The construction and functions of a simple water filter to produce clean drinking water is being shown in the following picture.
Overall, it can be seen that tap water has to go through a variety of layers in order to become clean and fresh.
Firstly, the water will be poured into a plastic barrel containing multiple layers at the bottom. The water will then flow through sand, charcoal and gravel respectively until it reaches the end of the barrel. One side of a small, long tube will be placed at the lowest layer of that plastic barrel, which is the above storage drum, connecting it with another storage drum through a hole in the barrel.
After being filtered through all three layers, the water will be tranfered and stored into the storage drum through the tube. The clean and fresh water can now be drawn out to drink by using the faucet at the end of the drum.