Water makes up 80% of our brains, so it's important that we drink enough of it to be able to concentrate.

So if it's hot outside, or your class has been exercising hard, you should be regularly topping up your water levels.

Not only is water better than high calorie, fizzy pop, it's also much cheaper and available on tap.

Water is one of nature's greatest gifts. It falls from the sky as rain before finding its way into rivers or sinking into the ground. Eventually it returns to the sea, where it evaporates, forming rain-clouds and the whole cycle starts again.

The water cycle is very important to us here at Yorkshire Water, as it enables us to provide two million homes and businesses in Yorkshire with fresh drinking water every day. Here you can find out more about how we make water work for you:

How we collect water

Considering the water cycle is truly a cycle, there's no real starting point, but if we had to pick somewhere to begin our exciting journey we'd probably say the sun.

Before we can extract the water from rivers, reservoirs and boreholes there are three main steps in the cycle - evaporation, condensation and precipitation:


The sun heats up the water from the oceans where it evaporates and rises into the air as water vapour. The vapour then rises into the earth's atmosphere, along with water transpired from plants and evaporation from the soil. Ask your pupils to think about what happens to a puddle when the sun comes out.


As the water vapour rises, the colder temperatures cool the vapour so that it condenses to form water droplets in clouds. Clouds are formed when water droplets and pieces of dust join together in the atmosphere. If it's warm outside ask your pupils to think about why water forms on the outside of a glass when you pour cold water into it. If it's a cold day you could always ask them why water droplets appear on the inside of the window.


As the water vapour condenses the air can't hold it anymore so it falls back to earth as rain, sleet, snow or hail. The word precipitation comes from Latin and means "falling". Try asking your pupils to remember the name of this process the next time it rains.

Water treatment

A lot goes on at our water treatment works to make your water safe for drinking. The extent of the treatment varies depending on where we collect the water from - if it's from a borehole the water usually only requires minimal treatment, if it's from lowland river sources and upland reservoirs it will go through a tougher treatment process.

When water reaches our works it will normally go through the following stages to remove the "baddies":


The water passes through a huge metal strainer to remove debris like leaves and twigs.


Approved chemicals are added to act like a magnet for smaller impurities like dirt, natural colour and bacteria. The chemicals form a sort of jelly called floc.

We've developed an interactive guide to water treatment including cool sound effects and animations. Pupils can follow a gang of baddies on their doomed journey through the water treatment works.


The floc has to be taken out of the water, so air is bubbled through the tanks to make the floc float to the surface to form a blanket, where it is scraped off. This process is called Dissolved Air Flotation or DAF for short. At some works that don't have DAF, the floc instead sinks to the bottom of the tanks and is taken away - this process is called sedimentation.


The clarified water is passed through filters filled with layers of sand and gravel to remove any final traces of the floc and metals such as iron and manganese. These filters are cleaned regularly, every one to two days.


Ozone is a gas which is a powerful oxidant and is used at a few of our water treatment works. It is bubbled through the water to remove any traces of pesticides or similar compounds.

Granular Activated Carbon

Granular Activate Carbon is used in filter beds to remove the by-products of ozonation, as well as traces of any other substances which may also be found in the water.


Chlorine is then added to the water. This kills off any microbes that may still be present. A small amount of chlorine is left in the water as it travels to your home to ensure the water at your tap is of the highest possible quality.

We've only given you the basics of water treatment here. If you'd like to know more about how you can include this subject in your lesson plans, download our Science Pack - there are exciting water facts and fun, interactive experiments.

Water distribution

Having removed the "baddies" from the water we've collected it's now ready to be delivered to the homes, businesses and schools across Yorkshire.

We do this using our Yorkshire Grid which allows us to transfer water from one part of the region to another depending on where it's needed most. This means that, come rain or shine and wherever you are in Yorkshire, you can be assured that your water will always be on tap.

The grid also means that that the water your pupils drink at school has not necessarily come from the nearest source, it may have travelled several miles before it reaches them. Think of it like one giant water vending machine that never runs out of their favourite drink!

Collecting and treating waste water

How we treat Yorkshire's waste water

Getting water into your home and school is only half the story. Once it has been used, it's up to us to collect and treat Yorkshire's waste water and return it safely to the environment.

Collecting waste water

We have a network of around 20,000 miles of underground pipes, collecting the raw sewage from the region's homes, liquid waste from industry, and rainwater that falls on roofs and roads. After water's been used, it enters a waste pipe, travels into a drain, then into a sewer pipe that joins others to form something we call a trunk sewer.

Eventually it reaches one of over 600 waste water treatment works across the region where we improve the water before putting it back into the environment.

Treating waste water

At our treatment works the waste water goes through six key stages before it's good enough to be released into rivers and the sea:

1. Screening

We remove debris and large objects such as wood, rags, paper and plastics by passing the waste water through specially designed metal grids called screens.

2. Primary treatment

Sewage is transferred into large tanks called settlement tanks where most of the remaining solids sink to the bottom forming sewage sludge. The sludge can either be composted to improve soil quality, burned in an incinerator or digested by special bacteria to produce gas which can be burned to generate electricity - poo power as we like to call it.

Discover more about poopower in the classroom - download our guide to how human waste can help generate electricity. Key stages two and three.

3. Secondary treatment - stage one

The liquid sewage flows on to stage three which involves biological treatment. Here, the sewage is trickled over filters of stone containing billions of "goodie" micro-organisms which feed on the "baddies" and remove any organic pollutants.

4. Secondary treatment - stage two

Sometimes the sewage is mixed with the micro-organisms in a tank.  Oxygen is bubbled into the tank so that the "goodies" can breathe and go to work.

