How much water should a cat drink per day? The commonly cited veterinary range is about 40 to 60 ml of water per kg of body weight per day — so a 10 kg cat needs about 400 to 600 ml a day, and a 30 kg cat needs about 1.2 to 1.8 litres. That range is a starting point, not a prescription: a cat that eats wet food takes in a lot of water with its food and drinks less from the bowl, a cat that eats dry food drinks more, and hot weather, exercise, illness, and nursing all push the amount up. This guide gives the water table by weight, explains what changes the amount, and covers the signs of dehydration and the signs that drinking too much needs a vet.
The short version is: always have fresh water available, in more than one place, and let the cat drink when it is thirsty — a healthy cat is good at regulating its own water intake, and the owner's job is to make water available, not to measure every sip. Measure the amount only if you are worried: fill the bowl to a known level in the morning, measure what is left in the evening, and repeat for a few days. If the cat is drinking much more or much less than the range in the table below, or if its drinking has changed suddenly, mention it to your vet — a sudden change in drinking is often the first sign of illness. The dog water intake calculator works out the figure for any weight, and the cat feeding chart by weight guide gives the food amounts that go with it.
How much water should a cat drink per day?
The range vets commonly cite is about 40 to 60 ml per kg of body weight per day. That is the total water the animal takes in, from the bowl and from its food together. A wet food is about 70 to 80% water, so a pet that eats wet food may drink very little from the bowl and still be well hydrated — while a pet that eats dry food, which is only about 10% water, must drink almost all of its water from the bowl. That is why the bowl matters more for a pet on dry food, and why a pet that switches from wet to dry food will suddenly seem to drink a lot more: it is not drinking too much, it is making up for the water that used to come in its food.
| Body weight | Water per day (about) | In litres |
|---|---|---|
| 2 kg | 80–120 ml | About 0.1 litres |
| 3 kg | 120–180 ml | About 0.15 litres |
| 4 kg | 160–240 ml | About 0.2 litres |
| 5 kg | 200–300 ml | About 0.25 litres |
| 6 kg | 240–360 ml | About 0.3 litres |
| 7 kg | 280–420 ml | About 0.35 litres |
If your cat is between two rows, take the middle of the range for its weight. Note that the table is for a healthy adult cat at rest in normal weather — a cat that has been exercising, that is in hot weather, that is nursing, or that is ill will need more, and a cat that eats wet food will drink less from the bowl. The right amount is the one that keeps the cat hydrated: moist gums, skin that springs back when gently pinched, and normal energy. The how much food should a kitten eat guide gives the food tables for young cats, and the senior cat diet guide covers water for older cats.
What changes how much a cat drinks?
Food is the biggest factor: a cat on wet food drinks much less from the bowl than a cat on dry food, because wet food is mostly water. Weather is the next: a cat in hot weather, or after exercise, drinks more — sometimes much more — and that is normal, as long as it settles back to normal when the weather cools or the exercise ends. Activity matters too: a working or very active cat loses water through panting and exercise, and needs more to replace it. Age matters: a kitten drinks more per kg than an adult because it is growing, and a senior cat may drink more because its kidneys concentrate urine less well — which is normal in old age, but a sudden increase in an older cat is worth mentioning to your vet.
Illness is the factor that matters most. A cat that suddenly starts drinking much more than usual, or much less, may be ill — increased thirst is a common early sign of diabetes, kidney disease, and some other conditions, and a cat that stops drinking is at risk of dehydration within a day. Medication can change drinking too: some medicines make a cat drink more, and your vet should tell you if that is expected. If your cat's drinking has changed suddenly, measure it for a few days and take the numbers to your vet — a measured change is far more useful than a feeling that it seems to drink more. The diabetes in cats guide and the kidney disease in cats guide explain the conditions where thirst changes first.
Signs of dehydration in cats
A dehydrated cat has dry or sticky gums, skin that stays tented when gently pinched and released, sunken eyes, and lethargy — and in a bad case, a fast heartbeat and cold paws. The skin test is the easiest to do at home: gently pinch the skin on the back of the neck or between the shoulder blades, let go, and watch how fast it springs back. In a well-hydrated cat it springs back at once; in a dehydrated cat it stays tented for a second or two. The test is less reliable in very old or very thin cats, whose skin is less elastic anyway, so use it with the gums and the general state of the cat, not on its own.
If a cat is mildly dehydrated after a hot day or a bout of vomiting or diarrhoea, offer small amounts of fresh water often, and call your vet if it will not drink, if it vomits the water back up, or if it is lethargic. Do not force water into a cat's mouth — it can go down the wrong way. A cat that is badly dehydrated needs a vet, not a bowl: it may need fluids under the skin or into a vein, and the cause of the dehydration needs finding. Young cats dehydrate faster than adults, so a kitten with vomiting or diarrhoea should be seen by a vet the same day. The table above is the reference — the related guides below cover food, age, and health.
