How much water pets need
A healthy dog needs about 50 to 60 mL of water per kilogram of body weight each day, which is close to the familiar rule of 1 fluid ounce per pound. Cats need a little less, about 40 to 60 mL per kg. This calculator uses 60 mL/kg for dogs and 50 mL/kg for cats.
That total includes the water in food. Dry kibble contains about 10% water, while wet food is 75 to 80% water, so a pet on wet food drinks much less from the bowl.
Worked example
A 50 lb dog eating dry kibble:
- Weight: 50 lb = 22.7 kg.
- Daily need: 22.7 × 60 = 1,361 mL, about 46 fl oz or 5.8 cups.
- On kibble, almost all of it comes from the bowl: 46 fl oz.
- Drinking more than about 77 fl oz a day (100 mL/kg) would be considered excessive.
Typical daily needs
| Pet | Weight | Water per day |
|---|---|---|
| Cat | 10 lb | about 8 fl oz (1 cup) |
| Small dog | 15 lb | about 14 fl oz |
| Medium dog | 40 lb | about 37 fl oz |
| Large dog | 70 lb | about 64 fl oz |
When to worry
Drinking too much (polydipsia), more than about 100 mL per kg a day, can be a sign of diabetes, kidney disease, Cushing’s disease, an infection or a medication side effect. Drinking too little can lead to dehydration, especially in cats, which are prone to urinary problems.
Call your vet if your pet:
- suddenly drinks or urinates much more than usual;
- has sticky gums, sunken eyes or skin that stays tented when pinched;
- vomits, has diarrhea or refuses water for more than a day.
Helping pets drink enough
- Keep fresh water available at all times and clean the bowl daily.
- Bring water on walks, hikes and car trips, and offer more after exercise and in hot weather.
- For cats, try a water fountain, wide shallow bowls placed away from the food and litter box, and some wet food.
This calculator gives general estimates for healthy animals. It does not replace the advice of a veterinarian who has examined your pet.