5. Final treatment

Finally, the sewage enters our settlement tanks where any remaining micro-organisms and sludge sink to the bottom. At coastal sites we also zap the waste water with ultra-violet light to kill of any surviving bacteria.

Returning water to local rivers and sea

It's important for our environment that the water we use is returned safely to the rivers and the sea. Many of our rivers are cleaner now than since the industrial revolution over 100 years ago. This is because we've been hard at work updating and modernising many of our waste water treatment plants in the region.

We also play a massive part in improving Yorkshire's coastal bathing waters thanks to a multimillion-pound investment in our waste water treatment in these areas.

To see how we're encouraging biodiversity and putting rivers back at the heart of communities in Yorkshire visit our Biodiversity page.

If you'd like to learn more about how we're helping keep Yorkshire's coastal waters clean, take a trip to the seaside.

We’ve all heard and used the sayings ‘Where there’s muck there’s brass’ and ‘Muck for luck’. They infer that from something dirty you can gain wealth or a benefit.

Well, Yorkshire Water is taking this idea on board literally by taking this idea on Poo Power to generate electricity at waste water treatment plants.

With the rising costs of gas and electricity, we see Poo Power as a renewable source for locally generated electricity, with the ability to reduce fuel bills, manage our business sustainably and reduce their carbon footprints.

Poo power facts

Poo Power uses a biogas rich in methane which is extracted from the treatment of waste water and sewage to drive turbines. The biogas, predominantly comprising of methane, is produced when bacteria feed on human and animal waste. This process is known as anaerobic digestion and it is a great way to produce green energy, as well as getting rid of waste and the microorganisms that lurk in it. One of the simplest ways of describing anaerobic digestion to young people is the ‘farting’ of millions of tiny bugs within the waste, which produces the biogas.

Positively, when the biogas is burnt for generating electricity, far less carbon dioxide is released than when fossil fuels are burnt. However, it is useful to note that using biogas in this way does have its limitations in that it takes the poo of 100,000 people to generate 51kWh of electricity; enough for 3,000 to 5,000 LED/energy saving light bulbs.

Poo Power is not a new thing. Animal and human waste has been used as a source of energy for many years in countries around the world where electricity and gas are scarce. Small biogas plants are common in South East Asia and Africa, where animal dung is used as the fuel. In Australia, pig excrements are used to power farms and chicken poo has been used for generating electricity in the UK.

The use of human waste to generate electricity in more developed countries is relatively new. The use of Poo Power at waste water and sewage treatment plants has already been mentioned, but even the London Science Museum is planning to turn the waste it gets from its 3 million visitors a year into electricity. The processed waste could produce as much as 1,530 kilowatt hours of electricity a year.

Poo can also be used to heat homes. In Norway, householders are now heating their homes and offices by flushing the toilet. The sewage heat pump plant uses fridge technology to tap heat from raw sewage. Machines at the end of a 300-metre-long tunnel in a hillside in central Oslo suck heat from the sewer and transfer it to a network of hot water pipes, feeding thousands of radiators and hot water pipes in the city. It is believed to be the biggest heating system in the world using raw sewage.

At Esholt, we have built some new Poo “cookers” called Thermal Hydrolysis tanks, which generate enough energy to power 7,000 homes a year!

Read about our new Esholt plant and more about what we are doing to reduce our carbon footprint by clicking the following link:

Reducing our carbon footprint

Water makes up 80% of our brains so it's important that we drink enough to be able to concentrate - especially in class! Yorkshire Water will provide you with everything you need to know to understand water and health.

Children should regularly top up their water levels, particularly if it's a sports day or the weather is hot. Not only is water better for them than those high calorie fizzy drinks, it's also much cheaper and available on tap!

Are you drinking enough water?

When it comes to drinking water, we recommend the recommend the folowing advice:

1. Children and adults should drink between six and eight glasses of water every day.

2. Children will need more water when exercising - to keep them properly hydrated they should drink slowly at 10 -15 minute intervals to replenish any water lost through sweat and continue drinking water after exercising. 

3. Lack of water can affect a child's performance so if they're tackling a really tricky equation it might be worth getting them a drink first!

4. Children will love this one - the colour of their wee may indicate that they are dehydrated. They can keep a check on the colour of their urine to make sure they're drinking enough water using our fun peeometers.

There are three main dangers - strong currents, the cold and time

Strong currents - these lurk beneath the surface, particularly if water is being taken out through massive pipes beneath the surface.

The cold and hyperventilation - when fatalities occur, it's the temperature of the water which is often the most significant factor. Reservoirs are deep and the water in them doesn't flow like in rivers or the sea so the temperature rarely rises much above 12 C.

Immersion is enough to take most people's breath away but what they probably don't realise is that this sensation is their body's natural defences kicking in - and they will only protect a swimmer for a matter of minutes, no matter how confident they are in the water.

One of the first signs of trouble is hyperventilation as the body tries to increase the flow of oxygen into the blood to help stave off the cold but, if the swimmer remains in the water, the body will begin to shut down to protect the vital organs. Muscles will go into cramp and suddenly it's no longer possible to swim. The victim will try to fight to stay on the surface but, if help doesn't arrive within seconds, they will be drawn unavoidably underwater, even though they may still be fully conscious and aware of what's happening.

Time - even if friends or relatives dial 999 within minutes of a swimmer disappearing, the reality is that the emergency services are more likely to be dealing with the recovery of a body rather than a rescue.

Firefighters, police and paramedics may be able to reach the scene within minutes, but if the victim is still somewhere in the water, they'll not be able to begin a search until specialist equipment arrives. Instead, they can only watch and wait, which may be hard for onlookers to understand but is often as traumatic for the emergency services as for family or friends of the missing swimmer.

It can take days to recover a body from a reservoir. In the meantime, friends and loved ones can do nothing more than return home and begin a tortuous wait for news.