How much water a cat drinks is proportional to their size. On average, a cat drinks between 40 and 60ml of water per kilogram. However, sometimes they can drink much more than normal (polydipsia), and therefore urinate much more often (polyuria). While this doesn't always pose a problem, it can also turn into something much more serious.
Why does my cat drink so much?
Water consommation depends firstly on your cat's environment and diet. Dryer kibbles, by definition, make your pet thirsty faster so they tend to drink more. Similarly, when it's hot, they will feel the need to drink much more often to hydrate themselves.
A change in food is often responsible for your pet's behaviour changing. If the new kibbles you're feeding them are dryer them the previous ones, for example, then they will probably drink more.
However, some changes in behaviour should be a cause for concern. A cat that drinks a lot of water does so because they dehydrate quickly. Diarrhoea or vomiting may be the cause of the problem. These signs should always be taken seriously, even if they may be benign.
Chronic illnesses can also cause dehydration. Kidney failure, which is unfortunately very common in breeds such as Burmese or Ragdolls, as well as in aging cats, results in loss of appetite, fatigue, vomiting and weight loss. To compensate for kidney dysfunction, your cat will drink much more, and by definition urinate much more often. Chronic kidney failure is a serious disease with no cure.
It undoubtedly leads to the destruction of the animal's kidneys with its outcome always being fatal. However, there are palliative treatments that can improve the cat's quality of life.
Hyperthyroidism may also explain your cat's increased thirst. While some symptoms, such as weight loss or fatigue, are quite similar to those of kidney failure, your pet still has an appetite and eats a lot. Treatment with tablets or surgery can solve the problem.
Diabetes mellitus is sometimes the cause of behaviour change in cats. If your cat is getting thinner, but is eating all the time, then this could be a sign of the disease. Older male cats that are overweight, are much more affected than others. Diabetes mellitus is treated by insulin injections.
What do I do if my cat is drinking and urinating a lot?
Try first of all to analyse the context. Have you changed their food? Has there been an increase in temperature? If the answer is yes, you have your explanation.
However, if your cat's drinking and urinating habits are excessive, it's always better to consult your vet for peace of mind. An examination will allow you to get rid of all your worries, or perhaps shine a light on a serious problem that needs treatment.
Make sure to make a note of the symptoms, so that your vet can give the most accurate diagnosis possible. They will usually do this by taking a small blood sample.