‘Odours’ in Oshawa and Durham Region drinking water an annual late summer issue

‘Seasonal biological changes’ in Lake Ontario are the culprits behind the strange odour some residents have been noticing in their drinking water this summer, according to the Region of Durham’s Health Department.

Oshawa Councillor Rick Kerr said he had been hearing some complaints from residents about an ‘odour’ in their drinking water so he reached out to staff at the Region. The changes to the taste and smell of the drinking water happens every summer, he was told.

These episodes typically occur in the late summer to early fall and may cause a musty/earthy taste or odour, regional staff explained.

“Taste and odour episodes are caused by seasonal biological changes in Lake Ontario and Lake Simcoe which produces Geosmin and 2-Methylisoborneol. These are naturally occurring compounds in lakes that do not impact the safety of the drinking water but can be detected in very small concentrations. Many municipalities that get their drinking water from surface water sources will experience the same issue.”

“The Region’s sampling and testing program confirms that our municipal drinking water meets all standards set by the Ontario Ministry of the Environment, Conservation and Parks. The Region’s water supply remains safe to drink.”

The response declared it is “difficult to predict” when conditions will return to normal, but taste and odour episodes generally fade away after the temperature of the lake decreases.

To reduce the taste and odour in the drinking water residents can refrigerate a jug of water, or add ice cubes and a few drops of lemon juice to the water.

For more information about the municipal water supply systems in Durham Region, visit durham.ca/water. Water Quality Reports are also available online at durham.ca.