Public Notice: Seasonal Changes in Taste and Odour of Tap Water

It is not uncommon for the City of Owen Sound water to experience some short-duration taste and odour issues in late August to early September as Georgian Bay temperatures hit their seasonal peaks. Here is what you should know.

Occasional changes in the taste and odour of drinking water is not a threat to public health

Residents may notice changes in the taste or odour of their drinking water. These changes are often a musty or earthy taste or odour, or a noticeable increase in chlorine's taste or odour. These changes in taste and odours could last from late August into early September.

This is a common occurrence in many Ontario municipalities, such as Owen Sound, which gets its water supply from surface water sources and experiences this problem periodically. While changes in taste and odour may be unpleasant for some with sensitive senses, these changes only affect the water's aesthetic qualities and do not impact its safety.

Causes of taste and odour changes

Taste and odour occurrences are caused by a couple of different factors. One factor is the seasonal biological changes in the source water, which produce odour-causing chemical compounds called geosmin and 2-methylisoborneol. Even very tiny concentrations of these compounds can result in the earthy or musty taste and odour in water.

Standard lab tests detect limits for both compounds at three parts per trillion, but some people can taste or smell them at concentrations of just one part per trillion. Some can notice these changes even when levels are so low they are undetectable by standard testing.

The second factor is changes to drinking water treatment processes in response to changing source water conditions, such as an increase in water temperature, which requires higher levels of chlorination to treat.

During these episodes, tap water supplied by the municipal water supply systems remains safe to drink.

Ways to reduce tastes and odours

Residents who experience taste and odour issues with their tap water can use water pitcher filter systems, such as a Brita, to help reduce or eliminate the tastes and odours. They can also store water in a loosely sealed glass and put the container in the refrigerator for a period before drinking.

For more information, please contact Bryce McDonald, Manager of Water and Wastewater at 519-376-4247 ext. 3224 or email to bmcdonald@owensound.ca