My Supply

Water quality information

Find out info about your wonderful water below, or you can get a report about water quality in your area.

Why isn’t my water clear?

We aim to make sure your drinking water is clean, clear and wonderful to drink every single day. However, sometimes it can be a funny colour or look cloudy.

When the water looks discoloured or dirty, it's usually caused by a burst pipe or leak, which causes the water to flow through the pipes quicker than normal. When this happens, the natural deposits that usually sit at the bottom of the pipe can be disturbed. This makes your water appear dirty. These deposits are usually nothing to worry about, but we understand you might not want to drink the water while it’s discoloured.

If the water is cloudy, or looks milky; this is usually due to air bubbles that have made their way into the supply. Air can get into your water if there is a burst or emergency repair work happening nearby.

Head to check my area to search using your postcode and see if there’s any bursts, leaks or other repairs going on that can cause your water to look different.  


Discoloured Water

If there's a leak, burst or repair work going on nearby to you, you may notice that your water looks dirty or discoloured. We show any ongoing repairs that are happening in your area on the front page, you can also report this to us if you're not sure.

When there's a leak or burst, the water will flow through the mains water pipe much faster than normal. This disturbs the natural sediments which makes your water look dirty. It can be anything from a similar colour to white wine, to a dark chocolate depending on how far away the burst is.  

The best way to clear discoloured water is to run the cold tap nearest to your internal stop tap (usually next to your kitchen tap) at a steady flow for 20 minutes. Run this at a pencil thin flow. Don’t get tempted to give the tap a good blast as that can cause the sediment to be disturbed more, making the problem worse. You may need to do this a few times if the water is very discoloured.

If you've got a water meter, you're entitled to a rebate for running the water through. To request this, contact us and we'll add it to your billing account.

If you’ve tried this a few times, and it’s still discoloured contact us and we’ll look into it for you. 


Milky or Cloudy Water

If your water looks milky or cloudy this can be caused by changes on our network such as bursts or emergency repair work. When there's a burst, millions of tiny air bubbles enter your water supply, which makes it look milky or cloudy in appearance. To check to see if it's air in your supply, fill a glass of water and leave it to one side. If it clears from the bottom up then your water is cloudy due to air bubbles and is just a little more aerated than usual.

The issue will normally resolve itself, but you can help to clear air from your supply pipe. Just run the cold tap closest to your internal stop tap at full flow, then slowly turn the stop tap on and off around 4-6 times. This will help to clear the air in your water. If it's particularly bad, you may have to do this a few times. If it doesn't improve or has been going on for a little while just get in touch and we can help.

If you've got a water meter, you're entitled to a rebate for running the water through. To request this, contact us and we'll add it to your billing account.


Blue or Green Water

Blue or Green water is often found in new homes, or where you've had new pipework put in. The new copper pipes wil be settling in. To help prevent this from happening lead-free flux needs to be used, and new pipe work needs to be flushed thoroughly and
any plumbing systems need to be drained if they won't be in use right away.

If you've not had your pipes replaced, then this could also be due to old copper pipes breaking down. For this, it's worth contacting a plumber for more advice. If you've got a blue loo block, and have noticed a loss of pressure or supply, the blue water could be caused by the water from your toilet flowing back through your home. In this case, simply flush water through your system until it's lovely and clear again.


Bits in the Water

Sometimes you may see bits or particles in your water. Each of these can be due to different things, so check below for more information.

White Bits

Chalk has a white, powdery appearance and is made up of natural minerals found in your water. This is what forms the water hardness levels. Across the UK, there is different levels of hardness depending on where your water comes from. This can sometimes appear in your water as a fine, white sand, small bits in the water or scale found in your kettle.

To test to see if your water has chalk or air bubbles, simply fill a glass with cold water from your kitchen tap. Air bubbles will clear from the bottom of the glass to the top in a matter of minutes. However, chalk deposits can take up to an hour to clear, and will settle from the top of the glass to the bottom. When water with chalk in it has settled, there will be a fine, white sand left at the bottom of the glass.

You can find more information about water hardness a little further down the page.

