Water quality FAQs

Advice on water quality problems, including cloudy or discoloured water, unpleasant taste or odour, Legionnaires' disease, and concerns about lead in your water supply.

Appearance

White or cloudy water is often caused by excess air in the water supply to your home, and is common after an interruption to your water supply - such as a burst water pipe.

Brown water can be caused by naturally-occurring deposits of iron and manganese found in cast iron water pipes.

In both cases, the water usually returns to being clear after slowly running your cold kitchen tap, but if you have any concerns, contact your local water company.

Why is my water discoloured?

On rare occasions tap water may become discoloured, appear cloudy, or appear to have very small particles in it.

Discolouration can range from a light straw yellow colour to dark brown. It can be caused by a number of things including:

  • Naturally occurring substances

  • Disturbance of mains deposits

  • Corrosion of service pipes

  • Internal plumbing issues.

In most cases discoloured water is not harmful and can be cleared by running the first incoming cold water tap (usually in the kitchen) at a trickle until it clears.

Very occasionally water suppliers receive calls about "tiny particles" or "bits" in their tap water. This can be caused by:

  • Planned or unplanned work to the water supply network which causes sediment in the pipes to shift (quite often this is a dark red, brown colour)

  • Small dark grey or black particles can occasionally be caused if your pipework is made from lead. This is most likely if your house was built before 1970.

For more information, please contact your water supplier.

Please note: If your water is blue, pink, green or any other colour not described above, please do not drink the water or use it for cooking purposes until you have sought advice from your water supplier.

Why is my water blue/green?

Blue or green looking water is often due to the presence of new copper pipework, either in new houses or where new pipework has been installed in older properties. This is because these new copper pipes are settling in.

To help prevent this from happening, take the following steps:

  • Only use lead-free flux 

  • Flush through new pipework thorougly

  • Drain down plumbing systems which are not used immediately after installation.

Blue water can also be caused by poorly installed toilet cisterns, which allow water from the cisterns to siphon back into the internal plumbing.

For information about how to check your toilet cistern please visit the WRAS website.

If your water is blue please do not drink the water or use it for cooking until you have sought advice from your water supplier.

Why is my water cloudy or milky?

Sometimes water can look milky or cloudy because it contains tiny bubbles of air. Air is always in water, but it can be more obvious after it has travelled through the mains, if there is a burst mains pipe or if a faulty plumbing fitting has been used.

As well as the change in how it looks, you may also notice knocking or banging noises coming from the internal plumbing.

To check if this is the problem, run a glass of water and allow it to stand for a few moments - the cloudiness should clear from bottom to top. To help fix this, you can try running the cold water tap at the first point of entry in to the property (closest to the internal stop tap) on a slow steady flow. While the tap is running, turn the internal stop tap on/off 4-6 times to help release the air from the pipes.

Cloudy water caused by tiny air bubbles in the water is not harmful to health.

If you've tried this but are still concerned, or you'd like more advice you should contact your water supplier.

How can I improve the appearance of my water?

In this video from Wessex Water, you can learn more about issues with the appearance of your water, as well as tips for how to improve it.


Taste and odour

Watch this short video to know how to tackle strange tastes and smells in your drinking water.


Why is my water discoloured?

On rare occasions tap water may become discoloured, appear cloudy, or appear to have very small particles in it.

Discolouration can range from a light straw yellow colour to dark brown. It can be caused by a number of things including:

  • Naturally occurring substances

  • Disturbance of mains deposits

  • Corrosion of service pipes

  • Internal plumbing issues.

In most cases discoloured water is not harmful and can be cleared by running the first incoming cold water tap (usually in the kitchen) at a trickle until it clears.

Very occasionally water suppliers receive calls about "tiny particles" or "bits" in their tap water. This can be caused by:

  • Planned or unplanned work to the water supply network which causes sediment in the pipes to shift (quite often this is a dark red, brown colour)

  • Small dark grey or black particles can occasionally be caused if your pipework is made from lead. This is most likely if your house was built before 1970.

