Where does our water come from?
We take water from lots of sources. Around half the water we supply comes from moorland reservoirs, a quarter from rivers, and a quarter from underground boreholes and spring sources.
What standards does our drinking water have to meet?
The quality of drinking water in Britain is controlled by some of the tightest regulations in the world, with standards set by the European Commission for over 50 different substances. The UK government has added extra standards to protect public health. Not all standards are about health, some control the taste and look of water. The Drinking Water Inspectorate (DWI) independently monitors our operations and advises the government on our performance in all aspects of drinking water quality.
To find out more, visit dwi.gov.uk.
How do you make sure our water meets these standards?
To make sure the water we supply your home meets the government’s high standards, we regularly take samples from our treatment works, service reservoirs and customers’ taps for testing. We test over 500,000 water samples every year! We also carry out operational checks, using state-of-the-art technology and laboratory techniques, to make sure your water is the best possible quality.
The Drinking Water Inspectorate (DWI) then looks at the results from these tests and creates an independent report on its findings.
How do you test water from customers taps?
To make sure all our customers are getting great quality water, we do home water quality inspections. These are spot checks and we randomly select addresses from each of our supply zones.
To test your water quality, we get samples of water from your main feed, this is usually the cold water tap in your kitchen. We take these samples away for testing.
What do you test drinking water for?
Our water samples are tested for over 50 substances!
Colour
The colour of our water is affected by naturally occurring organic matter in the soil which runs off moorland into our reservoirs and rivers. This standard is set so the water looks good and needs to be virtually colourless.
The colour of drinking water needs to be 20mg/l Pt/Co scale (Hazen units).
Turbidity
Turbidity measures the cloudiness of the water. Sometimes tiny air bubbles can make water look milky, this isn’t harmful and will clear if left to stand for a few minutes.
The standard for turbidity at your tap is 4.0NTU.
Taste and smell
Our water goes through quality control tests and is tasted by a specialist panel.
The taste and smell needs to be acceptable to our customers with no abnormal changes.
Hardness
This measures the hardness of our water. The higher the hardness, the more soap is required to form a lather. High hardness waters are typically from chalk and limestone; low hardness (soft) waters from moorland.
There's no specific standard for hardness.
Conductivity
Conductivity measures the amount of salts in water. If levels are higher than the standard, it can affect the taste of water and corrode pipes.
The standard for conductivity is 2500µS/cm.
pH (Hydrogen ion concentration)
This measures how acidic or alkaline the water is. Water supplies in our area are usually slightly alkaline which helps to prevent corrosion of pipes and fittings.
The pH of drinking water needs to be in the range of 6.5-9.5.
Nitrate
Nitrate comes from fertilisers used in agriculture and we treat the water to remove it.
The standard for nitrate is 50mg/l.
Nitrite
Nitrite is created when chloramine is used to disinfect the water. Chloramine stays in water longer than chlorine and helps reduce microbiological activity.
The standard for nitrite is 0.5mg/l.
Aluminium
Aluminium can occur naturally in water. Aluminium is also used at some treatment plants to remove impurities and is then removed.
The standard for aluminium is 200µg/l.
Iron
Iron occurs naturally in many water sources. Iron is also used at some treatment plants to remove impurities and is then removed. Iron may also find its way into water when pipes corrode.
High levels of iron can make your water look different.
The standard for iron is 200µg/l.
Manganese
Manganese occurs naturally in water, high levels of it can make your water look different.
The standard for manganese is 50µg/l.
Copper
High levels of copper may be caused by copper plumbing and fittings in your home. High levels of copper can cause a metallic taste or a blue tint in water.
The standard for copper is 2mg/l.
Fluoride
We don’t put fluoride into Yorkshire’s water, but fluoride can occur naturally in your water.
The standard for fluoride is 1.5mg/l.
Lead
Lead can naturally occur in water, but it’s rare in the UK. Our water mains aren’t made of lead and we test our water at every stage of the treatment and distribution process to make sure it meets our strict drinking water standards.
