The given diagram illustrates the steps of turning contaminated water into drinkable water by a water-filter system .
Overall , it is clear that the system of filtration consists of two barrels made of plastic and covered with a plastic lid , one for water purification and the second for storage .
First of all , dirty water is poured into the barrel which contains sand , charcoal , and gravel at the bottom . Then water passes through these three layers responsible for purification . Next , water is pumped upward via pipe to the storage drum , it is important to notice that purification barrel is located above the storage drum .
Finally ,clean drinkable water is stored in storage drum contains tape at the end until it is used .