A basic water filter can be made with ordinary materials:

• ROCKS filter out large particles like twigs, leaves and insects.
• SAND provides mechanical filtration and removes small, fine contaminants.
• CHARCOAL uses absorption to remove even finer impurities in the water.
• CLOTH is another mechanical filter. Cloth can also be used between layers

The fundamental concept of this water filter can be expanded to meet a larger demand: putting all layers in a 5-gallon bucket or using a bucket foreach layer and connecting them.

1. The first level consists of gravel to remove larger solids, such as leaves, twigs, bugs and debris that might be in the water.
2. The second layer is sand, which will remove floating and dissolved particles of solids as the water passes through it.
3. At this point, all that is left to be a problem is the microscopic pathogens, which are reduced by over 99 percent by the final layer, that of activated charcoal.