Like humans, dogs need water to stay hydrated. Some dogs drip water outside of their bowls, and others have half the water on the floor by the time they're done satisfying their thirst.

As you become accustomed to your dog's drinking habits, you may have noticed your dog drinking lots of water. Although there are more common causes of excessive thirst, such as warmer temperatures and exercise, sometimes there may be no visible causes, indicating that your dog could have an underlying health condition or a reaction to external factors.

It's important that you understand the potential causes of your dog drinking lots of water so that you can more accurately assess your dog's well-being and seek veterinary help if needed.

 

Understanding excessive thirst in dogs

It’s completely normal for dogs to drink regularly throughout the day, but when their thirst suddenly increases, or they start draining the water bowl more often than usual, it can be a sign that something deeper is going on. Understanding why dogs drink, how their body regulates thirst, and what counts as “too much” can help you spot changes early and know when it’s time to speak with your vet.

What is polydipsia?

Polydipsia means excessive drinking. It isn’t a diagnosis on its own, but rather a symptom. Dogs with polydipsia drink noticeably more than their usual amount, or they may seem constantly thirsty even when they’ve just had water.

This increase in drinking often goes hand in hand with increased urination, as the body tries to process the extra fluid.

Polydipsia can be caused by something simple, but it can also be an early sign of a medical condition. That’s why it’s essential to keep an eye on patterns rather than isolated moments of thirst.

 

Normal drinking vs excessive drinking

Every dog is unique, and their water needs depend on their size, activity level, diet, and the temperature. However, most healthy dogs fall into a rough daily guideline.

It's important to note that a single day of extra drinking isn't always a cause for concern, but consistent changes over several days should be monitored.

 

How a dog's body regulates thirst

Your dog's body is constantly balancing water and electrolytes, and several systems work together to control their thirst. The brain monitors your dog's hydration levels, the kidneys filter waste and regulate water balance, and hormones such as antidiuretic hormone (ADH) control how much water the kidneys keep or release.

External factors, such as the temperature and your dog's activity levels, have an effect on their water intake as they influence how much water they lose through panting. This is completely normal however, factors such as stress, medication, illnesses or dehydration can disrupt your dog's internal systems. When that happens, your dog may start drinking more to compensate.

 

How much water should a dog drink?

Knowing how much water your dog should drink makes it much easier to spot when something isn’t quite right. Whilst every dog is different, most healthy dogs drink enough throughout the day to stay hydrated without much encouragement. Sudden changes, such as drinking a lot more or much less, can be an early sign that something needs attention.

Daily water intake guideline and why it varies

There isn't a fixed amount of water that your dog should drink a day, as it can vary depending on different factors. Your dog's size, age, activity level, medication, and weather can all have varying impacts on the amount of water your dog drinks. According to DAVIES, the normal water intake for dogs is around "20-70ml/kg body weight per day." For example, if your dog weighs 20kg, they should consume between 400ml and 1,400ml of water in a day.

Factors that affect how much your dog drinks

As mentioned, there are external factors that can influence your dog's water intake, and it is crucial to keep these in mind if you notice your dog drinking lots of water. For instance, if your dog is highly active on a hot, sunny day, they will naturally need and drink more water to avoid dehydration and heatstroke. Taking note of all these different factors whilst monitoring the amount of water your dog consumes can help you decide whether their water intake is cause for concern.

 

Tracking your dog's water intake

If you’re worried that your dog is drinking more or less than usual, tracking their water intake for a few days can give you a much clearer picture. It doesn’t need to be complicated. A few simple notes can help you decide whether your dog’s thirst is normal or something you should discuss with your vet.

Start by measuring how much water you add to their bowl at the beginning of the day, then check how much is left in the evening. Using the same jug or measuring cup each day helps keep things accurate. If your dog usually has several water bowls, temporarily reduce to one or two so monitoring is easier.

