We’re committed to delivering high quality water to our customers.

On average, we supply 83 million litres of water to over 138,000 homes and 8,000 business customers.

Our treatment processes ensure that our water is clean and pleasant to drink.

Every drop we supply has to meet the highest standards for taste, appearance and cleanliness.

Find out more about water quality results of all water companies, on the Discover Water website.

Before we are able to supply your water we must meet strict drinking water standards. To do this all of our water goes through a treatment process.

First we pass water through huge sieves, removing large debris such as leaves, twigs and rubbish.

Smaller particles such as dirt and bacteria are then removed by adding carefully controlled quantities of chemical to the water. This causes the particles to stick together, forming a dense layer that sinks to the bottom. This settles as sludge and is removed.

The clear water then flows through layers of gravel and carbon, filtering the water. The carbon also removes traces of organic material such as pesticides.

Finally, to make the water safe to drink, it is disinfected with chlorine. This removes any remaining germs or bacteria and ensures the water remains safe through our network of pipes and out of your tap.

Find out more about how your water gets to your tap.

Chlorine is added during water treatment as a disinfectant to kill harmful bacteria.

This is to ensure the quality of the drinking water is maintained through the pipe network to the point when it reaches your tap.

The very low concentrations of chlorine used to clean water are entirely harmless and continually monitored. Water leaving our treatment works will contain less than one part per million of chlorine and this will reduce further before reaching your home.

Fluoride is a naturally occurring substance present in drinking water in varying concentrations.

Regulations allow for up to 1.5 milligrams of fluoride per litre of water (1.5mg/l) to be present in drinking water.

In some areas across the UK, the level of fluoride is adjusted upwards to a target level of 1mg/l in order to improve dental health.  At Cambridge Water, we do not adjust the fluoride level in this way.

Fluoride is useful for babies and children who have growing teeth and helps reduce tooth decay and cavities.

There is no health risk associated with water hardness, and there are some claims that hard water may even have health benefits.

When water falls as rain, it's "soft" and free of minerals. It picks up naturally occurring minerals, such as calcium and magnesium, as it passes through rock, sand and soil. This causes the water to become ‘hard.’

Calcium also forms an essential part of our diet. Most of our recommended daily amount comes from eating dairy products or bread, but drinking water also has a positive effect.

Find out more about hard water.

Installing a water softener is a matter of personal choice.

We recommend that if you install a water softener you keep a mains water source for drinking purposes. This is because some water softeners increase sodium levels, which may have negative impacts to health.

We can't provide up to date advice on selecting a water softener, but by contacting an approved plumber, you can get professional assistance.

Find an approved plumber.

An earthy taste may sometimes occur in water supplied from a surface water source such as an open reservoir.

It may also be the result of water standing in the pipework for a long period of time.

To improve the taste of your water you should flush your taps for 2-3 minutes. This will remove any water which has been standing in the pipework.

Chlorine is added during water treatment as a disinfectant to kill harmful bacteria. This is to ensure the quality of the drinking water is maintained through the pipe network to the point when it reaches your tap.

The very low concentrations of chlorine used to disinfect water is entirely harmless and regularly monitored. Water leaving our treatment works will contain less than one part per million of chlorine and this will reduce further before reaching your home.

Some people are more sensitive than others to the smell or taste of chlorine and may become aware of occasional changes in chlorine levels in their tap water.

For example, the taste of chlorine may be more noticeable at times of day when water use is high. This is because the water is reaching you quicker and contains more chlorine than when it has been standing in the pipes.

Levels of chlorine may also become more noticeable if we’ve been working on the water mains or if we have to supply you with water from a different water treatment works.
If you find the taste of chlorine unacceptable, a good solution is to fill a jug of tap water and keep it in the fridge. Not only will the chilled water taste better, it will lose that chlorine smell. Keep the jug covered and do not keep any water for more than 24 hours.

If you are still worried about the taste or smell of your drinking water please contact us.

Some people are more sensitive than others to the smell or taste of chlorine and may become aware of occasional changes in chlorine levels in their tap water.

For example, the taste of chlorine may be more noticeable at times of day when water use is high. This is because as the water is reaching you quicker and contains more chlorine than when it has been standing in the pipes.

Levels of chlorine may also become more noticeable if we’ve been working on the water mains or if we have to supply you with water from a different water treatment works.

Reducing the taste of chlorine
If you find the taste of chlorine unacceptable, a good solution is to fill a jug of tap water and keep it in the fridge. Not only will the chilled water taste better, it will lose that chlorine smell. Keep the jug covered and do not keep any water for more than 24 hours.

A metallic taste to your water is most likely due to a reaction between the water and pipework in your plumbing system. This may be particularly noticeable when the water has been standing in the pipework for some hours.

Flushing your taps for 2-3 minutes should help to clear this water, improving the taste.
Boiling water more than once may also make the metallic taste more apparent, so use fresh water each time you boil the kettle.

