Health
The bowl filled three times a day, requests to go out at two in the morning, a puddle in the hall. Sometimes it is just summer. Sometimes it is the first sign of illness.
Caution. An unspayed bitch drinking a lot a few weeks after her season, or any dog drinking a lot who vomits, will not eat, lies flat, loses weight fast or passes very little urine: ring your own vet today. Do not cut his water in the meantime.
Do not look for the answer in a Facebook group, on TikTok or on a forum. Look for someone trained for this: your dog's own veterinarian, the only person who can examine, investigate and treat them.
Use this page to know what to observe, what to note and what to ask at the appointment, not to treat at home. If you still have doubts after a consultation, ask another vet or a specialist (dermatologist, internist) for a second opinion, not a group. And if you do not have a regular vet yet, find one now, while your dog is healthy: how to choose a veterinary clinic.
You noticed it at the bowl. One fill a day used to do; now it is three. The dog wants out at two in the morning, and in the hall you have found a puddle the size of a dinner plate, from a dog who has not had an accident indoors in years. Or it is a different story: it is August, he has run for an hour in the park and he is drinking as if he had not seen water for a week. The first dog needs a vet. The second needs shade and a full bowl. This page helps you tell them apart: how to measure, which signs mean a phone call today, what the vet will be looking for, and why you do not cut his water, however tiresome the puddles get.
Thirst usually builds slowly, over weeks, and you only notice when the bowl is always empty. A few combinations should not wait for a routine appointment:
For every other dog who has been drinking noticeably more for a few days with no reason in sight (a heatwave, hard exercise, a new bag of dry food), book an appointment this week and bring a urine sample. It is not a middle-of-the-night emergency. Leaving it until next month is not an option either.
"He drinks a lot" tells the vet nothing. "He drinks 2.4 litres a day, and has done for three days" tells them nearly everything. You collect the numbers, and it is not hard.
A healthy dog drinks around 50 to 60 ml per kilogram a day, a bit more in summer and after a run. Over 100 ml per kilogram a day, vets already consider too much. For a 10 kg dog that threshold is a litre a day. A 20 kg dog drinking 2.5 litres three days running, at 20 degrees and without any hard exercise, is drinking too much, whatever the neighbours tell you.
The vet will almost certainly ask for one, so bring it with you. The best is the first of the morning, caught mid-stream in a clean container (a well-washed food tub does the job, then pour it into a sample pot from the pharmacy). Keep it cool and get it to the clinic within two or three hours. The morning urine is the most concentrated of the whole day, so it tells the vet the most.
The gundog after two hours in stubble. The bitch feeding a litter. The dog switched this week from tins to kibble. The dog who stole a slice of salami. They all drink more, and so they should. At our summer training sessions the dogs drink after every trail, and we carry water in the car for each of them. This kind of thirst has a reason you can see with your own eyes, and it settles within a day or two, along with the reason. The thirst of illness has no reason you can point at, and it does not settle.
| What you see alongside the thirst | What the vet is thinking of |
|---|---|
| Only in summer, after exercise or after dry food | Normal, it settles on its own |
| Eats a lot, loses weight, urinates a lot | Diabetes |
| Older dog, pale urine, sometimes vomiting, weight loss | Kidney disease |
| Sagging belly, thin coat, panting, eats greedily | Cushing's (his body makes too much cortisol) |
| Unspayed bitch, 4 to 8 weeks after her season | Womb infection (pyometra), an emergency |
| Urinates often, small amounts, with discomfort | Urinary infection |
| Has started a new treatment | Side effect of a medicine |
| Yellowish gums, vomiting, listlessness | Liver disease |
The table does not diagnose and does not get you out of the trip. Several illnesses give exactly the same thirst, and in an old dog two of them can run side by side.
It does happen that, after all the tests, nothing turns up: the dog drinks a lot out of boredom or habit. That conclusion is only acceptable at the end, once illness has been ruled out. No decent vet accepts it at the start, and rightly so.
Keep the bowl full and clean and within reach, and go to the appointment with the numbers in your phone. A dog who drinks a lot and gets to the vet early has, with most of the illnesses in the table, good years ahead of him.
What dog owners search for most often on the internet about this problem, with the short answer. The answers are a guide only: the decision belongs to your dog's own vet, after an examination.
Around 50 to 60 ml per kilogram a day, more in summer, after a run or on a dry-food-only diet. Over 100 ml per kilogram a day is too much in any vet's eyes: for a 10 kg dog, more than a litre. Before you draw a conclusion, measure for three days running, everything you put in and everything left in the bowl.
Sometimes for ordinary reasons: a heatwave, exercise, dry or salty food, a medicine started recently. When it lasts and has no explanation, the commonest causes are diabetes, kidney disease, Cushing's (too much cortisol), urinary infections and, in unspayed bitches, infection of the womb. A urine test and blood tests tell them apart.
It is not something to put off. In older dogs, new thirst is often the first sign of kidney disease, diabetes or Cushing's, all easier to keep in check when caught early. Book an appointment the same week and bring the litres you measured at home and a morning urine sample.
No. If he drinks a lot because of his kidneys or diabetes, his body needs that water, and restricting it can dehydrate him within hours. Let him out more often, put a pad down at night and see the vet. Once the cause is treated, the thirst usually drops by itself.
Usually a urine test (how concentrated it is, whether it contains sugar, protein or bacteria) and blood tests: a blood count and biochemistry, with blood sugar, kidney and liver values and calcium. After the first results, tests for Cushing's or diabetes and an abdominal ultrasound may follow. The vet picks the order from what they find at the examination.
The information on this page is educational and does not replace an examination. For full details and a diagnosis, consult your dog's own veterinarian.
They often come together: the same causes, plans that complement each other.
The water bowl is empty by lunchtime, she wakes you at night to go out and loses weight though she eats everything. Diabetes is for life, but very manageable.
He drinks more, wees more and slowly loses weight. Chronic kidney disease shows late, acute failure is an emergency measured in hours. Tests reveal both.
She is drinking for two, licking under her tail and finished her season a few weeks ago. Pyometra is an emergency, even when you can see no discharge at all.
He asks to go out every hour, squats and passes a little, sometimes pink. Cystitis is the obvious guess, but stones and the prostate look the same at first.
We work with your dog's behaviour, not its health. For any sign described here, book an appointment with your own vet; the related services page explains how to choose a clinic.