According to smalldogsparadise.com, small dogs need 8 oz. of water per 5 pounds of weight. Shih tzu puppies are very small, often only 2 to 3 lbs. According to this rule, a 2.5-lb. puppy would need approximately 4 oz. of water each day.
Different shih tzu puppies will need different amounts of water, smalldogsparadise.com says. High levels of activity drive up the needed amount of water. Puppies on a dry food diet also will need more water.
Your puppy knows when it needs water. Keep your puppy's water dish clean and full of clear water, and your puppy will drink water whenever it feels the need, according to allshihtzu.com.