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Water quality problems.

If you think there is a problem with the water quality, please take a look below to see what the problem could be.

Water quality FAQs.

My water looks strange.

This is likely to be caused by trapped air in the pipework or dissolved chalk particles.

What does this mean?

Air can get into the water supply following a repair on our water pipe network, or by a pocket of air becoming trapped in the pipework inside your home. Water with air in has a cloudy or milky white appearance. This is because of the concentration of thousands of tiny air bubbles that make the water look white.

A fine white sediment is formed when chalk deposits rise from the natural minerals found in water. Drinking water supplied by us is generally described as hard, and has a higher concentration of natural minerals than soft water. The presence of undissolved chalk has a powdery white appearance.

In each case, there is no risk to health although the appearance of the water may be unappealing.

If you have a domestic water softener fitted it can release chalky white pieces of scale over time.
It is advisable that any domestic softeners are fitted downstream of the drinking water tap, and are maintained according to the manufacturer's instructions.

Find out if the cause is air or chalk using our Glass Test:

Fill a glass with water from the cold kitchen tap and watch how it clears. Water with air in can take up to ten minutes to clear, and will clear from the bottom of the glass upwards. Water containing chalk takes an hour or more to clear, with the glass clearing from the top downwards. A fine sediment will then be left on the floor of the glass.

Any white water in the mains network should clear within two to three hours. After this time the tap should be run for two to three minutes to check that the problem has cleared.

However, if the problem persists please contact us for further advice. It should be noted that aeration can also be caused by mixer taps or supataps forcing air into the water stream.

The most common cause of brown, orange or yellow water is iron particles suspended in your water. Small rust fragments may also be present.

There are many possible sources of iron particles found in your water:

  • Iron can occur naturally in some raw waters which are taken for drinking water treatment. Iron salts can be chemically dosed into water during treatment. This encourages the unwanted solids to stick together making it is easier to remove them.
  • The disturbance of iron deposits in some mains can also lead to iron particulate in water. Iron deposits can be caused by the corrosion of cast iron pipes, or by dissolved iron in the water falling out of solution. Changes within the mains network, such as vibrations through the ground or the use of a hydrant, can dislodge the particles and they move around the pipework.
  • Your plumbing at home can also be a source of discolouration, particularly if it has undergone recent work. The discolouration is not harmful, but take care to avoid the use of water until it has cleared. The taste of the water may not be of the usual standard and it may stain clothing.

To potentially identify the cause of the discoloured water you may like to consult with a neighbour. If the discolouration is isolated to your tap it is likely that there is an internal plumbing issue, but if your neighbour is also affected it may be the supplying main. In either case, allow the system to settle for one hour and then run the affected tap for two to three minutes.

To avoid common issues make sure that your internal plumbing system is compliant with Water Supply and Water Fittings Regulations.

For further information about looking after water in your home: 

Water UK guidance on how to look after water in your home

If the problem persists contact us for further advice. If the problem lies with the domestic system then we will be able to advise you on plumbing services in your area.

Manganese is found naturally in some raw waters, and is often combined with iron or chalk. Manganese deposits may move around the water mains network if there is a disturbance to the pipework.

Hardness

Black water can also be caused by the build-up of hardness scale in your pipework which has been stained black by traces of manganese.

If any work is performed on the domestic water system this may dislodge these deposits into the water.

Health

Black discolouration caused by manganese is not harmful, but care should be taken to avoid the use of water until it has cleared.

The taste of the water may not be of the usual standard and it may stain clothing.

How to solve the problem

Under normal conditions, water will return to its usual quality after a short time. Allow the water system to settle for approximately 1 hour, and after this time run the tap for two to three minutes to check the water is running clear.

If the problem persists please contact us for further advice.

Regularly use your water to discourage stagnation and warmth. These contribute to bio-film growth. This is created when manganese particles have grown and are stuck in your pipework.

If this breaks down you may observe black particles in your water.

If necessary, ensure your cold water pipes are suitably insulated if they run close to the hot water pipes or central heating pipes.

Jug filters and tap washers

There are two other common causes of black particles in drinking water - carbon particles from jug filters and disintegrating tap washers. Jug filters can contain activated carbon filters which may leak black particles into the water.

Fill a glass with water from the cold kitchen tap and compare it with water from the jug filter. If the black particles only appear in water from the jug filter then refer to the manufacturer's instructions.

If the black particles are large and can be compressed between the fingers then the fragments are likely to come from a disintegrating tap washer. The washers should be examined and replaced as necessary.

Advice on suitable fixtures and fittings is available from the Water Regulations Advisory Scheme who publish a list of suitable materials for plumbing systems.

Visit the Water Regulations Advisory Scheme website.

