Why Is My Dog Drinking So Much Water?

Call your vet now if

• Your dog is drinking much more than usual and is also vomiting or has diarrhoea.
• They are lethargic, weak, or not themselves.
• They are an entire (unspayed) female who is drinking more and seems off-colour, especially in the weeks after a season, or has a discharge from the vulva. A womb infection is one possible reason, and it needs prompt veterinary attention.
• They are drinking a lot and not eating, or losing weight quickly.
• You think they may have eaten something salty in large amounts or anything poisonous (see our toxic foods list).
• They are diabetic and their thirst has changed.
• They seem confused, wobbly, or are breathing heavily at rest.

If any of these apply, please ring your vet, or an out-of-hours emergency vet if your practice is closed.

Normal reasons for drinking more

Thirst naturally goes up and down. Some everyday reasons a healthy dog may drink more include:

• Warm weather. Dogs cool down mainly by panting, which uses water. See our hot weather safety guide.
• Exercise and play. A long walk or a busy day calls for a refill.
• Dry food. Dogs on mainly dry food tend to drink more than those on wet food, because they get less water from their meals.
• Salty treats or chews. Some treats, and table scraps, can make a dog thirsty.
• A change of food. Moving from wet to dry, or to a different recipe, can change how much they drink.
• Excitement or stress. Some dogs drink more when unsettled.

In these cases the increase usually has a clear trigger and settles once the trigger passes. Panting a lot can go hand in hand with drinking more, and our article on why dogs pant explains more.

When a lasting increase matters

If your dog is drinking more day after day, and you cannot link it to heat, exercise or diet, it is worth booking a vet check. A sustained increase in thirst can be associated with a number of conditions, including kidney problems, hormonal conditions, diabetes, liver problems, and infections. Some medicines can also make dogs thirstier.

Drinking more does not mean your dog has any one of these. Many causes are manageable, and some turn out to be minor. The point is that a lasting change is a useful signal, and your vet can examine your dog and may suggest blood or urine tests to find out more.

You might notice other changes alongside thirst, such as:

• Weeing more often, or larger amounts.
• Accidents indoors in a dog who is normally clean.
• Asking to go out at night.
• Changes in appetite or weight.

Mention any of these to your vet, as they help build the picture.

How much is normal?

As a rough guide, we use around 40 to 60 ml of water per kilogram of body weight per day for a healthy adult dog. For a 10 kg dog, that is roughly 400 to 600 ml a day. This is a guide, not a rule. Individual dogs vary, and heat, activity and diet all shift the figure.

Our guide to how much water a dog should drink explains this in more detail, and the pet calculators can work out a range for your dog's weight.

If your dog is consistently drinking well above that range without an obvious reason, it is worth talking to your vet.

Measuring your dog's water intake

Guessing from how often you refill the bowl is not very reliable. A simple measurement over a few days gives you, and your vet, much better information.

1. Use one bowl if you can. If you have several bowls or other pets, try to measure your dog's water separately, or note that the figure covers everyone.
2. Measure in. Fill the bowl with a known amount using a measuring jug, and note the time.
3. Measure out. At the same time the next day, pour what is left back into the jug. The difference is roughly what was drunk, give or take a little spillage and evaporation.
4. Repeat for a few days. One day can be misleading. Three or four days give a clearer trend.
5. Note the context. Write down the weather, walks, meals and any treats. Water from puddles, ponds and garden bowls will not be counted, so mention those too.

Logging these daily figures in Petopedia, alongside meals and toilet habits, helps you give your vet a clear picture of what has changed and when. You can sign up to start tracking.

What to do in the meantime

• Always keep fresh water available. Never restrict water to see whether thirst settles. A dog drinking more may genuinely need it, and limiting water can be harmful.
• Watch their toilet habits. Note how often they wee and whether there are accidents.
• Keep an eye on appetite and energy. See my dog won't eat if their appetite has also changed.
• Take your notes to the vet. Your measurements are genuinely useful. If your vet asks for a urine sample, ask them how best to collect and store it.

For a broader checklist of warning signs, read signs your pet needs a vet, and our guide to knowing your pet's normal covers other everyday habits worth tracking.