How much water should a dog drink a day?

A healthy adult dog drinks about 40–60 ml of water per kilogram of body weight a day (American Kennel Club), roughly one US fluid ounce per pound. For a 10 kg dog that is 400–600 ml; for a 30 kg dog, 1.2–1.8 litres. The MSD Veterinary Manual gives a similar figure for mammals in general, about 44–66 ml per kg in a comfortable temperature. Weather, exercise and food change the number a lot, so the amount that matters most is your own dog's usual intake, and whether it has changed.

How much water a dog needs

These are estimates, not targets. The AKC and the MSD Veterinary Manual agree on the practical rule: give your dog constant access to fresh water, and a healthy dog will take what it needs. Don't restrict water unless your vet has told you to.

5 kg200–300 ml

10 kg400–600 ml

20 kg800–1200 ml

30 kg1200–1800 ml

40 kg1600–2400 ml

00.6 l1.2 l1.8 l2.4 l

Body weight	Water per day (ml)
5 kg	200–300 ml
10 kg	400–600 ml
20 kg	800–1200 ml
30 kg	1200–1800 ml
40 kg	1600–2400 ml

Computed from the American Kennel Club's 40–60 ml per kg a day, as in the table above. A dog on wet food drinks less from the bowl.

Puppies

Puppies need more water for their size than adult dogs, because they are growing, and they are more prone to dehydration (American Kennel Club). The AKC's figures:

• Puppies that are starting to wean need about half a cup of water every two hours.
• Weaned puppies need about half an ounce to one ounce per pound of body weight a day. A 20 lb (9 kg) puppy drinks about 10–20 oz (300–600 ml), and more on an active day.
• During house training, the AKC suggests taking the bowl up about two to three hours before bedtime, and never restricting water during the day.

Our puppy feeding schedule places meals through the day; a drink usually follows each one.

What changes how much a dog drinks

• Food. The MSD Veterinary Manual puts the water content of canned food at roughly 60% to over 87%, and of dry food at 3–11%. Dogs on mostly wet food drink much less from the bowl, which is normal.
• Heat and exercise. Dogs cool down by panting, which loses water, so hot days and long walks mean a bigger drink (American Kennel Club).
• Illness. Vomiting, diarrhoea and fever all raise water needs, and the AKC warns they can lead to dehydration quickly.
• Swimming and play. A dog that swallows water while swimming or playing with a hose drinks less afterwards, and in rare cases too much.

Signs of dehydration

The AKC lists these signs: reduced skin elasticity, loss of appetite, vomiting with or without diarrhoea, low energy, panting, sunken or dry-looking eyes, a dry nose, dry or sticky gums, and thick saliva. Two checks you can do at home:

1. Skin tent. Gently lift the skin between the shoulder blades and let go. In a well-hydrated dog it springs straight back; in a dehydrated dog it settles slowly. Try it when your dog is well so you know its normal, because wrinkly breeds have looser skin anyway.
2. Gums. Touch the gums: they should be moist, not sticky. Press a spot gently and release; the pink should return almost immediately. The AKC notes that in a dehydrated dog the refill can take up to three seconds or more.

A dog that shows these signs and isn't drinking, or is vomiting, needs a vet the same day.

Drinking too much

Drinking much more than usual can be the earliest sign of illness. The AKC puts the medical threshold for polydipsia at more than 100 ml per kg of body weight a day, and adds that a clear rise above your own dog's baseline matters even below that. Common causes are diabetes, Cushing's disease and chronic kidney disease, and each usually starts with your dog peeing more. The PDSA lists the same conditions, plus urine infections, pyometra in unspayed females, liver disease and some medicines such as steroids.

Watch for: the bowl needing refills far more often, drinking from puddles or the toilet, asking to go out more, longer wees, and new accidents indoors. The PDSA's advice is simple: always contact your vet if you think your dog is drinking or peeing more than normal, and never restrict water to control it.

How to measure your dog's intake at home

Both the AKC and the PDSA want one number from you: how much your dog drinks in 24 hours.

1. Fill the bowl from a measuring jug and note the amount.
2. Top up from the jug through the day, noting each top-up.
3. After 24 hours, measure what is left and subtract. The total is your dog's daily intake.

Divide by your dog's weight in kilograms to compare with the 40–60 ml per kg range. Do it for three or four days, because one hot day or a long walk can skew a single reading. If you have more than one dog, you will need separate bowls in separate rooms for the test. Write the readings down with the date; a change over weeks is easier to see on paper, or in a log, than from memory.