How do you build a water filter?

The equipment that you need

  • A wooden crate or similar support (to place the sand filter on)
  • The top of a plastic bottle with lid
  • A pen/marker
  • A 20 litre jerry can that has not been used for kerosene or petroleum products
  • Two clean buckets
  • About 20kg of sand
  • About 3-5kg of pebbles/small stones/ gravel
  • A drill or other means to make the hole in the jerry can (see step 2 below)
  • Cotton cloth
  • One plastic bottle
  • One clear plastic or glass bottle
  • A stick
  • Plastic funnel

How to build the filter

  1. Mark out eight equally spaced lines on your jerry can (each a section)
  2. Insert a hole in the front bottom edge of the can (see the picture above)
  3. Insert the cut off top of the plastic bottle into the hole
  4. Find some pebbles/small stones/gravel (6-10mm wide) then wash them thoroughly
  5. Find sand, preferably from a quarry rather than a river bed. If the sand is from a river bed then try to use sand that is further up the bank
  6. Fill the jerry can in the following ratios: Gravel – 1 section; Sand: 6 sections, Air: 1 section

Maintaining the filter: do this once a month

  1. Put the lid on the top of the jerry can
  2. Turn the jerry can upside down
  3. Take the bottle neck out
  4. Take the lid off the top of the jerry can and quickly put cloth over the hole to prevent the filter materials falling out
  5. Pour in one litre of previously filtered water
  6. Throw away the water once it has passed through the filter
  7. Remove the cloth cover and quickly put the lid back on the jerry can, reinsert the bottle neck and turn the filter the right way up
  8. Continue using as normal for another month