For more information, please contact your water supplier.

Please note: If your water is blue, pink, green or any other colour not described above, please do not drink the water or use it for cooking purposes until you have sought advice from your water supplier.

Why is my water blue/green?

Blue or green looking water is often due to the presence of new copper pipework, either in new houses or where new pipework has been installed in older properties. This is because these new copper pipes are settling in.

To help prevent this from happening, take the following steps:

  • Only use lead-free flux 

  • Flush through new pipework thorougly

  • Drain down plumbing systems which are not used immediately after installation.

Blue water can also be caused by poorly installed toilet cisterns, which allow water from the cisterns to siphon back into the internal plumbing.

For information about how to check your toilet cistern please visit the WRAS website.

If your water is blue please do not drink the water or use it for cooking until you have sought advice from your water supplier.

Why is my water cloudy or milky?

Sometimes water can look milky or cloudy because it contains tiny bubbles of air. Air is always in water, but it can be more obvious after it has travelled through the mains, if there is a burst mains pipe or if a faulty plumbing fitting has been used.

As well as the change in how it looks, you may also notice knocking or banging noises coming from the internal plumbing.

To check if this is the problem, run a glass of water and allow it to stand for a few moments - the cloudiness should clear from bottom to top. To help fix this, you can try running the cold water tap at the first point of entry in to the property (closest to the internal stop tap) on a slow steady flow. While the tap is running, turn the internal stop tap on/off 4-6 times to help release the air from the pipes.

Cloudy water caused by tiny air bubbles in the water is not harmful to health.

If you've tried this but are still concerned, or you'd like more advice you should contact your water supplier.

How can I improve the appearance of my water?

In this video from Wessex Water, you can learn more about issues with the appearance of your water, as well as tips for how to improve it.


Lead in water

Lead water pipes may be found in properties built before the 1970s when the practice was banned. It can be harmful to health, so this video shows how to check for lead water pipes.


Why is my water discoloured?

On rare occasions tap water may become discoloured, appear cloudy, or appear to have very small particles in it.

Discolouration can range from a light straw yellow colour to dark brown. It can be caused by a number of things including:

  • Naturally occurring substances

  • Disturbance of mains deposits

  • Corrosion of service pipes

  • Internal plumbing issues.

In most cases discoloured water is not harmful and can be cleared by running the first incoming cold water tap (usually in the kitchen) at a trickle until it clears.

Very occasionally water suppliers receive calls about "tiny particles" or "bits" in their tap water. This can be caused by:

  • Planned or unplanned work to the water supply network which causes sediment in the pipes to shift (quite often this is a dark red, brown colour)

  • Small dark grey or black particles can occasionally be caused if your pipework is made from lead. This is most likely if your house was built before 1970.

For more information, please contact your water supplier.

Please note: If your water is blue, pink, green or any other colour not described above, please do not drink the water or use it for cooking purposes until you have sought advice from your water supplier.

Why is my water blue/green?

Blue or green looking water is often due to the presence of new copper pipework, either in new houses or where new pipework has been installed in older properties. This is because these new copper pipes are settling in.

To help prevent this from happening, take the following steps:

  • Only use lead-free flux 

  • Flush through new pipework thorougly

  • Drain down plumbing systems which are not used immediately after installation.

Blue water can also be caused by poorly installed toilet cisterns, which allow water from the cisterns to siphon back into the internal plumbing.

For information about how to check your toilet cistern please visit the WRAS website.

If your water is blue please do not drink the water or use it for cooking until you have sought advice from your water supplier.

Why is my water cloudy or milky?

Sometimes water can look milky or cloudy because it contains tiny bubbles of air. Air is always in water, but it can be more obvious after it has travelled through the mains, if there is a burst mains pipe or if a faulty plumbing fitting has been used.

As well as the change in how it looks, you may also notice knocking or banging noises coming from the internal plumbing.

