Why is my cat drinking so much water?

Key Takeaways:

- Cats may drink more due to simple factors like heat, diet changes, or increased activity.

- Persistent excessive thirst can be linked to medical conditions such as kidney disease or diabetes.

- If increased drinking is paired with other symptoms, it’s important to consult a vet promptly.

If you’ve noticed your cat suddenly guzzling much more water than usual, it’s completely natural to feel concerned - especially when cats are often known for turning their noses up at the water bowl. While increased thirst is often harmless, it should never be ignored.

Sometimes your cat might just be thirstier because of everyday factors like warmer weather, dietary changes, or increased activity. However, drinking more than usual can also be a sign of an underlying health condition.

Here we’ll explore both serious and non-serious causes of excessive drinking in cats, including in kittens and older cats, the signs to watch for, and when it’s time to seek veterinary advice.

Why is my cat drinking more than normal?

Every breed & need is different, so there’s no golden rule for how much a cat should be drinking each day. 

The general advice is 40-60 ml of water per kilogram of their body weight - but this can vary widely depending on genetics, as well as your cat’s individual diet (wet foods usually have a much higher water content than dry kibble). 

It can also be difficult to keep track of how much your cat’s drinking because their intake isn't limited to their water bowl.

Lots of cats drink from fountains, leaking taps, and abandoned glasses of water (we can’t be the only ones who have learned that the hard way). 

Meaning counting their water to the millilitre is usually a losing battle. We recommend looking for changes in their drinking behaviour instead, rather than tracking their intake. 

For example, if they’re visiting their water bowl noticeably more than usual, or you’re seeing lots more clumps in their litter box all of a sudden, it’s time to pay more attention to their water intake.

Causes that require a vet visit

If your cat’s increased drinking is persistent or comes with other unusual symptoms, it could be a sign of an underlying health problem. 

Trust your instincts. Getting your cat checked by a vet quickly is important, as early diagnosis can make a big difference in treatment outcomes.

Common underlying causes of increased thirst (medically known as ‘polydipsia’) include:

Kidney disease

Particularly common in older cats, kidney issues affect the body’s ability to retain water, making your cat drink more water.

Other symptoms to watch for: 

• Increased urination

• Lethargy or decreased activity

• Weight loss

• Poor coat condition

• Vomiting or nausea

Diabetes

Excessive drinking is one of the main symptoms of diabetes. It can affect any cat, but overweight cats and certain breeds, such as Burmese, are at a higher risk.

Other symptoms to watch for:

• Sudden weight loss despite eating normally or more than usual

• Increased appetite

• Lethargy

• Occasional vomiting or diarrhoea

Hyperthyroidism

This condition speeds up their metabolism, causing them to drink more. Older cats are more commonly affected, especially Siamese or domestic shorthairs - but no matter the age or breed, if your cat shows any of these symptoms, it’s important that they’re checked by a vet as soon as possible. Symptoms to look out for:

• Weight loss despite a healthy or increased appetite

• Hyperactivity or restlessness

• Rapid heartbeat or panting

• Poor coat quality

• Being more vocal

Urinary tract issues

UTIs can cause your cat to drink more water and urinate more frequently. They’re most common in kittens and senior cats, or those with underlying medical issues such as bladder stones.

Other symptoms to watch for:

• Frequent trips to the litter box or straining to urinate

• Blood in urine

• Urinating in small amounts

• Seeming restless 

• Accidents outside of the litter tray

• Signs of discomfort or vocalising while urinating

UTIs can become a medical emergency, particularly in males who become blocked, so it’s important to get your cat checked quickly if they’re showing any of these signs.

In preparation, we’d recommend that you track your cat’s water intake and litter box habits. A simple record of how often they urinate and drink can help your vet to make a faster, more accurate diagnosis.

Non-serious causes

Before worrying about underlying health issues, it’s worth remembering that there are lots of everyday reasons why your cat might drink more water than usual. 

Changes in the weather, diet, activity levels, or routine can all affect how much they drink.

