Frequently asked questions about drinking water

What causes discoloured water?

On the Isle of Man there can be occassions when there are incidents of discloured water. The most usual reason for discoloured water on the Isle of Man is due to disturbance of iron and manganese deposits present in the water mains. This can happen when there is a change in the direction or speed of flow of the water. Changes in flow can occur for many reasons

Burst on a water main
Opening or closing of valves
Bringing a mains back into use after repairs
Having to move water from one area to another to cope with changes in demand
Heavy use in one area such as the use of water for fire fighting

These problems can turn the water orange, brown, black or grey. It may also be white as a result of excess air.

The raw water in the Isle of Man is naturally coloured, soft and acidic. The intensity of the colour can vary depending upon the season and level of rainfall. All our water is treated at our treatment works, where all this colour caused by the dissolved organic matter, iron and manganese is removed.

Why are there deposits in the mains?

Over time deposits have built up in the water mains. The principle causes for this are as follows:

On the Isle of Man iron and manganese are present in the source water. Inadequate treatment in the past through the old decommissioned treatment plants has resulted in iron, manganese and other deposits forming in the mains
Many of the water mains on the Isle of Man are cast iron. The older ones are unlined and have corroded. The iron corrosion particles (rust) become loose and can be picked up by the water

The Authority will be dealing with removing the deposits from the mains by cleaning, and tackling iron corrosion by lining or replacing the affected mains. We will be targeting the worst affected areas first.

Are these deposits harmful to health?

If the discolouration is due to mains deposits, these are mostly iron and manganese as such are not likely to be harmful to your health. However you may not wish to drink the water, or give it to your family, because it looks or tastes unpleasant.

White water caused by excess air clears from the bottom up on standing freshly poured water in a glass and is not something to worry about. Sometimes a white scum may form around the side of the glass. This is due to a phenomenon known as surface tension, which traps some of the tiny bubbles at the waters surface. The water is not likely to be harmful to your health. However, if the problem persists please contact us.

What should I do if I get discoloured water?

If you and your neighbours are getting discoloured drinking water then you should contact our Customer Services team on 695949 or the emergency number, 695999. They will advise you as to whether the situation can be improved by running your cold water taps.

If it is only you and not your neighbours getting discoloured water, the problem may be with your pipework in your home. If you notice discoloured water or odour from any of your taps that are not served directly from the public water main, you may have a problem with a storage tank within your property. You should make sure that your storage tank in your house has a close-fitting lid and it is cleaned on regular basis.

If you are in any doubt, we may be able to give you advice or you could contact a qualified plumber, such as one registered with the Institute of Plumbing.

Washing

If your washing has been discoloured because of the water, repeat the wash when the water is not discoloured without adding fabric softener.

If it is still discoloured then please get in touch with us.

Where can I get more information about drinking water quality?

We publish an Annual Report, which is available on request or can be downloaded from our website. We also produce a useful guide, “Water Quality Standards – The Facts”

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