To check if this is the problem, run a glass of water and allow it to stand for a few moments - the cloudiness should clear from bottom to top. To help fix this, you can try running the cold water tap at the first point of entry in to the property (closest to the internal stop tap) on a slow steady flow. While the tap is running, turn the internal stop tap on/off 4-6 times to help release the air from the pipes.

Cloudy water caused by tiny air bubbles in the water is not harmful to health.

If you've tried this but are still concerned, or you'd like more advice you should contact your water supplier.

How can I improve the appearance of my water?

In this video from Wessex Water, you can learn more about issues with the appearance of your water, as well as tips for how to improve it.


Legionnaires' Disease

WaterSafe member company, the CIPHE, has a wealth of advice on preventing the growth of legionella bacteria and potentially contracting Legionaires’ Disease.

What is Legionnaires' disease?

Legionnaires' disease is contracted by breathing in large numbers of the legionella Pneumophila bacteria. These bacteria are widespread in the environment and are able to thrive in warm water conditions. They can be found in water systems, such as hot water tanks, cooling towers and large air conditioning systems. They are more likely to be found in complex plumbing systems.

Water suppliers treat drinking water with chlorine to kill off bacteria. However, they can continue to thrive in plumbing systems which are not installed or maintained correctly, which is why WaterSafe urges homeowners and businesses to only choose qualified and knowledgeable plumbing businesses.

How can I prevent Legionnaires' disease in my home or business?

Top tips to avoid problems with Legionnaires' disease include:

  • Only use a qualified plumber

  • Ensure suitable fittings are used (Reg 4 compliant)

  • Keep the design of plumbing systems simple

  • Design a system so water is regularly turned over and does not stagnate

  • Ensure hot and cold water are kept at the correct temperatures

  • Businesses should follow the advice within the HSE approved code of practice L8 to ensure they meet their legal duties under the Health and Safety at Work Act 1974 to manage risks from legionella bacteria.

Covid-19 Update:

In May 2020, Water UK published guidance to building owners, landlords and managers on recovering buildings and networks after prolonged inactivity during Covid-19 to avoid risks of adverse water quality and potential risks to health – including legionella bacteria.

Hosepipe safety

To prevent strange tastes or smells, or contaminated water from your hosepipe entering your internal plumbing, we always recommend you disconnect your hose when not in use.

It should also have a suitable backflow prevention device fitted to make sure water doesn’t flow back into your home.

How can I prevent illness caused by backflow from hosepipes?

Many homeowners don’t realise how ill you can get if the water in your hosepipe “backflows” into your drinking water supply, or becomes contaminated by potentially lethal bacteria, such as Legionella, that can thrive in warm, stagnant water and lead to Legionnaires’ disease.

The following simple steps will help protect you and your hosepipe but if in any doubt, always seek advice from a WaterSafe-approved plumber who will be able to ensure you have the right safety measures in place.

  • DO fit an approved double check valve to hosepipes to prevent any water, or contaminants from the garden, ponds or paddling pools, flowing back into your mains drinking water supply
  • DON’T place hosepipes in drains, garden ponds, buckets or watering cans where they can be submerged as contaminated water could be siphoned back into your home’s drinking water pipework
  • DO keep your hose somewhere cool and out of the sun
  • DO turn off your hosepipe at the tap and ideally fully disconnect it when not in use
  • DO fit a self-closing flow control, such as a trigger spray gun, to prevent it being used when unattended.
  • DO gently run the water out of the hose before you use it - without any form of spray attachment on the end
  • DON’T use a hosepipe that has been sitting around and full of warm water to fill a hot tub. The warm water within the tub will allow any bacteria – including Legionella – to quickly grow

Shirley Cramer CBE, Chief Executive of the Royal Society for Public Health

said: “Getting the message out about hosepipe safety is of great importance for the public’s health.

“The RSPH welcomes WaterSafe’s release of their top hosepipe DO’S and DON’T’S - sensible and practical advice that will help prevent those who follow it from potentially contracting serious diseases such as Legionnaires’.”

For more information on the RSPH visit www.rsph.org.uk.





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