'Earthy' taste to Calgary tap water caused by harmless compound geosmin, city says

·2 min read

Calgarians have taken to social media to voice their concerns with the scent and taste of the city's tap water.

Most of the people noticing the "earthy" flavour are living in the city's northwest.

Reddit and Twitter are the main outlets for concern, with complaints that the water smells like a fish tank or a swamp, and that it tastes like dirt.

But the city says Calgary's tap water is safe to drink.

Calgary is experiencing elevated levels of a compound called geosmin in its "source water" at the Bearspaw Reservoir, according to a spokesperson for the city.

"The City of Calgary is currently experiencing elevated levels of geosmin in our source water," a city spokesperson told CBC News by email. "Geosmin is a compound produced by algae, bacteria and fungus commonly found in surface water. This odorous substance is released during the natural seasonal die-off of these organisms."

City of Calgary
City of Calgary

The city says geosmin is not harmful, and that staff are constantly monitoring and testing the water supply.

The source water is coming from the Bearspaw Reservoir, which was created in the 1950s following the construction of the Bearspaw dam on the Bow River. Located on the city's western boundary, it provides 60 to 65 per cent of Calgary's drinking water.

The good news? The unpleasant smell and earthy flavour will go away as the cooler weather prevails and the water in local rivers and reservoirs gets colder.

"Our rivers and reservoirs are living environments, and natural occurrences such as spring run-off or algae growth in warm weather are expected," the spokesperson said. "These occurrences can temporarily affect the taste and odour of water but do not impact the quality of drinking water."

In the meantime, the city suggests using an activated charcoal filter, like those made by Brita, which helps to absorb the smell and taste.

With files from the Calgary Eyeopener.