There are a number of reasons why your water supply might have a different taste or smell. Water contains a number of naturally occurring minerals depending on the type of source it is. The different concentration of these minerals can give rise to slightly different tastes.

Occasionally for operational reasons we may need to provide you with a water supply from an alternative source. At these times you may notice a slight change to the taste of your water.

Different types of taste and odour can however develop, which are not associated with natural minerals or changes to the source. In the majority of cases these are associated with the arrangement of the internal plumbing system within the property. Some common tastes and odours are:

Chlorine.
One of the most common questions customers’ ask is why do we use chlorine. Chlorine is an essential part of water treatment and is added during the final stage of treatment to disinfect the drinking water and ensuring it does not contain harmful bacteria, which could potentially cause illness. A small amount of chlorine remains in the water after it leaves the treatment works. This small chlorine residual ensures the wholesomeness of the drinking water is maintained as it moves through our mains’ network to your tap.

The level of chlorine in the water as it leaves the treatment works is typically between 0.5 and 1.0 parts per million (mg/l). However, the amount in the water when it reaches your home will be slightly less, depending on how far you house is from the treatment works and the temperature of the water. The level of chlorine is monitored very closely and our aim is to ensure a small amount remains in the water until it reaches the end of the distribution system. Chlorine levels may vary throughout the day and through the seasons. Occasionally the level may increase for operational reasons, for instance if we have to supply your area from a different treatment works.

The small amount of chlorine present in the water is not harmful but can give the water a slight chlorinous taste. Some people are more sensitive to the taste and smell of chlorine than others and find the water unpleasant to drink. The chlorinous taste can be reduced by leaving a covered jug of water standing in the fridge. It is advisable not to keep the water standing for more than 24 hours. Alternatively boiling the water will also remove the chlorine. These simple methods can provide you with a safe supply of water tasting as good as bottled water and costing you thousands of times less.

Earthy or Musty Tastes and Smells.
There are several reasons for these types of taste with the most common being back flow from a ‘dead leg’ of pipe within the property. Water supplies can contain low numbers of harmless microorganisms, which occur naturally in all waters. Their numbers can increase if water is allowed to stand or stagnate in domestic systems. In addition, the warming of cold domestic pipes by the hot water system can produce conditions favourable for the growth of these microorganisms. If the property has been unoccupied for a period of time, flushing the coldwater taps to remove any standing water could improve the taste. If the taste or odour persists please contact us for further assistance.

Occasionally an earthy taste can develop in the source water due to the breakdown of vegetation. Normally our treatments works will remove the majority of the natural chemicals that cause this taste.

T.C.P. Taste and Odour.
This type of taste or odour has been described as “bitter”, “medicinal” or “astringent” and is commonly associated with chlorine in the water reacting with particular substances or materials in the domestic plumbing system. These tastes may vary depending on how long the item has been in contact with the water. Materials that can give rise to this type of taste include tap washers, flexible hoses used to connect washing machines and/or dishwashers and plastic kettles. In recent years there has been s a growing trend for flexible hoses to be used to connect kitchen and bathroom taps to the plumbing system. There is no health risk associated with the typical concentrations giving rise to this type of taste, although the water can be unpalatable. Unlike chlorine this type of taste is still present in the water after it has been boiled. The following steps are a simple way to determine where the taste is forming:

Step 1. Try boiling some water in a clean metal saucepan and compare this to water boiled in the kettle. This could indicate if the taste is developing in the kettle in which case it is probably associated with the seal between the element and the side of the kettle.

Step 2. Try isolating appliances such as washing machines and dishwashers for several days. After isolating the appliance run the cold tap for a short period to remove any water in the pipe work. If this solves the problem it is recommended a non-return valve be fitted to the coldwater supply to the appliance. Further information regarding this type of taste and how to resolve it can be found on the following information sheet. If a non-return valve is already fitted this could indicate it has failed and needs replacing.

Step 3. Check any recent plumbing work to see if new pipe work could be causing the problem. This could include the use of flexible hoses in other parts of the domestic plumbing system. Alternatively, compare water from the kitchen cold tap with that taken from the bathroom cold tap.

If you are unable to resolve this problem please contact us for further assistance.

Metallic tastes and odours.
These types of tastes or odours are normally associated with increased concentrations of metals such as copper or zinc. If water is left standing in metal pipe work (for example a galvanised supply pipe) for long periods it can pick up metals, which may impart an unusual taste or odour. Running the coldwater tap for a short period can solve this problem. If this taste persists please contact us for further assistance.

Petrol or diesel tastes and odours.
If you notice a petrol or diesel type taste or smell to your water it could be caused by a fuel spill close to your supply pipe or the water main. These types of compounds (including heating oil) can penetrate plastic pipes. If you detect this type of taste or odour in your water supply please contact us for further assistance.