Hot weather

Just like us, cats get thirstier when they’re hot. So on warmer days, it’s completely normal for them to gravitate to their water bowl more than they usually would.

In particular, short-haired kitties, like Siamese or Sphynx cats, are more sensitive to the heat, so they’re even more likely to increase their water intake when the temperature’s higher. Adding a couple of ice cubes to their water bowl can help cool them down, as well as cooling mats and frozen cat treats.

Diet changes

If your cat’s recently switched from wet food to dry kibble, they might just be drinking more to make up for the water reduction in their diet.

Plus, some cat foods have a higher sodium content than others. Salt increases thirst, so it’s worth taking a look and comparing ingredient lists if you’ve recently changed brands. 

If it is higher in their new food, it’s nothing to worry about - but it could explain your cat’s extra trips to their water bowl.

Increased activity

Extra playtime, excited zoomies, or lots of outdoor exploring can naturally make your cat thirstier. This can depend on how much you’re interacting with them, how much fun they’re having out and about in the neighbourhood, and how far they’re travelling.

For active breeds in particular, drinking habits tend to fluctuate a lot, depending on the day’s particular shenanigans. Bengals and Abyssinians, we’re looking at you guys.

Stress or environmental changes

Cats thrive on routine, so changes in their environment can cause them stress and temporarily affect their behaviour - including how much they drink. 

This can include things like moving house, welcoming a new pet, or shifting their daily schedule. 

You should find that in a day or two, when they’ve come round to the change and feel more settled, they’ll be back to their usual self.

All of the above non-serious causes are typically short-term, meaning their drinking habits should return to normal as the weather, their routine, and lifestyle return to their baseline. 

However, if your cat’s still drinking excessively after a couple of days, it’s important to get them checked by a vet to make sure nothing more serious is going on.

Why is my senior cat drinking so much water?

Older cats are more prone to chronic conditions like kidney disease and hyperthyroidism. 

If your senior cat is drinking noticeably more, it’s worth monitoring for additional signs such as weight loss, lethargy, or changes in appetite. These symptoms often develop gradually, making them easy to miss at first.

Why is my kitten drinking so much water?

Kittens are naturally more active and may drink more as they grow and explore.

However, excessive thirst in a kitten is less common and should be taken seriously, especially if paired with diarrhoea, vomiting, or low energy.

My cat’s urinating much more than usual

If your cat’s drinking more, you’ll probably notice they’re urinating more frequently too. 

This combination, known as polydipsia (excessive drinking) and polyuria (excessive urination), comes hand in hand. It’s only natural - what goes in must come out! 

Sometimes you might only spot your cat urinating more, rather than drinking more. Depending on the cause, with some health conditions, increased urination can begin first and then excessive drinking can follow shortly after, and vice versa.

And, the truth is, it can be much easier to keep track of your cat’s litterbox habits, rather than their water intake. Frequent urination is often a great telltale sign that your cat’s drinking much more than usual. You may notice:

• More frequent trips to the litter box

• Larger clumps in the litter

• Accidents outside the litter tray

When should I see a vet for my cat’s excessive drinking?

Whilst it’s often nothing to worry about, excessive thirst can be a sign that your cat’s unwell, and early intervention is always best for effective treatment - as well as getting them comfortable and like themselves again as quickly as possible.

If you notice any of the below, it’s time to get your cat booked in at the vets:

• Your cat’s drinking has increased suddenly and noticeably for two days or more

• There are additional symptoms like weight loss, vomiting, or lethargy

• You notice increased urination or litter box changes

What will the vet do?

The vet’s treatment will depend on the reason behind your cat’s excessive drinking. 

They may advise:

• Dietary changes, such as switching to wet food or prescription diets.

• Medication for conditions like hyperthyroidism or infections.

• Fluid therapy is often used in kidney disease management.

What if there’s nothing wrong?

If your cat gets the all-clear, your vet may decide that they’re drinking more due to warmer weather, increased activity, or adjusting from a wet to dry food switch. 

If this is the case, they’re drinking more simply because their body needs it. It’s always best to rule out serious causes, though - you’ve done the right thing getting them assessed to be sure!