Chemical compound found in Cape Town tap water: Is it safe to consume?

Tap water in Cape Town tasting ‘earthy’

If you live in Cape Town and sipped on a glass of tap water recently, you may have found the taste of it a little ‘different’.

This, according to the City of Cape Town, is due to the presence of an organic chemical compound found in the water.

Residents have reportedly experienced an ‘earthy’ or ‘sandy’ taste and smell while drinking tap water, because if a naturally occuring compound called Geosmin.

And while the taste may be weird, the City has affirmed that the tap water is still safe to drink and remains compliant with South African Drinking Water Quality Standards (SANS 241: 2015).

What is Geosmin?

The City said 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 compound is present in water at undetectable levels, but during periods of hot weather, which the City just experienced, the levels of geosmin can increase and even tiny concentrations of a few parts per trillion can be detected by the human palate.

The City’s Water and Sanitation Directorate revealed that Geosmin is currently affecting the taste and smell of the water supplied from the Faure and Blackheath Water Treatment Plants (WTPs) to various areas across Cape Town, primarily the central and southern areas.

“I’d like to assure residents that the City’s engineers, lab scientists and process controllers are closely monitoring this situation. The water teams at Faure and Blackheath WTPs have also boosted their already rigorous water treatment process, by dosing powdered activated carbon to reduce the effect of the geosmin.” the City’s Mayoral Committee Member for Water and Sanitation, Councillor Zahid Badroodien, said.

The Councillor added that it may take some time for the taste and smell of the water to normalise.