If your dog suddenly starts finishing the whole water bowl when they never used to, I would pay attention. A clear change from your dog’s normal drinking pattern matters more than whether they drink more than another dog.
There may be a simple explanation, such as hotter weather, more exercise or a change from wet food to dry food. But genuine increased thirst can also be one of the earliest signs of an underlying medical problem. This is particularly important in older dogs, where kidney disease, diabetes and hormonal disease such as Cushing’s may first appear as increased drinking and urination.
Do not restrict access to water. Instead, notice whether your dog is also urinating more, losing weight, eating differently or seeming unwell, and arrange an examination if the change persists or concerns you.
First, confirm what has changed
When an owner tells me their dog is drinking more, I first want to understand what has changed.
I usually ask:
- Is your dog drinking more than they normally do?
- Have you recently started adding water to their food?
- Has their diet changed?
- Are they eating more dry kibble or biscuits?
- Has the weather been particularly hot?
- Have they been exercising more?
- Are they also urinating more?
- Have they lost weight?
Diet can make quite a difference. A dog eating wet or fresh food already gets a significant amount of water through meals, whereas a dog eating dry kibble generally needs to drink more separately.
That is why I am usually more interested in a clear change from that dog's normal drinking pattern than in whether they simply seem to drink more than another dog.
How much water should a dog normally drink?
As a practical guide, I generally expect a dog to drink around 40–60 mL of water per kilogram of body weight each day.
For example, a 10 kg dog may drink roughly 400–600 mL a day.
That is only a rough guide. Water intake varies with:
- weather
- exercise
- diet
- how much moisture is already in the food
- salt content of the diet
- some medications and prescription diets
So I would not diagnose a problem from an exact number alone.
If your dog's normal pattern has clearly changed, that matters more to me.
Notice how often and how much your dog urinates
Drinking and urinating usually need to be considered together.
Many younger healthy dogs may urinate around two to four times a day. Older dogs often go more frequently.
I also ask owners to notice how much urine is being produced.
There is a difference between a dog producing several large puddles and a dog repeatedly trying to pass tiny amounts. Frequent small amounts can suggest a lower urinary problem such as bladder irritation or infection, whereas passing much larger volumes fits better with true increased urine production.
What can cause a dog to drink more water?
There are many possible causes, and the dog's age makes a difference.
In a younger dog who is otherwise completely well, I am often less concerned initially. Sometimes there is an obvious explanation such as hotter weather, increased exercise or a dietary change.
Medical causes can still occur, including urinary tract disease, diabetes and hormonal disorders.
In older dogs, I become more interested in underlying disease because several common senior conditions can first appear as increased thirst.
Kidney disease
One of the subtle early changes owners may notice with kidney disease is that their dog starts drinking and urinating more.
Chronic kidney disease becomes increasingly important as dogs age, and increased thirst and urination are recognised warning signs.
Read more: Chronic Kidney Disease in Dogs
Diabetes
Diabetes is another important cause.
When blood glucose becomes high enough, glucose spills into the urine. Water follows it, so the dog urinates more and then drinks more to replace that fluid.
Weight loss despite a reasonable or increased appetite can occur as well.
One thing I see occasionally is an owner mentioning that their dog has been emptying the entire water bowl for several weeks, only for us to discover that the dog is diabetic.
That is why I do not consider a major change in thirst something to ignore just because the dog still appears relatively well.
Cushing’s disease
Cushing’s disease is another condition I think about particularly in middle-aged and older dogs.
Increased drinking and urination are common signs. Dogs may also develop increased appetite, panting, muscle weakness, a pot-bellied appearance or skin and coat changes.
Urinary problems
Urinary tract disease can also change toileting behaviour.
Sometimes an owner initially describes this as “drinking and peeing more”, but when we look more closely, the dog is actually trying to urinate repeatedly and only passing small amounts.
That distinction is useful because it can point us in a different diagnostic direction.
Why I pay particular attention in senior dogs
In an older dog, a noticeable increase in thirst is something I would take seriously even if everything else seems fairly normal.
Kidney insufficiency, diabetes and Cushing’s can all begin with fairly subtle changes at home. Increased thirst and urination may appear before an owner sees more obvious signs of illness.
This is one reason I ask about drinking and toileting habits during senior health checks.
If an older dog has started drinking noticeably more than usual, I would rather investigate it early than wait until they are clearly unwell.
Read more: Senior Dog Care: A Veterinarian’s Guide to Helping Your Dog Age Well
What I usually check first
I start with the history and a physical examination.
Then one of the most useful first tests is usually a urine test.
I look at the urine specific gravity, which tells me how concentrated or dilute the urine is. I also look for things such as:
- glucose
- protein
- blood
- white blood cells
- crystals
- bacteria
If the urine is dilute or the history strongly suggests genuine increased thirst and urination, I will usually investigate further with blood tests.
What we do after that depends on the dog's age, examination findings and results.
Read more: Understanding Dog Blood Work · Longevity Blood Tests for Dogs
When is increased drinking urgent?
Drinking more water by itself is not always an emergency, but I would seek veterinary attention promptly if your dog is also:
- not eating
- very lethargic or clearly not themselves
- vomiting repeatedly
- weak or collapsing
- not toileting normally
- trying to urinate but unable to pass urine
- drinking heavily but producing very little or no urine
A dog that cannot urinate normally needs urgent assessment.
More generally, when increased thirst appears alongside a dog who is clearly unwell, I would not wait for a routine appointment.
Read more: Dog Not Eating? When to Worry and What to Do
What can you do at home?
If you have noticed a change, start paying attention to the pattern.
If practical, measure how much water you put into the bowl over 24 hours and how much is left at the end. If you have several pets sharing the same bowl, this may obviously be difficult.
Also note:
- how often your dog urinates
- whether the urine puddles are much larger than before
- any accidents in the house
- appetite changes
- weight loss
- vomiting or diarrhoea
- recent diet changes
- medication or supplement changes
Most importantly, do not restrict your dog's access to water just because they are drinking a lot. Increased thirst may be the body's attempt to compensate for excessive fluid loss.
If your senior dog is due for a health check and you have noticed increased drinking, mention it to your veterinarian. If your clinic is happy for you to do so, bringing a fresh urine sample can also be useful.
The main thing I want owners to notice
A dog drinking more than another dog does not automatically mean there is a problem.
What matters much more is a change from your own dog's usual pattern.
If your dog has suddenly started finishing the water bowl, asking to go outside more often or producing much larger volumes of urine, I would not simply put it down to age.
In an older dog especially, that small change may be one of the earliest clues that something needs looking into.
References
- American Animal Hospital Association. Diabetes in Dogs and Cats: Symptoms, Diagnosis, and Treatment.
- American Animal Hospital Association. 2026 AAHA Diabetes Management Guidelines for Dogs.
- American Animal Hospital Association. 2023 AAHA Senior Care Guidelines for Dogs and Cats.
- American Animal Hospital Association. 2023 Selected Endocrinopathies Guidelines: Canine Hypercortisolism.
- MSD Veterinary Manual. Disorders of the Pituitary Gland in Dogs.
- MSD Veterinary Manual. Diabetes Mellitus in Dogs and Cats.
This article is for educational purposes only and does not replace professional veterinary advice. If your dog is unwell, please consult your veterinarian.