"It simply cannot be overstated how important water is to your dog's health and well being," says Dr. Jon. It helps digest food, absorb nutrients, flush out waste and control body temperature. Next to oxygen, water is the most important nutrient in your dog's body.
According to Dr. Jon, dogs can go for days without food. Their bodies can lose all their fat and up to half their protein and still survive. But when a dog loses just 10 percent of his body's water, bodily functions shut down causing serious illness. A 15 percent loss of body water will kill him.
So how much water does your dog need?
There is no steadfast rule. In general, animals should take in two and a half times more water than food. Another useful guideline for dogs weighing 20 pounds or less is that they need about 1 cup (8 ounces) of water for every 5 pounds of body weight. So, a healthy 15-pound dog would need 3 cups of water a day.
Check your dog's water dish regularly. When fresh, clean water is available a dog will generally drink all he needs to survive. The fresher the water, the more appealing it will be to your dog.