The pets in our families often use water just as much as we do, yet the tap water we give our pets has added chemicals that have more severe affects on them than they do on us. For example, the chlorine present in tap water can kill off many helpful bacteria in animals' stomachs and can even lead to cancer in some pets. Like humans, most animals are around 70% to 80% water and even a 10% loss of water can cause serious illnesses for cats and dogs. This means that quality drinking water is just as important for your pets as it is for you. Bottom line: If you wouldn't drink the tap water, why would you give it to your pet?