Turquoise green or blue water is commonly caused by high concentrations of copper.

Copper is rarely present in raw waters, but may get into in to water supplies from copper pipes used in internal domestic plumbing.

The build-up of hardness scale in new internal pipework and new properties gradually reduces the quantity of copper.

If you have an internal water softener fitted, the amount of copper released may be increased as it can corrode the protective scale coating.

In extremely high concentrations copper can give water a very unpleasant taste, and can cause vomiting.

To avoid common issues make sure that your internal plumbing system is compliant:

Water Supply and Water Fittings Regulations.

For further information about looking after water in your home:

Water UK guidance on how to look after water in your home

My water tastes or smells strange.

Chlorine is a disinfectant which has been used for many years in the water industry to make water safe to drink. Disinfection plays an important role in protecting public health by killing harmful bacteria. Using chlorine is better than using other disinfectants as it is effective from our treatment works right up to your tap.

Your water may occasionally smell or taste of chlorine after we have made a change to our water treatment processes. The level of chlorine dosed into your drinking water is carefully controlled and monitored.

We strive to keep the level of chlorine constant. Unavoidable operational changes at our treatment works, or in our distributing pipes, may result in a slight taste of chlorine. Chlorine leaves our treatment works at less than one milligram per litre (one part per million), the level recommended by the World Health Organisation. By comparison, water found in swimming pools typically contains 3 milligrams per litre of chlorine which is easy to smell.

Treating drinking water with chlorine poses no risk to health. If you’re concerned about the taste then a good way to let the chlorine evaporate is to fill a jug with water and refrigerate it overnight. Water kept like this should be treated as a perishable food and be consumed within 24 hours.

Domestic water filters or jug filters (both of which can contain activated carbon) can be used to remove chlorine from tap water. These filters should be used in accordance with the manufacturer's instructions. There is no reason to use either type of filter on health grounds, as tap water containing chlorine is perfectly safe to drink.

This is often caused by high numbers of harmless micro-organisms, particularly fungi.

Micro-organisms occur naturally in all water types and their numbers increase during the summer. This growth can be a particular problem in domestic systems, especially if the water has been allowed to stagnate.

In addition, when your hot water system warms your cold pipes, favourable conditions are created for microbial growth. Fungal growths or slimes may occur around taps and other water outlets, and in some cases be seen hanging from tap spouts.

While unappealing, these growths do not pose a risk to health.

What can I do to solve the problem?

  • If the property has been unoccupied for some time then run your cold kitchen tap for approximately five minutes and then leave to stand for one hour.
  • Check how close your hot and cold pipes are, and insulate if necessary.
  • Use a chlorine-based disinfectant to remove fungal growth and slime.
  • Ensure that you regularly use your water at home.
  • When not in use, close the in-line control valves on your dishwashers and washing machines if they are plumbed in upstream of the drinking water tap. Check that the machine has a non-return valve fitted.

If the problem persists, consider replacing any new plastic pipework in your home as this can potentially cause an earthy or musty taste.

  • Non-return valves and connection hoses within a plumbing system can wear out over time. Check on the condition of both the valve and the hose, and replace if necessary.
  • Ensure that any outside taps with hosepipes attached have a non-return valve fitted to protect your water.

To avoid common issues make sure that your internal plumbing system is compliant with Water Supply and Water Fittings Regulations.

For further information about looking after water in your home: 

Water UK guidance on how to look after water in your home

This can be caused by chlorine in tap water reacting with particular substances or materials to produce new chlorine compounds.

These new compounds are often formed by the reaction of chlorine with tap washers, plastic kettles, washing machines, dishwashers, connection hoses, rubber anti-splash attachments and plastic pipework.

There is no health risk associated with this type of taste, although the water can be unappealing.

Advice on suitable fixtures and fittings is available from the Water Regulations Advisory Scheme who publish a list of suitable materials which do not react with chlorine.

Below is a list of common issues and possible actions you can take:

Kettles

Chlorine compounds can react with some plastic kettles. You may notice this when the water is boiled, and is particularly evident in new kettles. New kettles should be boiled and the water discarded at least twice before being used for hot drinks.

To confirm whether the kettle is the problem, try making a hot drink with water boiled in a saucepan and compare the taste with a drink made from the kettle. If the taste has gone away then the cause is likely to be your kettle.

Household appliances

When not in use, close the in-line control valves on your dishwashers and washing machines if they are plumbed in upstream of the drinking water tap. Check that the machine has a non-return valve fitted.

If the problem persists, consider replacing any new plastic pipework in your home as this can potentially cause an earthy or musty taste.

Non-return valves and connection hoses within a plumbing system can wear out over time. Check on the condition of both the valve and the hose, and replace if necessary.

