Why is water so important for our body? Because water is a vital component of our body, since 50-60% of body mass consists of water. To be healthy, we must drink 6-8 glasses of water (fluids) a day. It doesn’t have to be only water, milk, herbal teas and juices without sugar count as well. When it’s hot, and particularly when you are physically active, additional intake of fluids is necessary.