Tap Water - musty odour or taste

  1. If only one tap in the house with a taste and odour problem (rotten egg, sewage, foul, bad smell), this indicates a possible drain problem, not a taste and odour in the water issue. Please do the following:
    1. Fill a glass with cold water and move away from the drain/sink, preferably to the bedroom or living room and see if you still detect the odour in the water.
    2. If the taste and odour is not detected in your glass of water, the issue is most likely related to a drain problem. In order to reduce the drain issues, the drain can be disinfected using the following the steps:
      1. Remove the aerator from the tap in question and flush well to remove any debris. Re-install the aerator. (A faucet aerator (or tap aerator) is often found at the tip of modern indoor water faucets. Aerators can be simply screwed onto the faucet head, creating a no-splashing stream and often delivering a mixture of water and air.)
      2. Flush the cold water tap for one (1) minute, then turn off the tap
      3. Pour one (1) cup of household laundry bleach down the drain. Do not use any other product. Let it sit undisturbed for 10 minutes. It is vital that nothing else except the bleach is poured down the drain during this time.
      4. After 10 minutes, turn on the cold water for five (5) minutes to thoroughly flush the drain.  
    3. If, following the disinfection instructions, there is no longer any odour, flush the remaining taps in the house. The issue will be resolved and no further action is required.  
    4. If, after following the disinfection instructions, the taste and odour still remains, contact Toronto Water Laboratory staff at the Water Quality Line for further assistance.
  2. If the odour is coming from the cold water tap and is noticeable from all taps in your home:
    1. check the floor drain in the basement. Make sure there is water visible in the drain. If no water is visible, pour a bucket of water down the drain. The water prevents sewer gases from backing up in your home through the drains. If the odour persists after doing this, contact staff at the Water Quality Line.
  3. If the water coming from every tap in the house has a "earthy/musty odour": Occasionally during the late Summer and early Fall months, the presence of naturally-occurring algae and higher water temperatures in Lake Ontario can cause a noticeable taste and odour in tap water. The water remains safe to drink during these events. If residents notice their tap water has an earthy, musty taste or odour, keeping a jug of water in the fridge and adding ice cubes or lemon juice to your tap water should improve it.