Water Supply

In this zone you will think about how important the water cycle is and become a weather-watcher, measuring the amount of rain that falls. You will discover how water is made safe to drink, you can make your own water filter and find out more about water and light. Once we have treated the water to make it safe, we need to get the water to you as you will find out by playing Pipemania!

Water leaves our treatment works in large pipes called water mains, but these don’t come straight to your house as they are too big and the water is under too much pressure. So, first we pump the water to large tanks called service reservoirs – these can be under the ground or at the top of a water tower. Very often they are on high ground so that we can use gravity to help move the water through smaller pipes called distribution mains. Then the water enters smaller pipes to get to homes, schools, hospitals in fact everyone who needs water. Try making your own water tower.

Water Cycle


There is no new water on the earth, we depend on the water cycle for our water.

Water Cycle

The amount it rains varies from month to month and can be very unpredictable. It doesn’t always rain as much as we think it does. Try making your own rain gauge to record your own measurements.

See what the next activity is... Make your own rain gauge

Make a Rain Guage


You will need: Ruler, scissors and an empty 2 litre drink bottle with straight sides.

What to do:

Make a Rain Guage
  1. Cut around the plastic bottle about two thirds of the way up.
  2. Turn the top part of the bottle upside down and place it inside the bottom part of the bottle.
  3. Find a place outside to put your rain gauge, it must be away from trees.
  4. Dig a hole and bury your rain gauge so that the top is sticking out of the ground about 5cm above the ground. This will stop the rain gauge from blowing away on windy days!
  5. Check the rain gauge at the same time every day. Use a ruler to measure the amount of rain collected, then empty the bottle. (Remember to allow for blank spaces at the end of the ruler).
  6. Record your results in a table similar to that below (Or use the link above to download a copy)
Make a Rain Guage

See what the next activity is... Water treatment

Water Treatment


Where the water comes from
All the water we use in our everyday lives at home and at work comes from the natural environment. 85% of it comes from deep under the ground in rocks that can hold water such as chalk – these are called aquifers. When it rains, water runs into streams and rivers and soaks into the ground. In spring and summer much of it evaporates or is used by plants and trees but in winter the rain seeps through the topsoil and into the rock beneath the surface. We use boreholes to pump the water out from under the ground to be treated. The rest of our water comes from our reservoir at Bough Beech, near Edenbridge, which is filled from the River Eden in Kent. We can only fill the reservoir during the autumn and winter months when the river is flowing at the required level.

How water is treated

We have eight treatment works, seven treat water from the boreholes and one treats water taken from a river. Each one treats the water slightly differently because the water passes through different rocks and so contains different minerals or has drained across the land and into the river and has picked up soil and other debris from the land.

Groundwater is high-quality as it has been naturally filtered as it passes down through the rocks. However, it may contain dissolved minerals from the rocks, it all depends on the geology (the type of rock). Some rocks cause the water to have a large amount of calcium salts in them, meaning it is classed as hard water. We can remove calcium salts, in a process known as softening.

River water is treated in a different way as it requires more filtration to remove large solids such as fish and leaves. Chemicals such as fertilisers and pesticides also need removing.

All our treatment works use chlorine to disinfect the water and kill off germs and micro-organisms. Most use some form of filtration, usually sand filtration, to remove fine solids from the water. Some of the treatment works use granular activated carbon to remove dissolved chemicals such as pesticides from the water. We can also use ultraviolet light to destroy the different types of micro-organisms that chlorine doesn’t kill.

See what the next activity is... Make a water filter

Make a Water Filter


You will need: An empty 2 litre drink bottle with straight sides, scissors, sand, cotton wool, gravel, stones and dirty water

Water Filter
Make a Water Filter
  1. Cut around the plastic bottle about two thirds of the way up.
  2. Turn the top part of the bottle upside down and place it inside the bottom part of the bottle.
  3. Use the diagram above to make the rest of your filter. Think about why the materials are in this order.
  4. Pour some dirty water through your filter and look at the water in the bottom.
Make a Water Filter

See what the next activity is... Build a water tower

Build a Water Tower


METHOD 1: Using nets
You will need: paper, pencil and ruler or pre-printed nets, scissors, colouring pens or pencils and glue.

A net can be folded up to make a 3D shape.

You could use just cubes or a mix of cubes and different shapes to build the tower and maybe even a square-based pyramid for the roof. The design is all yours. Either draw your own nets or download the ones in our download section. Decorate your nets and then cut them out. Assemble each net and then stick them together to make your tower.

Build a Water Tower

METHOD 2: Using rolled paper
You will need: paper, scissors, sticky tape and an empty bottle.

Build a Water Tower

Roll your paper into cylinders. Either wrap them around a pencil or just roll the paper up. A piece of tape at either end should be enough to hold it together, but you may want to add a third piece of tape in the middle. Then build your tower in any way you want but your challenge is to make sure it can hold an empty water bottle.

Build a Water Tower

When your tower is finished you can test to see if it is strong enough to hold the bottle when it is filled with water. Perhaps do this by the kitchen sink!

You could challenge someone else to see who can build the tallest tower - but it must be able to hold a full bottle of water! Remember to drink the water afterwards don’t throw it away!

See what the next activity is... Make a rainbow

Make a Rainbow!


Did you know that light is actually made up of all the colours of the rainbow mixed together to form what we call white light? Light travels as waves and these waves can change direction when they travel from the air into glass or water.

You can prove that light waves are bent (refracted) in water. Just take a glass of water and put a pencil in it and see what happens.

Sir Isaac Newton was the first person to prove that light was made of different colours. He saw what happened when white light passed through a prism. A prism is a piece of glass or other see-through material that has several flat sides, called faces. They can come in many shapes.

Light travels in waves and each coloured light has its own wavelength, this is why the colours in a rainbow are always in the same order. Red light has the longest wavelength and violet light has the shortest wavelength. The shorter wavelengths move faster and have more energy. The order of the colours in the rainbow from the outside to the middle is red, orange, yellow, green, blue, indigo and violet.

Make a Rainbow! Make a Rainbow!
Make a Rainbow!

Ultraviolet light in water treatment

We use ultraviolet light to treat water to make it safe to drink. Any bacteria that get as far as the UV reactors get exposed to the high energy of the ultraviolet light. This breaks down the DNA and stops the bacteria reproducing. DNA is the arrangement of molecules that gives a living organism all the information it needs to live so all living things, including you, have DNA.

Try making your own rainbow!
If it is a sunny day you might be lucky enough to make your own rainbow.

Make a Rainbow!
  1. Take the glass of water and paper to a part of the room with sunlight (near a window is good)
  2. Hold the glass of water above the paper and watch as the sunlight passes through the glass of water, as it bends (refracts) it will form a rainbow on your paper.

If that doesn’t work try using a torch as your source of light. Watch the video below to see another way to make a rainbow.