Cats often go through short periods of drinking more water than usual, and this is perfectly normal. However, a noticeable and persistent increase in thirst can sometimes be an early sign of illness in cats. If you have concerns about your cat drinking more than normal, it’s always best to consult a vet for individual advice and guidance.

Cats, just like us, drink more water when thirsty. There are many reasons cats can become thirstier. Some causes are linked to conditions that need veterinary investigations and treatment. Especially if drinking more is accompanied by other changes, such as weight loss and appetite changes. Drinking more water also means your cat will pee more. A simple urine test can often help you and your vet find out the reason why your cat is drinking more. 

What to do if your cat is drinking more? 

Cats usually drink around 30-45 ml/kg body weight in 24 hours, depending on diet, environment and activity levels. While numerical guidelines are useful in defining these limits, cats don’t always read the textbooks. Instead, what is important is noticing any changes in your individual cat's normal drinking and urinating behaviour and acting promptly.

So a young 3kg cat will drink approximately 120ml of water a day, and a 5kg cat will drink 200ml. This water can come from drinking from the bowl, but also through their wet food. Some cats are not often seen drinking as they consume adequate fluids through their food instead. 

If your cat is drinking more, we need to rule out the simple reasons. Then find out how much they are drinking and if anything else has changed.

• Check that your cat’s bowl gets filled regularly, so they’re not gulping water because they’ve been waiting for it.

• Clean bowls regularly and give options of sources. Cats can be very particular about cleanliness and the types of bowls. Some prefer running water, like a fountain or a drip tap.

• Find out how much they are actually drinking. Measure water into their water bowl and keep it topped up. Record how much you add and how much is left after 24 hours. Try to prevent them from drinking from outside while you’re doing this.

• Check how much your cat drinks over several days to see if there’s a pattern, like after eating, after playing or being outside, or early morning.

• Collect a urine sample from the litter tray in a clean jar or specimen bottle from the vet. If your cat drinks more, their urine is more dilute. The vet can check this and look for other clues to the underlying cause. 

Common causes of drinking more in cats

The most likely reasons for empty water bowls will be ‘physiological’. This is vet-talk for drinking more because your cat’s warm or exercised more, or because they’ve eaten.

• Cats lose water naturally when they breathe, which helps cool them down if they’re hot or because they've been having the zoomies. 

• Moving from a wet to dry food means your cat gets less water from their dinner and needs more from their water bowl.

• Activity levels and environment also influence thirst; more active cats and those in warmer climates need a higher water intake.

Illnesses that cause drinking more than normal in cats:

• Vomiting and diarrhoea: dehydration

• Eating something harmful: grapes, chocolate, anti-freeze, lilies

• Diabetes 

• Chronic kidney disease

• Hyperthyroidism

• Urinary tract infections

• Electrolyte or hormonal imbalances

• Certain medication use e.g. steroids or diuretics

• Liver disease

When to worry if your cat is drinking more

Call your emergency vet if your cat is drinking more and:

• May have eaten something harmful

• Has very severe vomiting and diarrhoea, especially with blood

• Seems vacant or confused

• Having difficulty urinating or straining

• Having breathing difficulties or open-mouthed breathing

• Weak or collapsed

• Having seizures

Speak to a vet as soon as possible if your cat is drinking more and:

• Losing weight

• Peeing more often, and the pee (urine) looks or smells abnormal

• Behaviour changes such as yowling excessively or walking with lowered haunches

• Has mild vomiting and/or diarrhoea
  

Can (and should) I prevent my cat from drinking more?

Don't restrict water when your cat needs it. This can be distressing and harmful for them.

Cats need to drink more to make up for the fluid they may be losing in urine, vomit, diarrhoea or panting. Preventing them from drinking will worsen dehydration and make them even sicker.

Protecting against possible underlying causes

Improve water intake:

• Ensure adequate water intake from water sources or wet food

• Keep bowls clean and provide multiple sources

• Provide access to both warm and cooler areas so your cat can choose a comfortable environment 

Illness:

• Visit your vet to diagnose and treat any underlying causes

• Keep all harmful substances out of sight, smell and reach of cats, especially as cats have expert climbing and jumping abilities

• Managing long-term illnesses can help reduce excessive drinking, even when the condition can’t be cured. These include chronic kidney disease and liver disease. But be aware—drinking more can also be an early sign that the condition is getting worse.

Things to look out for if your cat is drinking more

Warning signs that suggest there's something wrong when your cat’s drinking more include:

• Changes in eating habits

• Weight loss or a change in body shape

• Changes in smell or colour of urine, or litter tray habits

• Vomiting and changes in poo

• A new cough or open-mouth breathing

• Having less energy

How to help at home if your cat is drinking more

If your cat has a diagnosed condition such as hyperthyroidism, kidney disease, diabetes, liver disease or heart disease, they may naturally drink more than other cats. You can’t stop the extra thirst, but you can help them stay comfortable and healthy at home:

• Keep fresh water available from several different sources. This is especially helpful for older cats or those with specific preferences.

• Never restrict their water. Limiting water can make them very unwell, especially with kidney disease.

• Cats with chronic conditions often need to pee more. Have more litter trays than the number of cats in the house and keep them all clean to encourage use, or if preferring to toilet outdoors, allow frequent access.

• Give medications exactly as prescribed and keep up with any special diets. Good management of the condition often helps reduce excessive thirst.

• Monitor changes in drinking or peeing. A sudden increase can be an early sign that the condition is changing or worsening. Watch out for any new symptoms too. Keep notes to share with your vet. 

• Routine vet checks for blood tests or urine checks help catch problems early and adjust treatment when needed.

What's the vet treatment for cats drinking more?

Vet treatment is only necessary when there’s an underlying illness. Treatment will depend on the underlying condition. Some conditions may need lifelong medication and monitoring.

Your vet may recommend diagnostic testing, including blood and urine analysis. More complicated cases might also need imaging, such as X-rays or an ultrasound. 

Are some cats more likely to drink more than others?

Some cats are more likely to get hot more easily:

• Cats with long or thick coats, including Persian cats and Maine Coons.

• Short-faced cats (brachycephalic breeds), including the Persian cat and Exotic Shorthair breeds.

Difference in risk of other diseases:

• Older cats: higher risk of chronic kidney disease and hyperthyroidism.

• While both male and female cats are at risk of UTIs, male cats are more at risk of having a “blocked bladder”, where they have difficulty or an inability to urinate. This is an emergency situation.

Other reasons cats may drink more

There are some less common causes of drinking more, including:

• Psychogenic polydipsia: Increased drinking that starts as a habit or behavioural problem. Eventually, it also causes medical problems.

• Diabetes Insipidus: Also known as ‘water’ diabetes. A rare brain illness that means your cat can’t produce concentrated urine.

If you are at all concerned about your cats thirst or urinating behaviour talk to a vet to make sure all is well with your pet. Catching health problems early often leads to better outcomes and simpler treatment.