How to encourage a cat to drink more
Put fresh water in more than one place, in clean bowls, away from the food bowl and away from the litter tray — many cats, and cats in particular, prefer to drink away from where they eat. Change the water daily, wash the bowls daily, and use a wide, shallow bowl for cats, whose whiskers can touch the sides of a narrow bowl and put them off drinking. Some cats drink more from a running tap or a pet fountain, because moving water attracts them — a fountain is worth trying for a cat that does not drink enough. Adding a little water to dry food, or offering wet food, also increases water intake without the cat having to drink more from the bowl.
Do not add flavourings, milk, or broth to the water without veterinary advice: milk upsets many adult cats, and broth is often salty, which makes thirst worse rather than better. Do not restrict water to stop a cat urinating in the house — a cat that needs water and cannot get it will dehydrate, and a cat that is urinating in the house needs a vet, not less water. If your cat drinks a lot more than the table suggests and it is not hot, not exercising, and not eating dry food, measure the amount for a few days and take it to your vet: increased thirst is a common early sign of illness, and it is better to check it early than to wait.
When drinking too much needs a vet
See a vet if your cat is drinking much more than the range in the table for more than a few days, if its drinking has increased suddenly, if it is urinating much more or having accidents in the house, or if it is drinking a lot and losing weight at the same time. Those are common early signs of diabetes, kidney disease, and some other conditions, and they are all easier to treat when they are caught early. Bring a measured amount — fill the bowl to a known level in the morning, measure what is left in the evening, and repeat for three days — because a measured number helps the vet far more than a feeling that the cat drinks a lot.
See a vet the same day if a cat will not drink at all, if it vomits water back up, if it is lethargic or collapsed, or if a kitten has vomiting or diarrhoea. A cat that is not drinking can dehydrate within a day, and a kitten faster than that. At the vet, expect a physical check, and possibly a blood test and a urine test — those are the usual first steps when drinking has changed, and they show whether the kidneys, the blood sugar, and the hydration are normal. The cat calorie calculator works out daily food for any weight, and the adult cat food calculator guide gives the full food tables.
For related reading, see the cat feeding chart by weight guide, the cat feeding chart by weight guide, the diabetes in cats guide, the kidney disease in cats guide, the cat calorie calculator, the senior cat diet guide.
Frequently asked questions
How much water should a cat drink per day?
The commonly cited veterinary range is about 40 to 60 ml per kg of body weight per day — so a 10 kg cat needs about 400 to 600 ml a day, and a 30 kg cat needs about 1.2 to 1.8 litres. A cat on wet food drinks less from the bowl, because wet food is mostly water, and a cat in hot weather or after exercise drinks more. Always have fresh water available in more than one place.
How do I know if my cat is dehydrated?
Check the gums — they should be moist, not dry or sticky — and the skin test: gently pinch the skin on the back of the neck, let go, and watch how fast it springs back. In a well-hydrated cat it springs back at once; in a dehydrated cat it stays tented for a second or two. A dehydrated cat is also lethargic, with sunken eyes. If a cat will not drink, or vomits water back up, see a vet the same day.
Why is my cat drinking more than usual?
Hot weather, exercise, dry food, and nursing all increase drinking, and that is normal. But a sudden increase that lasts more than a few days, especially with more urination or weight loss, can be an early sign of diabetes, kidney disease, or another condition. Measure the amount for three days and take the numbers to your vet.
Should a cat on wet food drink less water?
Yes — wet food is about 70 to 80% water, so a cat on wet food may drink very little from the bowl and still be well hydrated. A cat on dry food, which is only about 10% water, must drink almost all of its water from the bowl. That is why a cat that switches from wet to dry food suddenly seems to drink a lot more.
How can I get my cat to drink more water?
Put fresh water in more than one place, in clean bowls, away from the food bowl, and change it daily. Use a wide, shallow bowl for cats, and try a pet fountain — many cats drink more from moving water. Adding a little water to dry food, or offering wet food, also increases water intake. Do not add milk or salty broth to the water.
Is it normal for a senior cat to drink more?
Older cats often drink a little more, because their kidneys concentrate urine less well — which is normal in old age. But a sudden increase in an older cat is worth mentioning to your vet, because increased thirst is a common early sign of kidney disease and diabetes, and both are easier to treat when they are caught early.
Results on this page are estimates for general information only and are not veterinary advice. If your pet is ill, underweight, overweight, pregnant, or has a health condition, consult your veterinarian before changing diet or care.