A severe drought affects those people because they don't have access to a water source in a dry plain. It would be harder to find fresh water because the climate causes the area to be hard, dry and dusty. This makes them more reliant on taps and water sources they have not to break. The United States is a notoriously hot country, by hot, I mean warm and some states are especially dry and dusty. These types of land can cause drought braise water can be evaporated by the suns heat. A severe drought would make a lot of people dehydrated as access to an open water source without taps would be extremely difficult.