Blue or Green Bits

Blue or Green bits in your water, if paired with blue or green water can mean that the limescale from your water has become stained from your homes copper pipework. If you've had your pipes replaced, or moved into a new home, this should settle over time. You might wish to run the taps to draw the discoloured water through. 

If you haven't got new pipes, then soft blue bits in your water will usually be chalk deposits that have become stained over time. They may be quite solid if they've been there for a while.

Harder and brighter blue bits may be parts of the mains. If this is the case, or it's been happening for a while, please get in touch so we can help investigate the cause for you.

Black Bits

Black bits in the water, especially if we're working in the area, will usually be the harmless sediment that's been disturbed when a leak or repair has happened. This will settle over time, although we understand you may not wish to drink it.

Sometimes, your pipework and other plumbing such as tap washers may break down over time. This would cause larger and more rubbery black bits in your water. If this is the case, then just contact a plumber to help sort this out for you.

Carbon particles in water filters can also cause bits to come into your water. If you've got a water filter, just change it and you'll be back to having a brew in no time.


What to look out for

Occasionally, the natural characteristics of the water itself may give the water a slight yellow or brownish tint. However, our treatment processes are designed to remove such colour. This can be the case when water comes from upland areas or groundwater sources rich in iron and other minerals. If you feel that your water is particularly discoloured over a long period of time, get in touch and we can investigate this for you.

Your water is high quality and we treat it to make sure it's wonderful and safe to drink straight to your tap.

All water sources contain naturally occurring minerals such as calcium, iron and magnesium in different amounts. This has an effect on the taste of your water. With no minerals, your water would taste flat and unappetising. Everyone's sensitivity to these mineral tastes vary, but you may notice a difference in taste more if you've moved from another part of the country or have been travelling.

There are several common causes of tastes and odours in drinking water, these are highlighted below. If you're concerned about your water please contact us.

Medicinal Taste

A medicinal taste in your water is often caused by a reaction between chlorine and man-made plastic or rubber fixtures such as tap washers and dishwasher hoses. If you've recently got a new appliance, this is the most likely reason for the sudden change in flavour. If this is the case, you can get a check valve which will stop this from happening. Over time the medicinal taste should fade.

If it does continue, contact a plumber to check your plastic and rubber fittings as they may have started to deteriorate. You can find WaterSafe plumbers near you by searching here.

If you're not sure on whether it's a medicinal taste or chlorine taste, boil some water in a saucepan and put a separate jug of water in your fridge. If the cold water improves, then it's the chlorine you can smell, and you can find more info down the page. If the boiled water tastes or smells worse, then this is a medicinal taste.

Earthy Taste

Surface water that passes through peaty land can sometimes develop a musty, earthy taste or smell. This is particularly the case after periods of warm, dry weather. All of our treatment works have processes in place to minimise any unpleasant natural smells. Sometimes, if you've got a long supply pipe, or live in a rural area, you may notice an earthy or musty taste or smell as the water will be left standing in the pipes.  

This is usually noticed more first thing in the morning, or if you've been away on holiday.  If this is the case, flushing the water through by turning a tap on for a couple of minutes should help your water become delicious and refreshing again.

Metallic Taste

If your water has been in contact with copper, iron or galvanised pipes it can sometimes develop a slightly bitter or metallic taste. You may notice this after going away on holiday, or if you have a long supply pipe. Just run the tap closest to your internal stop tap for a minute or two when you get home, so the water that has been sitting there is gone. This will usually fix the problem.

If you have a new home, the metallic taste should stop over time. New copper pipes will settle over time as a layer of natural sediment coats inside the new pipes.  Boiling water more than once can make the metallic and bitter taste stronger. Only boil the amount you need using a fresh kettle full each time so your morning cuppa isn't spoilt. Not only will you notice that your tea tastes better, you'll also save money on your energy bills too.

Sewage Smell

If you notice a sewage taste or smell in your water, it's usually due to a blockage in the sink near to your tap. Our clean water mains aren't attached to the dirty water pipes, so it's unlikely that there's been any contamination.

