Tastes and Smells

 

Why does my water taste or smell strange?

Some people are very sensitive to smell and taste. Drinking water in Scotland is of a very high quality but you may sometimes notice a slight taste or smell, particularly of chlorine. If you do there is no cause to worry.

BUT, if you notice a particularly bad or strong smell or taste which means you cannot drink the water, or you notice a smell or taste for the first time, you should contact Scottish Water immediately. Contact details are listed on this website under Useful Links.

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What causes tastes and odours in water?

Any one of the following could cause people to notice a slight smell or taste in their drinking water:

  • The use of chlorine as a disinfectant
  • Seasonal changes
  • A change in your water supply
  • Moving from one area to another
  • Your plumbing

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What is chlorine?

Chlorine is added to the water to disinfect it and keep it safe to drink. It has to be used carefully, but it is harmless when used in the very small amounts found in drinking water.

It is also commonly used in various brands of sterilisers for baby feeding bottles and is used in higher concentrations to disinfect water in swimming pools.

The amount of chlorine added to water is tightly controlled by Scottish Water, but it is not unusual for a slight taste or smell of chlorine to be noticeable in drinking water.

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Why is it necessary to use chlorine?

It is absolutely essential that drinking water should be safe to drink and contain no harmful bacteria capable of causing diseases. Chlorine has been proven to be the simplest and most effective means of disinfecting water, and has been used in the UK for 100 years. The addition of chlorine in small amounts at water treatment works disinfects the supply and leaves a lasting residual that keeps the water safe until it reaches your tap. The amount of chlorine in water leaving treatment works is safe and well within the World Health Organisation guidelines.

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I don’t like the taste or smell of chlorine in my water – what can I do?

It’s not unusual for a slight taste or smell of chlorine to be noticeable in drinking water, but this shouldn’t make the water unacceptable to most people. DWQR expects Scottish Water to use no more chlorine than is absolutely necessary and to regularly review the amount used.

A simple, safe way to overcome this smell or taste is to place a covered jug of water in the fridge before drinking – this allows the chlorine to disperse and cool water always tastes better.

 

You should throw away any unused water after 24 hours.

A number of domestic water filters are available that will remove chlorine. If consumers choose to use these it is important that they are maintained in accordance with manufacturers’ instructions in order to ensure they remain safe to use. British Water www.britishwater.co.uk is the trade organisation representing suppliers associated with the water industry, and they provide advice on the use of filtration equipment.

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What are disinfection by-products?

Chlorine added to disinfect the water can react with naturally occurring substances in the water to form other compounds, known as disinfection by-products. The main group of disinfection by-products are the Trihalomethanes (THMs), and these have a standard in the Regulations. The standard is set with a wide margin of safety, in accordance with World Health Organisation guidelines.

It is possible to minimise disinfection by-product formation by tightly controlling the amount of chlorine added to the water and by removing as many of the naturally occurring organic substances as possible through the treatment process. Some treatment works in Scotland currently have difficulty in producing water that complies with the standard, and DWQR is working to ensure that these facilities are upgraded as quickly as possible.

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What is Chloramination?

Chloramination is an alternative means that is used to disinfect the water in some parts of Scotland and elsewhere, whereby ammonia is added to chlorine to form a long-lasting disinfectant. It has been in common use within the water industry for many years.

The advantage of chloramination is that it persists longer through the distribution pipework and the taste is usually less noticeable to consumers than chlorine alone.

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What about seasonal changes?

Much of our drinking water is obtained by treating waters taken from rivers and reservoirs. In summer, these waters sometimes have a musty or earthy smell or taste before they are treated. Treatment removes most of these smells and tastes, but less so in hot and dry weather.

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Are these smells or tastes harmful?

No. The slight smell or taste is harmless, however if you notice a strong musty or earthy taste or smell you should contact Scottish Water.

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What if my water supply changes or if I move house?

The content of water is complex and varies from area to area, often because of the different rocks and soils through which it passes.

Treated waters from different areas have different tastes. Hard water from a chalky area will have a very different taste from soft water from a reservoir in the hills. In some parts of the country, Scottish Water can supply treated water from different sources.

If Scottish Water needs to change supplies, for example because of increased use of water in the summer, you may notice a change in the taste. Similarly, if you move to another area you may notice that the water tastes different, although it still complies fully with the standards. Most people become used to the taste of the new supply very quickly.

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Why does my water taste of chemicals or medicine?

Sometimes the small amount of chlorine added to water reacts with chemicals called phenols that are found in certain plastics. These produce a strong taste that may be described as medicinal or even metallic. Usually the cause is an item in the property’s plumbing that is not British Standard approved. Pinpointing the exact cause may require some detective work, or even the services of an approved plumber, but common causes are:

  • Tap washers: Changing the washer for a BS approved one will cure the problem
  • Washing machine or dishwasher hoses connected to the supply: Fitting a non-return valve will prevent affected water being sucked back into the supply
  • Non-approved outside tap ‘kits’ connected to the supply: Fitting a non-return valve will prevent affected water being sucked back into the supply

If the problem is only present in hot drinks, the problem may be due to a kettle. This can be confirmed by using water boiled in a metal pan on the stove to see if that still has the taste. Purchasing a different kettle without plastic in contact with the water should resolve this.

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Why does my water taste of petrol / oil / solvents?

This is not a common problem and should be investigated immediately. First check that the taste / smell is in the water and not derived from the surrounding air in which you are tasting the water, then contact Scottish Water without delay.

Possible causes include spillages of petrol or hydrocarbons that have made their way through the soil and penetrated the plastic main. The usual cause is a petrol or diesel spill on a driveway, but sometimes more than one property is affected.

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