How much water should a dog drink a day?
A widely used rule of thumb is about 1 fluid ounce of water per pound of body weight a day, as Whole Dog Journal’s vet-written guide explains. So a 40 lb dog drinks roughly 40 fl oz, or 5 cups. In metric that works out to roughly 65 ml per kg.
That’s a guide, not a target to hit exactly. Plenty of healthy dogs drink a fair bit more or less depending on the day.
When is it too much?
Vets generally treat more than 100 ml per kg of body weight a day as excessive drinking, called polydipsia. For a 40 lb dog that’s about 1.8 liters, or 61 fl oz. If your dog is regularly drinking above that line, especially if it’s also peeing more or having accidents, book a vet visit. Increased thirst can be an early sign of:
- Kidney disease
- Diabetes
- Cushing’s disease (an overactive adrenal gland)
- Pyometra, a womb infection in unspayed females that needs urgent care
- Side effects of some medicines, such as steroids
Dog water intake chart
| Dog weight | Typical a day | Typical (metric) | Worth a vet check above |
|---|---|---|---|
| 10 lb (5 kg) | 10 fl oz (1.25 cups) | 0.3 L | 15 fl oz (0.5 L) |
| 20 lb (9 kg) | 20 fl oz (2.5 cups) | 0.6 L | 31 fl oz (0.9 L) |
| 30 lb (14 kg) | 30 fl oz (3.75 cups) | 0.9 L | 46 fl oz (1.4 L) |
| 40 lb (18 kg) | 40 fl oz (5 cups) | 1.2 L | 61 fl oz (1.8 L) |
| 50 lb (23 kg) | 50 fl oz (6.25 cups) | 1.5 L | 77 fl oz (2.3 L) |
| 60 lb (27 kg) | 60 fl oz (7.5 cups) | 1.8 L | 92 fl oz (2.7 L) |
| 80 lb (36 kg) | 80 fl oz (10 cups) | 2.4 L | 123 fl oz (3.6 L) |
| 100 lb (45 kg) | 100 fl oz (12.5 cups) | 3.0 L | 153 fl oz (4.5 L) |
Things that change how much a dog drinks
- Food. Dogs on wet food get a lot of water from meals and drink less from the bowl. Dogs on dry kibble drink more.
- Heat and exercise. Hot days and long walks can raise water needs a lot. Always carry water on outings.
- Age and size. Puppies and nursing mothers often need more.
- Salty snacks. Treats and chews high in salt make dogs thirstier.
How to measure: fill the bowl with a measured amount in the morning, top up with measured amounts through the day, and measure what’s left the next morning. Do it for two or three days and take the average. If you have more than one pet, this only works if they don’t share the bowl.
Signs a dog isn’t drinking enough
Dry, sticky gums, sunken eyes, tiredness and skin that stays “tented” when gently pinched over the shoulders can all point to dehydration. A dog that won’t drink for a day, or that’s vomiting or has diarrhea, should see a vet.
Common questions
How much water should a 50 lb dog drink?
About 50 fl oz, or a little over 6 cups, a day. Drinking regularly over about 2.3 liters (77 fl oz) is worth a vet check.
Should I limit my dog’s water?
No, not unless your vet tells you to. Healthy dogs should always have fresh water available.
Why is my dog suddenly drinking so much?
Heat, exercise or a change to dry food can explain it. If none of those apply, or it lasts more than a day or two, see your vet.
Do puppies need more water?
Puppies often drink more for their size and need frequent access, especially when active.
How much should my dog eat?
Use our dog food calculator for daily portions.
Sources
Last reviewed .