How much water should a cat drink

There are some things you might not think to mention to your vet at check-ups – and your cat drinking more or less water than usual is one of them. But if your cat’s drinking habits noticeably change with age, you shouldn’t just ignore this. While it’s important for our feline friends to stay hydrated, a cat drinking a lot more than they used to may be suffering from an underlying health condition. Here, we look at three common causes of increased thirst in older cats.

In a healthy cat, blood sugar levels are precisely balanced, and the pancreas produces just the right amount of the hormone insulin to help regulate the cat’s energy requirements. Diabetes occurs when too little insulin is produced (Type 1 diabetes) or because the body isn’t responding correctly to insulin production (Type 2 diabetes).

Type 1 diabetes is very rare in cats, but older or overweight felines are often diagnosed with Type 2, due to the pancreas becoming less efficient as they age. Male cats also appear to be at more risk, although vets are not yet exactly sure why.

Diabetic cats become very thirsty because there’s too much sugar in the urine, which, in turn, draws water out of the body.

Some breeds – such as the Burmese – are more vulnerable to diabetes than others. But for all cats, at every life stage, the risk lessens with good levels of activity (especially for indoor cats) and a complete, balanced diet.

As well as drinking a lot, diabetic cats may also display increased hunger, lethargy, excessive weeing and weight loss. In some cats, diabetes can affect the nervous system, so the animal finds it difficult to straighten its back legs. This is usually referred to as a ‘plantigrade stance’, and the condition makes walking and jumping very difficult.

It can be hard to monitor your cat’s water intake as they often drink (unseen) from puddles, toilets or dripping taps. But if you notice your cat drinking more and showing other related signs of diabetes, do speak to your vet as soon as possible.

Your cat’s kidneys do two things: filter waste from the body, and concentrate the urine when your cat needs to retain water (if they’re drinking less, for example).

Historically, the domestic cat evolved from animals in dry areas, such as Egypt. Due to this ancestry, and the frequent need to retain water in hot, arid climates, a cat’s kidneys work very efficiently. However, this also leaves them vulnerable if they do develop kidney problems. Given that the kidneys naturally deteriorate with age, older cats can often suffer from kidney disease and chronic kidney failure.

Extreme thirst is usually the first symptom of kidney disease in cats. But as the toxins build up in their blood, your cat is likely to eat less, feel nauseous or even be sick.

It’s important to seek your vet’s advice if you notice any of these symptoms. Accidental poisoning can also cause kidney damage in cats of any age. Anti-freeze is a common culprit, and should always be kept out of your pet’s reach.

Older cats can develop an overactive thyroid gland, which is a condition known as hyperthyroidism (unlike older dogs, which are more prone to hypothyroidism – an underactive thyroid gland).

Metabolic rate, vitality and coordination are all controlled by the thyroid gland – so if it’s working more frantically than it should be, your cat will be irritable and skittish, and may even pant. Other symptoms of hyperthyroidism include drinking and weeing more frequently, and losing weight, despite eating more.

Hyperthyroidism can occur in any breed, at any age, but it’s more likely to develop in cats as they get older. Your vet will be able to recommend thyroid medication that can help.

While these conditions may explain why an old cat is drinking a lot of water, there could be other causes, such as urinary tract infections, liver disease, or increased thirst after a bout of vomiting or diarrhoea.

As with any other marked behaviour change in older cats, such as disturbed sleep, it’s always a good idea to discuss any concerns with your vet.