To see if this is due to a blockage, fill a glass of water and go into another room. Give it a sniff, and see if the smell is still there. If not, this confirms that it's not the water, and using a sink unblocker should help. You can get that from the supermarket.

If you can still smell sewage, then get in touch with us so we can look into it for you.

Petrol Smell

If you've noticed a spillage of petrol, diesel  or other chemicals on your driveway, garden or in the street, it can contaminate your water supply. This can also happen due to land where there has been a petrol station in the past. These substances are easily able to go through plastic service pipes, causing a petrol or diesel smell.

If you think your water has a petrol or solvent taste it's important that you contact us  immediately and we will arrange for an investigation of your supply.

Chlorine Smell

Chlorine levels are present in our water to keep it wonderful and safe for you to drink. Levels can still vary depending on the distance of your home from the water treatment works, the time of year and even the time of day.

You can help ease the chlorine taste by filling a jug with water and popping it into the fridge. Not only will it be lovely and cool but the chlorine will dissappate making your water more delicous to drink.

Always remember, water should be treated as a food stuff and discarded if not used within 24 hours.


Time for a few hard facts

Water hardness measures the amount of natural calcium and magnesium that’s present in the water. As rain falls, there is no calcium or magnesium in your water. As the water flows overland and through rocks, it dissolves natural minerals in the environment.

Your water hardness levels vary depending on where you live. It's generally harder in areas with natural limestone than areas with insoluble rock such as Granite. In case you were wondering, it’s expressed as the equivalent amount of calcium carbonate in parts per million (mg/g) for every litre of water. This is also measured in degrees.

That’s the science lesson over. The important thing to know is that even when the water is very hard it’s not harmful to your health, however it may contribute to worsening of some existing skin conditions such as eczema. If you find this is the case, then contact as Health Professional for advice.

The effects of hard water

Hard water can cause scale to form in kettles, irons and around taps and showerheads. It can also affect your washing machine and dishwasher. You may also find it leaves a layer of dirt or froth around your basins and bath.  Luckily you’ll find lots of scale removing products at your nearest supermarket. It won't affect the performance of laundry detergent or washing up liquid, you may just need to use more to get some suds if you're doing the pots.  


Why is fluoride added to water?

The controlled addition of fluoride to water is added at the request of local health authorities. The process doesn’t affect the look, taste or smell of the water in any way. In fact, fluoride is naturally present in most water supplies, particularly in the case of groundwater. Our job is to increase these levels to the agreed amount, which is 1 part per million (1mg/l). While the exact figure changes from time to time, currently 45% of the water we supply is fluoridated.

Who’s responsible?

In April 2013, the Secretary of State for Health became responsible for existing fluoridation schemes. At the same time, local authorities became responsible for proposing and undertaking consultation on new schemes or changes to existing schemes. The cost of fluoridation is covered by the health authorities and isn’t included in our water charges.



We and all clean water providers in the UK have a legal requirement to disinfect drinking water supplies. This is to make sure that the water is clean and free of any bugs or other contaminants that could make you unwell.

Most of our water comes from surface sources, such as rivers, upland and lowland reservoirs. As rain falls and washes overland into rivers and reservoirs, it picks up various materials which can contain large numbers of harmful microorganisms, which need to be removed by treatment and disinfection.

Why is chlorine added to water?

For over 100 years, chlorine has been added to water supplies around the world to make sure it’s safe to drink. Most of our water comes from sources such as rivers and reservoirs. Chlorine is added to ensure that the quality of your drinking water is kept the same all the way from the treatment plant to your home.

How much is used?

Chlorine is first added at the treatment works, then topped up as needed as it travels through the underground mains to your home. It goes without saying that chlorine levels are kept to the minimum necessary to ensure continuous protection and are constantly monitored by us. Typical levels are between 0.1-0.5 mg/l. To help put this into perspective, a swimming pool commonly uses 5 mg/l.

The taste factor

If you've got a sensitive palate, you may sometimes be able to taste or smell the small amount of chlorine in your water. This can be more noticable when there's high demand (for example, when everyone is having their morning shower) as the water will be getting from the treatment plant to your home quicker. Chlorine levels are monitored all year round to make sure your water remains safe to drink. A good tip for reducing the taste is to keep a jug of fresh tap water in the fridge for a few hours, as this will allow the chlorine to dissipate.