The pipes that supply water to your home and the plumbing inside your house may contain lead. If water is left to stand in lead pipes, it absorbs small traces of the metal. If you’re exposed to too much lead it can be harmful to your health.
The standard for lead is 10µg/l.
Chloride
Chloride occurs naturally in most water sources. If levels are higher than the standard, it can affect the taste of water and corrode pipes.
The standard for chloride is 250mg/l.
Trihalomethanes
Trihalomethanes are formed when chlorine added to disinfect the water reacts with naturally occurring organic substances.
The standard for trihalomethanes is 100µg/l.
Chlorine
We add chlorine during treatment to disinfect water and make sure it’s free from harmful bacteria. We carefully calculate how much to add, so by the time it reaches your tap, you won't be able to taste or smell the chlorine.
There's no specific standard for chlorine.
E.coli and Enterococci
E.coli and Enterococci are bacteria that form in the digestive systems of animals.
If we find them in treated water, it can be a sign of contamination by faecal matter and more harmful bacteria may be in the water. Any detection of E.coli and Enterococci are investigated as a matter of urgency.
The standards are 0 per 100 ml.
Coliforms
Coliform bacteria occur naturally and we remove them when we treat the water. They're not likely to be harmful. If they're found in treated water, it tells us the water may be contaminated, possibly from the tap. We always carry out immediate investigations if we find coliforms in treated water.
The standard for coliform is 0 per 100ml.
Clostridium perfringens
Clostridium perfringens are bacteria that form in the digestive systems of animals. They create spores that can stay in the environment for a long time. They're not likely to be harmful and if they're found in water it's because of past contamination. We always carry out immediate investigations if we find clostridium perfringens in treated water.
The standard for clostridium perfringens is 0 per 100ml.
Colonies
Colonies are naturally occurring bacteria and aren't harmful. If we find unusually high levels in our water, we'll investigate.
There's no specific standard for colonies.
Cryptosporidium
Cryptosporidium is a tiny microorganism that can sometimes cause an illness called cryptosporidiosis. Cryptosporidium can come from many other sources, not just water. At our treatment works, we monitor our water for cryptosporidium. If we find any, we investigate and report it to the Drinking Water Inspectorate.
There's no specific standard for cryptosporidium.
Other substances and compounds
| Parameter | Standard |
|---|---|
| Sulphate | 250mg/l |
| Sodium | 200mg/l |
| Ammonium | 0.5mg/l |
| Total organic carbon | No standard |
| Antimony | 5µg/l |
| Arsenic | 10µg/l |
| Boron | 1mg/l |
| Cadmium | 5µg/l |
| Chromium | 50µg/l |
| Cyanide | 50µg/l |
| Mercury | 1µg/l |
| Nickel | 20µg/l |
| Selenium | 10µg/l |
| Gross alpha | 0.1Bq/l |
| Gross beta | 1.0Bq/l |
| Total pesticides | 0.5µg/l |
| Individual pesticides | 0.1µg/l |
| Aldrin, dieldrin, heptachlor and heptachlor epoxide | 0.3µg/l |
| Metaldehyde | 0.1µg/l |
| Polycyclic aromatic hydrocarbons | 0.1µg/l |
| Benzo 3, 4-pyrene | 0.01µg/l |
| Bromate | 10µg/l |
| Tetrachloromethane | 3µg/l |
| Benzene | 1µg/l |
| 1, 2 Dichloroethane | 3µg/l |
| Tetrachloroethene + trichlorethene | 10 μg/l |
Do you add fluoride to our water?
No, we don’t put fluoride into Yorkshire’s water. Any fluoride in your water occurs naturally.
Is there lead in my drinking water?
Lead can naturally occur in water, but it’s rare in the UK. Our water mains aren’t made of lead and we test our water at every stage of the treatment and distribution process to make sure it meets the strict drinking water standards.
