Water constitutes two thirds of the worlds surface and two thirds of your body. Ideally we need to drink at least eight glasses of water. Unfortunately we typically use harmful drinks as sources of our water input. Other than simple soda water and tonic water all soft drinks are harmful for your health. Either they are full of sugar or they have sugar substitutes which are even worse.
Coffee is another drink which is quite bad for one's health.
Excessive alcohol is the last harmful drink. Freeze fruits or buy frozen fruit and add this to water and blend in a blender. If you prefer the fizziness of sodas add club soda or tonic water. As far as the water is concerned use filtered water either by use of a water filter system or buy filtered water. Drink fruit juices.