Why is aluminium in my water?

Aluminium is one of the most common elements in the earth’s crust and is naturally present in drinking water and food. As part of the cleaning process, aluminium salts are sometimes used at water treatment plants. This process is essential in removing particles and harmful bacteria from the water. This aluminium is removed at the waterworks to below UK standards before it enters the water mains that supply your home. Typical levels in water contribute to only 3% of our daily intake.

How much is used?

Our treatment processes are operated to keep aluminium levels as low as possible, which is well below the UK and European standard. The UK standard for aluminium is 200 parts per billion (µg/l), or 200 millionths of a gram per litre of water. This is set to prevent any potential discolouration of the water in the mains and is not based on any concern for health.

Is it harmful?

In recent years there has been public concern about a possible link between aluminium and Alzheimer’s disease. Medical experts advise that recent studies about such links are too tentative to justify any changes in the use of aluminium compounds and there's currently no proven health risk. The World Health Organisation has also endorsed this view. However, we’ll continue to support any new findings to make sure that your health and wellbeing is never compromised.


What is cryptosporidium?

Cryptosporidium is a microscopic organism that causes a type of gastroenteritis called cryptosporidiosis in humans and other animals. It’s most commonly contracted when travelling abroad, through contact with those carrying the organism or when children come into contact with infected farm animals or faeces. The symptoms of this include diarrhoea, nausea, vomiting and/or stomach pain.

Can it occur in drinking water?

Cryptosporidium won’t occur when water is properly treated. However, unlike bacteria, cryptosporidium survives in an egg-like body making it more resistant to standard disinfection and enabling it to survive for long periods. Outbreaks of cryptosporidiosis related to drinking water are extremely rare in the UK and there has never been an outbreak associated with our water supply.

How to avoid cryptosporidiosis

Like so many things, the best cure is common sense. Always wash your hands thoroughly with soap and warm water before preparing food, after handling raw food, after going to the toilet and after contact with pets or farm animals. Always avoid untreated water and when possible don’t use drinking water or ice in countries that may have unsafe water supplies. Also try to avoid swallowing water in lakes and swimming pools.




Why is there lead in water?

We work tirelessly to supply you with lead-free water. However, if you're living in an older property, you may be connected to our mains water pipes by a lead service pipe where lead can get into your water. It can also get into your water from lead-based soldered joints used on copper pipes or from lead plumbing inside your home.

The Department of Health advises that lead can be harmful if levels are allowed to build up in your body. Therefore, it makes sense to try and reduce the amount as much as possible and to check your pipes to see if you are at risk. particularly if you are pregnant or have young children. For further health advice please contact your GP or call the NHS on 111.

How to tell if you have lead pipes

If your property was built before 1970 you may have lead pipes, homes built after this are more likely to have plastic or copper pipes. The simplest way to check is to find the point where the water pipe enters your home (it’s usually under your kitchen sink or stairs). Scrape the pipe with a coin and if you see a shiny, silver-coloured metal underneath you’ll know it’s a lead pipe. For a detailed step-by- step guide, watch the video below.

I think I have lead pipes, what should I do?

  • Avoid drinking water that has been standing in the pipes for long periods. Simply flush the water by running the cold tap first thing in the morning and when you get in from work for at least two minutes.
  • Only use water from the cold water tap in the kitchen for cooking, drinking and when making up baby formula.
  • Use water filters designed to remove lead, however this should only be used as a short-term measure. 

The best way to get rid of lead completely is to replace your lead pipes. We recommend you always get at least two quotes from local reputable plumbers. If you decide to replace your part of the pipe, we’ll replace our bit completely free of charge.

See if you qualify for the lead replacement scheme. We’re also proud to support the WaterSafe scheme.

Should I get my water tested?

If you discover that you do have a lead service pipe or plumbing in your property, we’re happy to come out and test the water for you. Simply contact us on webchat using the pink button.

How do I know which pipe I am responsible for?

