Water Quality FAQs: Taste and odour of water

Why does my water smell and/or taste of chlorine antiseptic or TCP?

Chlorine in drinking water is not harmful. It is added to drinking water as the final stage of treatment to protect public health. Water undertakers monitor chlorine concentrations closely to keep the levels as low as possible whilst keeping water supplies safe. Concentrations can vary throughout the day and year. They may be higher if you live close to a water treatment works.

Some people are sensitive to the taste and smell of chlorine. The taste of chlorine can be reduced by allowing it to stand in a closed container in a fridge until needed. If this does not work, try boiling the water for about five minutes before storing it. This should remove most of the chlorine. If not drunk within 24 hours, it should be used for purposes.

Home treatment devices like a water filter, are generally not necessary but some customers like to use them. These typically make use of activated carbon to absorb chlorine and other substances which can influence the taste of the water. Please note water treatment devices must be of an appropriate quality and standard. If not properly maintained, they may cause water quality problems.

A chlorine or metallic taste, especially in hot drinks, may not be due to the presence of chlorine. Instead, it is more likely to be associated with non-metallic plumbing materials, such as rubber washers, or hoses if you have appliances (such as vending machines, dishwashers, washing machines and garden hoses) plumbed in close to taps used for drinking water. The plasticiser in these products combines with the residual chlorine in drinking water, and when heated forms antiseptic/TCP tasting compounds when are most noticable in tea and coffee.

In the case of appliances this can be remedied by either changing the hoses for ones which are compliant with BS 6920 or installing a double check valve on the supply to the appliance. Garden hoses should always be disconnected from the hose union tap when not in use and should ideally be fitted with a trigger release gun for when in use.