 

Reasons your dog is drinking too much water

Although ensuring your dog is drinking enough water is vital, excessive thirst can indicate something is wrong. Read the list below of potential causes of your dog drinking lots of water:

Diabetes

Diabetes in dogs can cause a dog to consume more water than normal due to imbalanced blood sugar levels. AVMA says, "When the blood glucose reaches a certain level, the glucose overflows into the urine and draws large volumes of water with it."

Diabetes mellitus in dogs is caused by the failure of the pancreas to regulate blood sugar. VCA states that one of "the four main symptoms of diabetes mellitus are increased thirst." Due to insufficient insulin, the glucose (energy source) cannot get to the cells, and the dog's body tries to eliminate the excess glucose by excreting it in the urine. VCA also say, "Since glucose attracts water, it increases the volume of urine produced. To avoid dehydration, the dog drinks more and more water."

Diabetes insipidus is a rare condition in dogs. MSD Veterinary Manual states that diabetes insipidus in dogs is caused by a lack of antidiuretic hormone (ADH) or an inability of the kidneys to respond to ADH. According to VCA, Diabetes insipidus is characterised by excessive thirst and drinking.

 

Cushing's disease

Cushing's disease in dogs, also known as hyperadrenocorticism, occurs when a dog's body produces an excessive amount of cortisol, a steroid hormone that helps regulate various bodily functions.

According to Blue Cross, one of the first symptoms of Cushing's disease that a dog owner will notice is excessive thirst and urination. The excess cortisol interferes with the normal feedback mechanisms that control thirst and fluid balance in the body. As a result, the dog's brain receives signals indicating dehydration, even when the body has enough water.

 

Increased activity or exercise

When your dog exercises, they drink more to stay hydrated and regulate their body temperature. During physical activities, your dog loses fluids through panting and sweating (through their paws). Blue Cross states that dogs "rely on panting and releasing heat through their paw pads and nose to regulate their body temperature".

To compensate for the fluid loss during exercise, your dog instinctively needs to drink more water. Drinking water helps replenish the lost fluids and maintain their body's water balance. Adequate hydration is crucial to prevent overheating and ensure the proper functioning of their organs and muscles during physical exertion.

 

Diet

Your dog's diet can significantly affect the amount of water they drink. The ingredients and whether the food is wet, dry, or raw all have varying effects. Diets that are rich in salt can increase your dog's thirst, therefore leading your dog to drink lots of water.

If your dog is fed a raw, wet or canned dog food diet, you may find and should expect them to drink less water than a dog fed a dry kibble diet. This is because the water content is higher in raw, wet and canned dog food, which contributes to their daily water intake and overall hydration. Simultaneously, dogs fed dry food will need to drink more water to compensate for the lack of moisture in their food.

 

Age

Water is especially important for puppies and their rapidly growing bodies. You may find that a puppy drinks more water as it is a vital part in supporting the growth of their organs, tissues, and muscles. You'd have noticed that puppies are much more active than adult and senior dogs. Their playful demeanour and explorative adventures to discover the new world around them will require them to use more energy and, in turn, drink more water.

Adult dogs generally have stable water needs and are typically only influenced by their activity levels, size, diet, and environmental conditions.

Finally, the metabolism and activity levels of senior dogs tend to decrease, leading to reduced water loss through physical activities. However, as dogs age, they may be more susceptible to health conditions such as kidney problems, which can directly affect their water intake. The results from J Vet Intern Med 2013 report stated that the prevalence of chronic kidney disease in dogs varied widely from 0.05-3.74% in the UK.

 

Climate

As the weather rises in temperature, your dog will drink more water in order to stay hydrated. In hotter weather, your dog's risk of dehydration or, worse, heatstroke significantly rises, and unfortunately, not all dog owners are aware of how serious and easy it is for their dog to become dehydrated very quickly. Dogs do not sweat, and in order for them to cool down, they will pant. Keep a close eye on your dog's behaviour and how much they drink water during warmer days.

On the contrary, you may find that your dog drinks less water during cold weather. But, no matter the temperature outside, always provide your dog with access to fresh, clean water.

