The Clearest Water

Make a water filter


The Clearest Water is a chance to have a go at filtering water.

Global Picture

All over the world, people have to filter their water to make it safe to use. In the UK this is mostly done by big processing centers. In poorer and more rural parts of the world, it’s done in individual villages and households. Whatever the scale, all of the methods involve filtering the water to remove large and small impurities.

The Clearest Water

Let’s make a filter and see how clear we can get the water.

  1. Find a source of muddy water. It could be from a puddle, or a stream, or you could make your own by mixing some dirt into a bottle of tap water.
  2. Take the large bottles and cut the bottom 6 – 10cm off. Keep hold of it for later.
  3. Remove the bottle top, cut a piece of material and use an elastic band to secure it over the mouth of the bottle.
  4. Turn the bottle so its cut side up and the bottle and drop layers of your filter materials into it. Start with the smallest things, like sand. And work up to the larger things like pebbles.
  5. Once you have put all your filter materials in your filter is complete. Holding it over the base that you cut off, you will use this to collet the filtered water.
  6. Pour the dirty water in at the cut end of the bottle and watch it move through. How quickly does it flow?


Filtered water is not pure, as there are probably still organisms too small to see and be trapped by the filter. So don’t drink it.

Be careful if collecting water from a stream.  Pick a site that is likely to be as clean as possible, for example avoid areas of agriculture where faeces and pesticides may be an issue, or areas where poisonous plants may be growing.

Take It Further

If you enjoyed creating the clearest water, why not try making Eco Bricks from your waste plastic, or foraging for elderflowers and making elderflower cordial.

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