If earth has so much water, why do people in some areas have none to drink. explain?

Although there is alot of water on earth some of it is contaminated and could be harmful for us to drink .Therefore people don't drink it in order to not get sick.

Firstly, the water in the dams hold gravitational potential energy as they are above ground level. the gravitational potential energy is then transferred to kinetic energy as it falls, spinning the turbinethe turbine then spins the generator, which is a large magnet surrounded by metal coils. by doing this, the generator generates electricity. in this action, the energy transfer taken place is kinetic to electric energy