If your water has a diesel or petrol smell or taste please contact us.

A taste or smell of rubber, plastic, disinfectant or TCP is usually caused by common household plumbing arrangements or appliances.

Appliances
Most dishwashers and washing machines are now connected directly to the mains water supply but are sometimes not installed correctly.

All connections should include a single check valve so that water within the flexible hoses of the dishwasher or washing machine, cannot return to the mains supply and reach the kitchen tap.

If it does not have a check valve you are likely to get a rubber, plastic, disinfectant or TCP taste and odour in your tap water.

Flexible hoses
Flexible hoses can also deteriorate over time and release traces of chemicals that can cause 'chemical' type tastes and odours that are particularly noticeable with hot drinks.
Fitting a single check valve, which are available from DIY stores, will prevent this problem.

Kettles
If you notice unusual 'medicinal' or 'plastic' tastes only in hot drinks this can be due to the seal that separates the kettle's heating element from the water. This is particularly noticeable in new kettles.

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

If you are still worried about the taste or smell of your drinking water please contact us.

We aim to supply all of our customers with high quality water.

Occasionally, the water can look cloudy or milky white in colour. This is probably because air has got into the water supply.

Air in the water is harmless, so it is completely safe to drink.

Air can get into the supply through a number of ways. It may occur if there’s been a burst water main in your area or if we’ve been carrying out maintenance work. It could also be caused by your internal plumbing.

To check if there is air in your supply, fill a glass of water and let it stand for a few minutes. The glass should clear from the bottom upwards. This clears because the air bubbles start rising to the surface.

Advice: To clear the aeration, simply run your kitchen tap, and then adjust your inside stop tap at the same time. Do this by slowly opening and closing the stop tap a couple of times to release any trapped air in the internal plumbing.

If your water has been cloudy for more than a day or so and your neighbours are also affected, or if a glass of water clears from the top downwards, please contact us.

Black, brown, orange or yellow looking water is usually the result of a sudden change in direction of water within iron mains, which can disturb iron and manganese particles that settle in the bottom of the water pipes.

It can occur when work is taking place in the area, for example: if repairs are being carried out on a burst main, the fire service are testing their water hydrants, or water is being moved to supply a different area.

Discoloured water is normally short-lived and doesn't usually last for a long period of time. The only way to clear it is to let it work its way through the system. Running your tap will help to flush the discoloured water through.

Advice:  Run the cold kitchen tap at steady flow for 20 minutes, or until your water runs clear. If it hasn't cleared, wait for a couple of hours and repeat the process. If it hasn't cleared within 4 to 6 hours, please give us a call and we will look into this for you.

Please note: If your water is discoloured, don't use a dishwasher as the particles may cause a blockage. Don't use your washing machine either, as the particles may stain your washing.

In all of these cases, although the water may look unappealing, there is no risk to your health. If the problem carries on, or if you do have any concerns, please contact us.

We are continually reviewing the condition of all of our water mains and pipes and carry out routine flushing to remove any particles which may discolour the water.

Most internal household water pipes are made from copper.

In very new buildings, or buildings with new plumbing, small quantities of copper can dissolve into the water until a natural protective layer builds up on the inside of the pipes.

If water has stood in contact with copper pipes for a long time it can develop a blue tint, which is especially noticeable in white baths and sinks.

Advice: This problem should only last for a few days until a protective layer forms.

Older internal plumbing made of copper can also cause blue discolouration and may need checking or replacing by a plumber.

If it continues then you need to contact the house builder or an approved plumber.

Blue looking water can also be a result of back syphonage from the toilet cistern. The use of blue loo blocks and depressorisation can result in the appearance of blue water from taps in the property.

If you experience this or have other concerns please contact us.

Customers sometimes notice a build-up of slime or staining on fixtures and fittings in areas where water is present.

Common problems include black mould on taps or black, red or pink staining to tile grouts or shower curtains.

While this can raise concerns about the quality of water these problems are not connected with the mains water supply.

How does staining occur?
Bacteria and fungi exist naturally in the air and remain invisible to the human eye. However, they grow quickly and become more visible in warm, moist environments especially when they have a source of nutrients. Typical forms of nutrients include shampoo, soap, spray from
aerosols, washing powder, household dust and food. This visible black slime or staining is called a biofilm.

Where do they form?
Bathrooms and kitchen are ideal places for biofilms to grow. They will form more readily on rough surfaces, such as limescale.

Common places include the inside of cold taps where they can form a slimy or jelly like deposit which hangs from the end of the tap.

They can also be found:
- Around the base of tap fittings
- In showerheads or on shower curtains
- On tile grout
- In drains or plugholes
- In toilet cisterns or bowels
- In washing machines, particularly around the powder draw or door rim.
- In refrigerator drip trays or ice making machines
- In drinks vending machines
- In dehumidifiers

Bacteria and fungi exist naturally in the air and remain invisible to the human eye.