Generally, you're responsible for all of the pipework starting at the boundary of your property. If you aren't sure, more information and a diagram which shows you the property boundaries, are on our responsibilities for water pipes section.


What are nitrates and pesticides?

Nitrates and pesticides are commonly used by farmers and gardeners around the world to ensure bumper crops and pest-free plants. Nitrate is a naturally occurring compound of nitrogen and oxygen that’s present in all vegetation. It’s usually added to plants in the form of manure and chemical fertiliser. The UK and European standard for nitrate in drinking water is 50 parts per million.

 Pesticide is a broad term for a wide variety of different chemicals including insecticides, herbicides, fungicides and algaecide. All are used in a strictly controlled way that safeguards our farm produce, gardens and greenhouses from unwanted pests. The UK and European standard for pesticide in drinking water is a rightly stringent 0.1 parts per billion.

Can they contaminate my water?

It’s possible for nitrates and pesticides to enter groundwater sources by filtering through the ground. They can also enter rivers and open reservoirs through surface run-off. To help manage this, we work with landowners, farmers, businesses and the Environment Agency to keep levels to UK standards and use our collective ideas to come up with innovative alternatives.

Planning for the future

In the few areas where raw, untreated water has higher nitrate levels; we've developed other lower nitrate sources and blended the two to dilute the concentration. We've also put plans in place for installation of nitrate removal plants as a further measure to make sure the your water is wonderful for many years to come. Furthermore, we continue to work with farmers in order to keep our position as industry leaders in catchment management.


What exactly are biofilms?

Every surface in the enviornment around us will have small organisms like bacteria, moulds and fungi. Biofilm is the name given to layers of these organisms. These are invisible to the naked eye, but can sometimes result in a gunge on your grout, around your taps and on tiles. Biofilm is a very common problem, especially in warm and damp areas such as kitchens and bathrooms. They do like moisture, but don't come from the supply itself.

Are they harmful?

They're rarely more than a nuisance, and are usually caused by poor ventilation rather than uncleanliness. A lot of microbes and bacteria are harmless in most cases, and can even be helpful. However, it's not a good idea to allow large amounts of them to grow. Higher amounts of biofilms can infect cuts or open wounds, and some can cause allergic reactions. Most often, they only cause annoyance with that gunge we have all seen before.

How do I get rid of biofilms?

By using household disinfectant sprays and wiping with a cloth the biofilms should be easily removed. Any staining can be removed using bleach, unless the biofilms are on soft surfaces such as silicone sealants. Using an acidic based cleaner, and even lemon juice can work well, removing the biofilms that you can see.  

To help prevent them from returning, keep the areas well ventilated and dry.

You may also find biofilms in your washing machine drawers and drum. To help stop this from forming, running the machine at 60°c or above once a week kills the microbes and reduces the growth. By leaving the drawer open after you do some laundry, will allow it to dry out between loads.



Filtering out impurities

The water we supply is clean, safe and wonderful to drink, but you can use water filters at home to remove any harmless residual substances from your water such as chlorine and temporary hardness. The simplest filter to use is a jug filter, which uses easy to change cartridges to remove impurities. It’s recommended that these are kept in the fridge and you use the water within 24 hours. The other kind are plumbed-in filters, which are permanently installed into the cold water supply pipe or main supply feed to the taps. In both cases, filters must be strictly maintained according to manufacturer's instructions.

Why use water softeners?

Water softeners are sometimes used by people living in hard water areas to help prevent the build up of scale in their boilers, dishwashers and kettles. When you have a water softener fitted, it’s strongly recommended that you keep an unsoftened water supply for drinking water. This is because the softening process can cause higher amounts of sodium to be in the water supply.

We don’t currently soften any of our water supplies at Severn Trent.

When should soft water be avoided?

It’s important to avoid using ion-exchange softened water for babies feeds, when giving to young children, or for if you are on a low sodium diet. This is due to the increased sodium content from the softener. It’s strongly recommended by medical and plumbing experts that a separate supply is kept for drinking water, as an alternative to the softened supply. We also recommend you use unsoftened water for watering plants and topping up steam irons.