What to know
- Toronto tap water can develop an earthy or musty smell or taste in late summer and early fall, mainly due to natural algae and warmer temperatures in Lake Ontario.
- The water remains safe to drink, and the city says no extra precautions are needed.
- If you don’t like the taste or smell, try refrigerating the water overnight or adding ice and a slice of fruit.
- A smell or taste coming from just one tap could point to a private plumbing issue, rather than a problem with the city’s water supply.
- Toronto treats its drinking water before it reaches the tap, using multiple filtration and disinfection steps to remove impurities and harmful bacteria.
Drinking a glass of earthy or musty water might feel unpleasant, but it doesn’t mean it isn’t safe to drink, according to the City of Toronto.
Those who’ve lived through Toronto summers might have noticed an earthy or musty smell or taste on their tap water at this time of the year.
As explained by the City of Toronto, this is a common occurrence during late summer or early fall, caused by natural algae and high temperatures in Lake Ontario.
However, when this happens, the water remains safe to drink, with no extra precautions needed.
The city recommends those who are sensitive to the smell or taste to fill in a pitcher with the water and leave it on the fridge overnight, or even add ice and a slice of fruit to the water to reduce it.
Private plumbing issues
Although earthy or musty smell at this time of the year is likely caused by lake conditions, the City of Toronto warns that other factors might also be responsible for altering the tap water aspect.
If only one tap water in the home has a different taste or smell, it might suggest there’s a private plumbing issue. Those who experience this are warned to run the cold water for about 10 minutes, take some of the water and move it to a different location. If the smell is no longer there, the drain might need to be disinfected.
To disinfect the drain, residents can pour a cup of bleach down the drain, leave it for 10 minutes, and then run the cold tap water for five minutes to rinse it. If the smell still persists after that, residents are warned to contact 311 for support.
Why is tap water safe?
In Toronto, the tap water that comes from Lake Ontario is safe to drink, as the city treats it under the requirements of the Ontario Ministry of the Environment, Conservation and Parks (MECP).
The water is collected from the lake through intake pipes and passes through screens to filter out debris. After that, the water is disinfected with chlorine or ozone and a coagulant chemical is added to separate particles in the water together and form a floc.
The water then passes through sand and anthracite or activated carbon filters to remove impurities.
Finally, the city adds chlorine, fluorine, ammonia and phosphate to the water to help destroy bacteria, prevent tooth decay, and reduce the risk of lead entering the water.