 

Certain medications

There are certain medications that can affect your dog's water intake due to their pharmacological effects on their body, so always make sure to read the side effects and discuss them with your veterinarian if you are worried. Some medications may cause a dog to feel thirsty, which is a condition known as polydipsia. This side effect can be a direct result of the medication's impact on the brain's thirst-regulating centres or its effect on certain hormone levels.

Diuretics are commonly prescribed to dogs to manage conditions such as heart failure or kidney problems. According to VCA, the most common side effect of diuretic medication for your dog is increased urination.

Additionally, there are other medications prescribed that may cause side effects like dry mouth or nausea, increasing your dog's thirst. Some medications can affect your dog's metabolism or body temperature regulation, contributing to higher water needs.

It's essential to be vigilant about the effects of various medications and consult with your veterinarian if any concerning changes occur.

 

Kidney disease/chronic renal failure

When the kidneys are not working properly, they lose the ability to concentrate urine. This means your dog may pass larger volumes of diluted urine, which can make them drink more to stay hydrated. According to the MSD Veterinary Manual, reduced urine-concentrating ability (a condition known as isosthenuria) is one of the earliest indicators of renal dysfunction in dogs

In the early stages of kidney disease, increased thirst and urination are often the first changes owners notice at home. As the condition progresses, you may also see weight loss, reduced appetite, vomiting, bad breath, or your dog seeming more tired than usual. VCA Animal Hospitals notes that chronic kidney disease commonly leads to “increased water consumption and urination” long before more severe symptoms appear.

Kidney problems are more common in older dogs, but they can affect dogs of any age. If you notice your dog drinking and peeing more than normal, especially alongside any of the symptoms above, it is important to contact your vet. Early diagnosis is key, and your vet may run urine concentration tests, bloodwork, or imaging to check kidney function.

 

Behavioural & stress causes 

In some cases, dogs drink more due to stress, boredom, habit, or changes in their environment. For example, some dogs may visit the water bowl more often when they are anxious, left alone, feeling unsettled by visitors, or after a big change in routine.

Behavioural or stress-related drinking usually appears alongside other emotional signs, such as pacing, whining, restlessness, or seeking constant reassurance. The dog often seems otherwise healthy, and their appetite and energy levels stay normal.

If you suspect that your dog is drinking a lot of water for behavioural or stress-related reasons, it's still best to rule out any physical or medical causes first with your vet.

 

Other signs and symptoms to look out for

When your dog is drinking more than usual, it’s helpful to watch for other changes in their behaviour or health. These additional symptoms can give you clues about what’s causing their increased thirst and whether it may be linked to an underlying medical issue. Below are some of the most common signs that often appear alongside excessive drinking.

Frequent toilet break (Polyuria)

If your dog is drinking more than usual, you'll often notice they urinate more to compensate. This is known as polyuria. Dogs with polyuria will, of course, ask to go outside more often, and in some cases, may even have accidents inside the home because they can’t hold it for as long as they normally would.

 

Lethargy

Dogs can become lethargic and show little interest in physical activities. When your dog's body is struggling to maintain normal function (for example, due to illness or dehydration), they may seem weak or tired, and lacking their usual energy levels. Your dog needs water to maintain a healthy balance of electrolytes in their body, which is essential for proper muscle function and energy levels. If you notice a significant decrease in your dog's activity and playfulness, you should take them to the vet to get checked, as it can be a symptom of several other health conditions.

 

Loss of appetite

Dogs who are drinking more but eating less may be experiencing nausea, discomfort, or an underlying medical condition. Changes in thirst and appetite often occur together in illnesses such as kidney disease, diabetes, and various gastrointestinal problems. If your dog refuses meals, Dog treats or shows a sudden loss of interest in food overall, it's vital to see your veterinarian.

