Drinking water - Taste, odour and appearance

Why does my water smell musty or have an unusual odour?

If the musty odours occurs only at one faucet, the odour is related to something at or near the faucet.

Try cleaning the drain, this often removes the odours. Please note unusual tastes or odours are aesthetic in nature and do not pose a health risk.

In Calgary, our source water can experience elevated levels of geosmin, a harmless, naturally occurring compound, in the water in the late summer and early fall.  This can produce a temporary, earthy or musty change to the taste and odour of your water, but it remains safe to drink and continues to meet all guidelines set by provincial and federal health standards. 

Geosmin is harmless and does not require further treatment from a health standpoint, but the human nose is extremely sensitive to geosmin, which can be detected by some people at very low levels (as low as 5 parts per trillion). If you’re sensitive to the changes, we recommend keeping a pitcher of water with lemon slices in the fridge or using an activated charcoal filter (e.g. Brita filter) that will help absorb the geosmin, which affects the smell and taste.

Any differences in taste and odour will generally diminish into the fall as concentration levels of geosmin decrease in the source waters.

What should I do if my water tastes stale?

Drinking water may taste stale if faucets have not been used recently. Running the cold water tap briefly will allow fresh water from the water main to your tap.

My water has a milky or cloudy appearance. Should I be concerned?

Air bubbles in water may cause a milky or cloudy appearance, especially in cold water. These bubbles pose no health risk.

Cloudiness appears more often in the winter, when the water is cold. Allowing water to sit will let the air dissipate and the water will clear.

Why does my water have a yellow or rusty colour?

Watermain repairs, construction and other work in your area can cause some rust and sediment, which normally stick to the inside of the water main, to break away. Fire hydrant flushing can also cause this inconvenience.

The discoloured water is safe to drink, but may cause water to appear dirty. If this happens, run your bathtub tap on cold for 30 minutes until water clears and then run other cold water taps for five minutes or until clear.

Should I be concerned if my water has a chlorine taste or smell?

We add chlorine to disinfect your water and keep it free from harmful microorganisms. Some conditions, such as spring runoff, affect the quality of the water supply entering Calgary from the Bow and Elbow Rivers.

During these times, we adjust water treatment, which may include increasing the level of disinfectant, to ensure that your drinking water remains safe.

You may notice an increase in the taste and smell of chlorine in your drinking water. To remove the taste and smell of chlorine, fill a container of water and keep it in the fridge for drinking. Much of the chlorine will dissipate from the water overnight.