Cats drink different amounts of water depending on their diet. Cats fed wet food will get a large proportion of the water they need from their food (just like their wildcat ancestors), whereas cats fed mainly on a dry diet will drink more water. If you are worried that your cat isn’t drinking enough, visit our advice page on how to encourage your cat to drink.
If you notice that your cat is drinking more than usual, this may indicate that something is amiss. Increased water intake is known as ‘polydipsia’.
The most common causes of increased thirst and drinking are:
- Kidney (renal) dysfunction
- Liver (hepatic) disease
- Diabetes mellitus (‘sugar diabetes’)
- Hyperthyroidism (over active thyroid)
- Urinary tract disease
- Compensatory increased water intake eg, losses after vomiting or diarrhoea
If you are worried about how much your cat is drinking, it can be useful to monitor their water intake for 24 hours. You can measure their water intake over a 24-hour period by filling the cat’s water bowl(s) to the brim, measure the amount of water left over at the end of the 24-hour period and take this away from the volume of water in the full water dish(es) (this may be more difficult to do if you have more than one cat in the household). Polydipsia is defined as a cat drinking more than 100ml per kg of their bodyweight per day, but any cat that is drinking more than usual should be seen by a vet, as this may indicate that something is amiss. Of course, let the vet know the amount your cat is drinking if you have measured it.
As there are many reasons why your cat has an increased thirst your vet will usually take a blood and urine sample to work out the underlying cause. Once the cause of polydipsia is determined, then suitable treatment can begin.