How much water does a dog need?
A healthy dog drinks about 1 ounce of water per pound of body weight a day, which is 50 to 60 mL per kg. A 40 lb dog needs about 4.6 cups (1.1 liters). Dogs need more on hot days, after exercise and when nursing puppies, and less when they eat wet food, which is about 75% water.
Cups = mL ÷ 237 · Too much = more than 100 mL per kg
Water intake chart by weight
| Dog's weight | Water per day | Too much if over |
|---|---|---|
| 10 lb | about 1.2 cups (9 oz) | 1.9 cups |
| 20 lb | about 2.3 cups (18 oz) | 3.8 cups |
| 40 lb | about 4.6 cups (37 oz) | 7.7 cups |
| 60 lb | about 6.9 cups (55 oz) | 11.5 cups |
| 80 lb | about 9.2 cups (74 oz) | 15.3 cups |
| 100 lb | about 11.5 cups (92 oz) | 19.2 cups |
How to measure how much your dog drinks
- Fill the bowl with a measured amount in the morning and note it.
- Top up only with measured amounts during the day.
- Next morning, measure what is left and subtract. Repeat for 2 or 3 days and average.
When drinking is a warning sign
Drinking much more than usual (vets call it polydipsia, over 100 mL per kg a day) can be an early sign of diabetes, kidney disease, Cushing's disease, a uterine infection in unspayed females, or a side effect of medicines like steroids. Drinking very little can lead to dehydration: check the gums (they should be moist) and gently lift the skin on the neck (it should spring back right away). Call your vet about either change.
Planning meals too? The dog food calculator works out daily calories and cups of food.
Sources: Merck Veterinary Manual (normal water intake 50-60 mL/kg/day; polydipsia above 100 mL/kg/day).
Frequently asked questions
How much water should a dog drink a day?
About 1 ounce per pound of body weight, or 50 to 60 mL per kg. A 20 lb dog needs about 2.3 cups and a 60 lb dog about 7 cups a day.
How much water is too much for a dog?
More than about 100 mL per kg a day, which is roughly 1.5 ounces per pound. Steady drinking at that level is a reason to see a vet.
Why is my dog drinking so much water?
Heat, exercise and salty food can all make a dog thirsty. If it goes on for more than a day or two, the common medical causes are diabetes, kidney disease, Cushing's disease and infections, so see your vet.
How long can a dog go without water?
Dogs should never go without water for long. After about 24 hours without water, dehydration becomes dangerous. Always leave fresh water out.
Do dogs on wet food need less water?
Yes. Wet food is about 75% water, so a dog on wet food drinks less from the bowl but gets a similar total amount.
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Last updated October 2026.