Water scarcity is when there is not enough clean water for people, animals, and plants. It can happen when there isn't enough rain to fill rivers, lakes, and other sources of water, or when people take too much water from these sources and use it up. When there isn't enough water, people, animals, and plants don't have enough to live on. This can make it hard for people to get enough fresh water to drink and for farmers to grow the food we need.