If you live in an older house, the pipes that supply your water and the plumbing inside your home may contain lead. If water is left to stand in lead pipes, it absorbs small traces of the metal. If you’re exposed to too much lead it can be harmful to your health.
Does water quality vary?
The taste, colour and hardness of your water depends on the source of your water supply. You can use our postcode checker to find out where your water comes from, what’s it in and how hard or soft it is – very useful if you’re buying a new washing machine, dishwasher or even tea bags!
Find out what's in your water
What are you doing to improve water quality?
We're currently upgrading our water treatment works and network of pipes to lower the risk of discoloured water and leakage.
Why do we need to upgrade the water mains?
Our network of pipes is huge and some of it was laid in Victorian times - so there’s always pipes in need of some TLC! When older pipes corrode, natural minerals can build up in these pipes and cause low pressure or funny coloured water. By upgrading these pipes we’re giving our customers a more reliable, top quality drinking water supply.
How do you improve the water mains?
We use the following techniques (or a combination of them!) to make sure our pipes are up to scratch:
- Replacing pipes – if the water mains are beyond repair, we replace them with new durable plastic pipes. If the new main is going to supply your home, a service pipe will be laid up to the boundary of your property.
- Cleaning pipes - if the pipes are in good condition, we simply clean them to remove the natural minerals that cause low pressure or funny coloured water.
- Relining pipes - if the pipes are in poor condition, we reline them with a protective coating. Once the lining is hard, we disinfect the pipe and take water samples to make sure it's safe.
Can I improve the water quality in my home?
Yes, you can! Here are our top tips to improve your water quality:
- Keep kitchens and bathrooms well ventilated to prevent the build-up of moulds and stains on tiles and other surfaces which are often in contact with water.
- Run off any water which has stood in your pipes overnight before the water is used (very important if you have lead pipes). Save this water for houseplants or your garden.
- Look out for an approval logo on all plumbing materials, this means they’ve been approved and will minimise taste, smell and discoloration problems.
- Ensure hot water pipes aren’t too close to cold water pipes to prevent cold water pipes becoming warm, which can lead to water developing a cloudy appearance due to the presence of air bubbles.
- Inspect water tanks and other storage tanks regularly, checking for adequate covers, vents and ventilation to help prevent tastes, smells and slimes.
- Always use an approved plumber with a good reputation. To find an approved plumber visit the WaterSafe website.
Can slug pellets affect water quality?
Yes, when it rains, slug pellet residue containing Metaldehyde can be washed into our water supply.
Thankfully, current residue levels are so small, there's no risk to health but they’re above the level allowed by UK and EU legislation. We'd like your help to keep the level of Metaldehyde as low as possible.
Do
- Check if you’ve got slugs on your land before using pellets - set slug traps using a tile with chicken mash layers underneath.
- Buy some slug traps which use stale beer or a yeast solution from your local garden centre to protect your garden. These attract slugs and reduce risk of damage to plants and the need for pellets.
- Use good quality wet process pellets with lower strengths - they may cost a little more, but they stay as a bait for longer before washing away. Pellets with 3% and even 1.5% metaldehyde have proven to be just as effective as those with 4- 5%.
- Use the minimum dose possible as advised by your agronomist and the product packaging
- Try using ferric phosphate pellets -they’re great at killing slugs and won’t affect our water.
- Check the calibration and operation of pelleting equipment before use.
Don't
- Apply slug pellets when heavy rain is forecast.
- Apply slug pellets if field drains are flowing.
- Apply slug pellets within six metres of water courses or ditches.
- Use pellets containing 6% metaldehyde.
- Clean your applicator in the yard - clean it in a field away from margins, ditches and watercourses.
- Use slug pelleting equipment unless you’re trained and have approval.
For more information and best practice advice go to getpelletwise.co.uk*
*'Get Pelletwise' is the campaign of the Metaldehyde Stewardship Group (MSG) that was set up in 2009 in response to analysis showing traces of metaldehyde across various parts of the UK. It’s made up of representatives from Water Companies as well as representatives from the agricultural and agri-chemical sectors.