However, they grow quickly and become more visible in warm, moist environments especially when they have a source of nutrients. Typical forms of nutrients include shampoo, soap, spray from aerosols, washing powder, household dust and food. This visible black slime or staining is called a biofilm.

Bathrooms and the kitchen can be perfect environments for biofilms to grow. They will form more readily on rough surfaces, such as limescale.

Common places include the inside of cold taps where they can form a slimy or jelly like deposit which hangs from the end of the tap.

They can also be found:
- Around the base of tap fittings
- In showerheads or on shower curtains
- On tile grout
- In drains or plugholes
- In toilet cisterns or bowels
- In washing machines, particularly around the powder draw or door rim
- In refrigerator drip trays or ice making machines
- In drinks vending machines
- In dehumidifiers

While they don’t look attractive, biofilms do not generally pose a risk to health. Some may cause an allergic reaction in susceptible people.

There are three easy steps to dealing with biofilms:

Improve ventilation
This will allow damp areas in kitchens and bathrooms to dry quickly. Open a window after showering or cooking, install an extractor fan or keep trickle vents open in double glazing. Using a dehumidifier can also help.

Routinely clean all surfaces which can be affected:

Taps: Black slime associated with tap fittings can be easily removed by cleaning inside the tap with a small brush (or old toothbrush) dipped in a mild bleach solution. You should run water to flush the tap before use.

Kitchen surfaces: These can be wiped down with a household cleaner or a mild bleach that will kill the bacteria and fungal spores.

Tile grouts, silicon sealers, shower curtains and rubber materials: In addition to a household cleaner, mould and mildew cleaner is also particularly effective. If growths are not removed on a regular basis they can cause permanent staining.

Limescale: Remove using a standard household cleaning product or a solution of bicarbonate of soda.

Washing machines: Running the washing machine at 60C or above regularly will kill the microbes. Leave the powder drawer and door open after use to allow it to dry out between loads.

Fridges: Clean, and change filter cartridges according to the manufacture’s guidelines.

Water filters and softeners: These can encourage biofilm growth. Make sure they are serviced according to the manufacturer’s instructions.

Ensure fittings can be easily cleaned
For example, when purchasing taps try and avoid ones with plastic inserts as these are commonly associated with biofilms. If your taps do have plastic inserts or detachable fittings they should be regularly removed, cleaned and disinfected.

If your house was built before 1963 it may have lead water pipes. If you are unsure, you can make some simple checks:

Look at the pipework inside your home, such as the pipes leading to the kitchen tap or the pipe which leads to your internal stop-tap (usually under the kitchen sink).

Unpainted lead pipes are dull grey and soft. If you scrape the surface gently with a knife or coin you will see the shiny, silver-coloured metal beneath. Tapping a lead pipe with a metal object will produce a dull thud rather than a clear ringing.

As a guide other pipe materials have the following appearances:

Copper - bright or dull orange in colour, and hard
Iron - dark, very hard and may be rusty
Plastic - may be grey, blue or black

To identify whether you have lead pipes supplying your property open the stop tap chamber outside your property and examine the pipe which leads from the stop tap back to your property to see if it has the lead appearance described above.

If you are still unsure whether your pipes are lead, or if you are unable to reach your pipes, a plumber will carry out these checks for you.

Find an approved plumber

If you suspect that you have lead pipes, then please contact us and we will be happy to check the lead content of your tap water.

The water leaving our treatment works and travelling along our network of pipes is virtually lead-free.

You should only need to check the lead levels in your water supply if lead has been used in the pipework supplying your property or for internal plumbing.

If you suspect that you have lead pipes, then please contact us and we will be happy to check the lead content of your tap water.

If you have checked your property has lead pipes and you suspect that you have lead pipes, then please contact us and we will be happy to check the lead content of your tap water.

In the meantime there are some simple short-term precautions you can take to reduce the effects of lead in your drinking water supply:

Do not drink water that has been standing in the pipes for long periods, for example, overnight, or if the supply has not been used for several hours.

In these circumstances draw off a washing up bowl of water from the kitchen tap to clear the water that has been standing in the pipes. This need not be wasted but can be used on the garden or for something other than drinking or cooking. You can now use water from the kitchen tap as usual.

Ensure you only use cold water for cooking or drinking purposes, as hot water dissolves more lead than cold water.

We’re responsible for the underground pipes that carry water up to the boundary of your property - normally where it meets the footpath.

From the boundary it is the homeowners’ responsibility.

If you have lead pipes on your property and you choose to renew them, we will replace the pipes we are responsible for free of charge if the levels of lead in the water >5ug/l (exceeds 5 micrograms per litre). 

If you share a supply pipe with other properties and you and your neighbours agree to have it replaced you either:

- Ask us to replace the shared section of our pipe free of charge.
- Apply for a separate water supply, at your own cost.

Your local authority may provide a grant for the cost of replacing the lead pipes.

If you would like us to replace our section of the lead supply pipes we will need to investigate the pipework in advance.

If you have questions, please contact us.