of sewage into the reticulation system, as has been suggested on various social media and community platforms. The low levels of ammonia in samples taken are not consistent with this claim.
The City’s Water and Sanitation Department first received complaints of water quality on Wednesday 23 November 2016, and the reticulation system has been flushed within the vicinity of these complaints. A broken valve in the closed position was replaced to improve flushing and circulation within the system. However, laboratory results from City Scientific Services Branch received this morning have confirmed that there are still pockets of water in the system that do not comply with the Drinking Water Standards (SANS 241: 2015).
The City is carrying out continual water sampling, testing, flushing and chlorination processes until the water meets the required standards. Consumers will be updated on the status of the water supply in St Michaels, Brackenfell, and staff will today perform a letter drop to affected customers.
The City would like to emphasise that the water quality issues described above are limited to the St Michaels area where the water mains bursts occurred. The City has also been experiencing issues with water taste and odour from the Blackheath and Faure water treatment plants (which receive raw water from Theewaterskloof Dam) due to the presence of geosmin in the water, and as such residents in the greater Brackenfell area and surrounds may also notice a difference in their drinking water supply. These residents are assured, however, that geosmin is a naturally occurring compound found in surface waters (rivers and dams) as an organic molecule produced by kinds of algae and bacteria. This compound is responsible for the earthy, musty taste and odour sometimes found in the water and does not pose a health risk.
Geosmin is removed using powdered activated carbon in the water treatment process, however even minute concentrations can still have an effect on taste and smell due to the incredible sensitivity of the human palate to the compound. A recent sample of the water in the area showed a geosmin concentration of a mere 3,4 nanograms (1 thousand-millionth of a gram) per litre.