Last Updated: 05/08/2026
Why is my Cat Drinking More Water?
Noticed your cat at the water bowl more often? Find out what's normal, what causes polydipsia, and when it's time to call the vet.
Author: Dr Gillian Hill BVSc (Hons)
Reading Time: 3 minutes - short read
You've noticed your cat making more trips to the water bowl. It's easy to dismiss at first, but you're right to pay attention. Increased thirst (called polydipsia) is one of the most reliable early signs that something is going on internally, and catching it early makes a real difference.
What's normal for cat water intake?
Most cats need around 40 to 60ml of water per kilogram of body weight each day, though cats on wet food get most of their water through meals and drink less from the bowl. The clinical threshold for polydipsia is 100ml per kilogram of body weight per day - so for a 4kg cat, more than 400ml daily is a flag for concern.
What are the most common reasons cats drink more water?
Any cat drinking more than usual should be seen by a vet, particularly if water intake exceeds 100ml per kg of body weight daily. This is the clinical threshold for polydipsia and is commonly associated with chronic kidney disease, hyperthyroidism, diabetes mellitus, and sometimes urinary disease.
Chronic kidney disease (CKD)
CKD is one of the most common conditions in older cats. As the kidneys lose their ability to concentrate urine, cats compensate by drinking more. You might also notice pale, dilute urine and more litter box visits as well.
Read more in Kidney Disease in Cats and Managing Kidney Disease in Cats.
Hyperthyroidism
An overactive thyroid speeds up the metabolism, causing increased thirst, weight loss despite a good appetite, hyperactivity, and a scruffy coat. Very common in middle-aged to older cats and very treatable once caught.
Learn more in Hyperthyroidism in Cats.
Diabetes mellitus
Cats can develop diabetes when their body doesn't produce or respond to insulin properly. Increased thirst and urination are the hallmark signs, often with weight loss and increased hunger.
Learn more in Diabetes in Cats.
Urinary disease
Cats with FLUTD (Feline Lower Urinary Tract Disease), especially urinary tract infections, may visit the litter box frequently with small amounts of urine, and sometimes drink more. UTIs are relatively uncommon in cats, but any straining, blood in the urine, or toileting outside the box all warrant an urgent vet check.
Read more in FLUTD in Cats.
What else can cause a cat to drink more water?
Less common causes include hormonal diseases like acromegaly, liver disease, electrolyte disturbances and infections such as pyometra.
Hot weather, a recent food change or high-sodium diet, or a dry food only diet where cats compensate for lower moisture intake can also cause a cat to drink more. Adding some wet cat food is an easy way to boost hydration. Our guide on how to increase your cat's water intake has more practical tips.
How can I monitor my cat's water intake at home?
Fill the water bowl with a measured amount each morning and subtract what's left 24 hours later. Do this over 2 to 3 days to get a daily average. Note whether your cat is also urinating more frequently, as this usually goes hand in hand. If you have multiple cats, temporarily separating them and their water stations makes it easier to track individual intake.
What will the vet check for?
Most vets will run blood tests (kidney function, thyroid levels, blood glucose) and urinalysis to assess urine concentration, glucose and any signs of infection. Blood pressure is often measured too, particularly in older cats. In most cases these give a clear picture.
Any cat drinking more than usual is worth a vet visit, especially above 100ml per kg of body weight per day. The most common causes are chronic kidney disease, hyperthyroidism and diabetes, all manageable when caught early. A few days of measured water intake before the appointment gives your vet a useful starting point.
FAQs
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History
Our experts continually monitor the health and wellness space and we update our articles when new information becomes available.
Thu 6 Aug 2026
Written by Dr Gillian Hill BVSc (Hons)Dr Gillian Hill BVSc (Hons)
Veterinarian
Dr. Gillian graduated from the University of Sydney in 2005 with a Bachelor of Veterinary Science. She worked in a number of small animal clinics, before joining the Pet Circle Vet team in 2020. Dr. Gillian has special interests in ultrasonography, surgery and behaviour. Her favourite part of being a vet is being an advocate for the animals. She loves helping owners to make the best, evidence-based decisions for their pets, and seeing the beautiful bond that people have with their fur-babies.
