On average, an American uses approximately 100 gallons of water a day, but Americans could use less. So if we use all that water, where does it go when we use it? Why do we need water? Water is used when we flush the toilet, wash our hands, take a shower, wash the dishes, and as well as drinking water. So that people like you and me are not affected, how does water scarcity affect others? Some people that lack water cannot be as healthy by the inability to wash themselves/hands, etc. and as well as not being able to stay hydrated. This has already started in places like Africa.