Johannesburg Water has confirmed that an earthy compound called geosmin has been detected in the drinking water supplied to residents of the City of Johannesburg however the substance is not harmful to human health.

In a statement released on Monday the utility said it was notified of the substance from its bulk drinking water supplier Rand Water.

According to Johannesburg Water the substance is often accompanied by a taste and odour which will sometimes manifest itself in the potable water supply.

“The substances causing these odours are not harmful to human health. The problem occurs infrequently and is usually of short duration,” the utility explained

“During warm periods raw water sources, in this case the Vaal Dam, may experience blue green algae which result in unwelcome taste and odour constituents in the drinking water. Consumers may detect an intermittent earthy or musty taste due to this presence of geosmin,” it said.

The utility noted that taste and odour problems were not unique to Rand Water’s area of supply but are experienced world-wide.

It added that it is committed to providing water and sanitation services that are of high quality to all residents and that it will continue to run tests to ensure the health of residents is not compromised.