Ensure that any outside taps with hosepipes attached have a non-return valve fitted to protect your water supply.

To avoid common issues make sure that your internal plumbing system is compliant with the Water Supply and Water Fittings Regulations.

For further information about looking after water in your home take a look at the Water UK Looking After Water in your Home guidance.

When water has been unused for a long period of time it stands still in the metal pipework in your plumbing system at home. The dissolved metals can form granules which look like sand.

Metallic domestic pipework needs to have been installed in a particular order: galvanised iron, iron, lead and copper. If it is in any other order then metal compounds may be broken down and released from the pipework.

The fitting of a domestic water softener can cause metals from the pipework to enter the water supply, particularly if the water is very soft.

Metallic compounds are normally harmless to health unless levels increase. If you are concerned about a metallic taste and odour contact us immediately for further assistance.

Below are some suggestions which might help solve the problem:

  • If the property has been unoccupied for some time then run your cold kitchen tap. This water can be collected in a bowl and used for purposes other than drinking and cooking.
  • If a water softener is fitted, check it has been installed correctly and is operating as described within the manufacturer's instructions.
  • If you have concerns over the order and type of metallic pipework in your home then it may be necessary to arrange a plumbing inspection of your pipework. We can help you arrange this. We can help you arrange a pipework inspection.
  • When not in use, close the in-line control valves on your dishwashers and washing machines if they are plumbed in upstream of the drinking water tap. Check that the machine has a non-return valve fitted.
  • If the problem persists, consider replacing any new plastic pipework in your home as this can potentially cause an earthy or musty taste.
  • Non-return valves and connection hoses within a plumbing system can wear out over time. Check on the condition of both the valve and the hose, and replace if necessary.
  • Ensure that any outside taps with hosepipes attached have a non-return valve fitted to protect your water supply.

To avoid common issues make sure that your internal plumbing system is compliant with Water Supply and Water Fittings Regulations.

For further information about looking after water in your home:

Water UK guidance on how to look after water in your home

Other issues.

Lead is commonly found in the environment and can  come from sources such as vehicle exhaust fumes and old paint. Lead can also be present in food, water, air and soil, and is able to build up over time in the human body which can have health implications.

There are no significant levels of lead present in the drinking water we supply as it leaves our treatment works. The network of mains, which transports the water to your tap, are not made from lead.

However, lead pipes have been used at some individual properties to connect the domestic system to the mains. Over time, lead can come out of these pipes and enter the drinking water supply for that property.

Additionally, lead can also be found in some copper piping where two metals have been fused together. Lead pipes were used up to the 1970s to connect individual properties to the water mains, and were also used for the internal plumbing. If your home was built before 1970 then it may contain lead pipes, but if your home was built after 1970 then it is unlikely.

The pipe connecting the water main to your cold kitchen tap is called a service pipe and comprises of two parts - the communication pipe and the supply pipe. We are responsible for the communication pipe and the property owner is responsible for the supply pipe. If your service pipe is made of lead we recommend it is replaced.

More information about lead

Seasonal changes can affect the temperature of water in our pipes which unfortunately we can do little about. However, if the temperature from your cold kitchen tap seems unusually warm it may be because your cold water pipe runs very close to a hot water or central heating pipe in your home.

To resolve the issue make sure that your hot pipes are appropriately insulated where necessary.

Alternatively, run your taps briefly and keep a jug or bottle of cold water in your fridge for drinking. It should be noted that water kept like this should be treated as a perishable food and be consumed within 24 hours.

During summer months, the temperature of the water in our mains may be higher as a result of hot weather and higher underground temperatures. There is no health risk associated with this higher temperature.

These types of stains are usually produced by common bacteria or yeasts which can settle and grow on damp surfaces (e.g. tiles, showerheads, toilet bowls and sink drains).

The bacteria, which produces a pink pigment is a common environmental organism and thrives in warm, moist conditions.

The presence of a pink or dark grey film does not indicate a problem with the mains water quality, but suggests a problem with your plumbing at home

Frequently clean any surface that is prone to pink or dark grey staining with a chlorine-based disinfectant to remove and control the problem.

In addition, keeping bathtubs and sinks wiped down and dry following their use will help prevent the problem.

Insects and aquatic invertebrates can live in raw waters that are used for drinking water supplies.

Treating the water before it is put into the mains network removes the organisms.

However, there is a small risk they may enter the water supply if a water main is damaged.

These organisms can also be found in domestic toilet cisterns that are improperly sealed or installed, and can also crawl into tap spouts.

Insects and aquatic invertebrates in drinking water may pose a small risk to health and are understandably unappealing.

If you find any insects or aquatic invertebrates in your mains drinking water, flush the cold kitchen tap for five minutes.