The City of Cape Town has reassured residents who have detected an "earthy" flavour to their tap water that it remains safe to drink.
On Thursday, the City said the water was safe to drink and compliant with SANS241 standards.
"It must be emphasised that geosmin poses no threat to human health. It is a naturally occurring organic compound and is responsible for the earthy taste of beetroot and the scent that occurs in the air when rain falls after a dry spell," the City said in a statement.
The compound was sometimes present in water, particularly during periods of hot weather, and even minute concentrations of a few parts per trillion could be detected by the human palate.
The City said there were currently high levels of geosmin in the raw water supply from the Theewaterskloof Dam.
This was affecting the taste and smell of the water supplied from the Faure and Blackheath water treatment plants to various areas across Cape Town, primarily the central and southern regions.
"The City is monitoring the situation as part of the water treatment process, which is currently enhanced by the dosing of powdered activated carbon during this process to reduce the effect of the geosmin."
However, it may take some time for the taste and smell of the water to normalise.