 

Dry mouth

A dog may exhibit a dry and sticky mouth when they’re ill or dehydrated. You may notice their gums and tongue appearing dry, and their saliva may be thick and rope-like.  Although dry mouth can happen temporarily after exercise or heat exposure, persistent dryness may signal a health issue that needs veterinary attention.

 

Thick, rope-like saliva

When a dog’s hydration levels are out of balance, their saliva can turn thick and sticky instead of thin and watery. This is the body’s way of conserving moisture. If your dog has rope-like saliva alongside increased thirst, it suggests their body is working harder than usual to maintain normal hydration.

 

Vomiting and diarrhoea

Vomiting and diarrhoea can both cause fluid loss, which may lead your dog to drink more to replace what their body has lost. However, these symptoms can also signal infections, dietary issues, or more serious conditions like pancreatitis or kidney disease. If vomiting or diarrhoea accompany increased thirst, especially if these symptoms last longer than 24 hours, it’s crucial to get your dog checked by the vet.

 

Other systemic signs (panting, weakness)

Some dogs show more general or subtle signs of illness when they’re drinking excessively. These may include increased panting, weakness, trembling, or restlessness. Panting helps dogs regulate temperature, but excessive panting without exercise or heat exposure can suggest pain, stress, hormonal disorders, or internal changes such as an electrolyte imbalance.

 

When to see a vet (and what to expect)

If your dog is drinking more than usual for several days in a row, or you’ve spotted other symptoms alongside their increased thirst, it’s best to speak with your vet as soon as possible. Excessive drinking can have a range of causes. Some are simple, and others need early treatment, so it’s always better to get things checked sooner rather than later.

Your dog’s history and physical examination

At the vet check-up, they will begin by asking a series of questions, such as how much water your dog has been drinking, how frequently they’re urinating, their appetite, diet, weight, stress, exercise level, and what medications your dog may be taking.

Your vet will then carry out a physical examination to help create a clearer picture of what may be wrong with your dog. The examination includes checking their body condition, heart rate, temperature, abdomen, hydration levels, and gum colour.

 

Diagnostic tests to find the cause

If further investigation is needed, your vet will most likely recommend diagnostic tests. These often include blood tests to assess your dog’s kidney function, blood sugar levels, liver enzymes, electrolytes, and signs of infection or inflammation.

Urine testing is also a very common test, as it helps show how well the kidneys are concentrating urine and whether substances such as glucose, protein, blood, or bacteria are present. In some cases, urine cultures may be suggested to rule out infection.

Depending on what your vet finds, they may also recommend imaging, such as X-rays or an ultrasound, to look at internal organs more closely or rule out conditions like bladder stones or adrenal gland changes.

 

Treating the underlying condition

Once the cause of your dog’s excessive thirst is identified, treatment will focus on managing that condition. This may involve medication, dietary changes, or a combination of both.

For example, diabetes may require insulin therapy, kidney disease often involves prescription diets and supportive care, and hormonal conditions like Cushing’s disease are managed with long-term medication. Your vet will talk you through the options and what to expect moving forward.

 

Ongoing monitoring and follow-up care

Many conditions linked to increased thirst require ongoing monitoring. Your vet may schedule follow-up appointments to repeat blood or urine tests and check how well treatment is working.

At home, keeping a simple record of your dog’s water intake, toilet habits, appetite, and energy levels can be extremely helpful. These notes allow both you and your vet to spot improvements early or act quickly if something changes.

 

Keep an eye on your dog's water consumption

It's important to pay attention to the amount of water your dog drinks on a daily basis to make it easier to spot if your dog is drinking too much or too little water.

Whilst it's important to ensure your dog stays hydrated, drinking too much water can be a sign that something is wrong. By keeping an eye on your dog's behaviour and water consumption, you can help ensure that they stay healthy and happy. If you notice any changes in their drinking habits, consult your veterinarian to rule out any underlying health issues. Remember, prevention and early detection are key when it comes to your dog's health. Additionally, ensure you have good pet insurance, as you never know when a minor or major problem could occur with your beloved four-legged friend.