Information Leaflet
Discoloured Water

1. What causes discoloured water?
2. Why are there deposits in the mains?
3. Are these deposits harmful to health?
4. Is anything being done about this?
5. What should I do if I get discoloured water?
6. What will the Inspectorate do if I get discoloured water?
7. What about compensation?
8. Where can I get more information about drinking water quality?

Drinking water in England and Wales is of a very high quality but occasionally things go wrong. Sometimes this can lead to people getting drinking water which is discoloured. This leaflet answers the questions most often asked about discoloured water.

What causes discoloured water?

There are many possible causes, but the most usual reason is the disturbance of any 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 a number of reasons, for example, a burst on a water main, the opening or closing of valves, bringing a mains back in to use after repairs, a water company having to move water from one area to another to cope with changes in demand and use of water for fire fighting.

Very occasionally it may be caused by the condition of your service pipe connecting your house to the water main or the condition of the internal plumbing within your house.

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

Why are there deposits in the mains?

There are two basic reasons.

(a) Many of the water mains in this country are cast iron. The older ones are unlined and they have corroded, especially in areas where the water is soft. The iron corrosion particles (rust) become loose and can be picked up by the water.

(b) In some areas, iron and manganese are present in the source water. Inadequate treatment in the past may have resulted in iron, manganese and other deposits forming in the mains. Chalk can also be deposited in the mains if softening plant is not working effectively.

Are these deposits harmful to health?

If the water is discoloured you should not assume that it is safe to drink until you have sought advice from your water company. 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.

Is anything being done about this?

Water companies should maintain their distribution systems to minimise the amount of deposits in the mains, by carrying out flushing or other means. They should also operate their systems to avoid the deposits being picked up by the water flow.

Water companies are dealing with iron corrosion by lining or replacing the affected mains. They are tackling the worst affected areas first. A few water companies have already completed these programmes but others will take up to the year 2010 to complete them. There are about 315,000 kilometres of water mains in England and Wales, although not all will need work on them.

What should I do if I get discoloured water?

If you and your neighbours are getting discoloured drinking water then contact your water company immediately. Enquiry and emergency numbers are listed under WATER in your telephone directory.

You should also put a sample of the water in a clean glass bottle or jar, seal it and keep it to show to the water company. Please make a note of the date and time you took the sample. If possible, take two samples and keep one in case the Drinking Water Inspectorate becomes involved. Please also make a note about the appearance of the water when you take the sample and any problems that you experienced in using it.

If the water company does not give you a satisfactory explanation or does nothing then you should contact your local WaterVoice office. You will find their number in your telephone directory. WaterVoice may then involve us, the Inspectorate, in investigating your complaint.

Your water company has to notify the Inspectorate of any widespread incident involving discoloured water. We then investigate the cause and assess the appropriateness of the actions taken by the water company. The water company must also notify the local authority and health authority of any problems.

If it is only you and not your neighbours getting discoloured water, the problem may be with your pipework in your home. Your water company may be able to give you advice or you could contact a qualified plumber, such as one registered with the Institute of Plumbing or approved by your water company.

What will the Inspectorate do if I get discoloured water?

When we investigate a discoloured water incident or complaint, we may require the water company to carry out work to prevent the problem from happening again.

We would also start a prosecution of:

• We can show that the drinking water supplied was unfit for human consumption; and
• We do not believe that the water company did all that it might reasonably have been expected to do to prevent the discoloured water.

For those cases that do not justify full Court proceedings we can issue a caution. The Court could take cautions into account in any future offences.

We may ask for your help by agreeing to be interviewed by one of our Inspectors and making a statement about the quality of your drinking water explaining why you did not use it or drink it.

What about compensation?

You should contact your water company if you think that you have suffered loss or damage as a result of being supplied with discoloured drinking water. If you are dissatisfied with the company’s response then you should contact your local Consumer Council for Water office  (formerly WaterVoice).

Where can I get more information about drinking water quality?

Your water company's public record

You can see the record at one of the company's offices. Customer services staff will explain the result of tests and tell you what is being done to rectify any failures. You are entitled to a free copy of the record for the area in which you live. Alternatively, you can write to the company for details.

Your local authority

Water companies are required to give local authorities information about the quality of water supply in their areas.

Our Annual Reports

These are lengthy reports containing a great deal of detailed information about the quality of drinking water in England and Wales. They can be bought from The Stationery Office. You may be able to see a copy at a main library or at your water company's offices.

Our leaflet "How Good is Your Drinking Water"

This is produced each year and is a brief summary of our Annual Report.