What this means
Cats drink little, and many of them also take in water with their food, so a change can be hard to notice. A cat that drinks more usually shows it in daily life: the bowl empties faster, you refill it more often, the cat starts drinking from the sink, the bath or a dripping tap, and the litter box holds more or bigger wet clumps.
Thirst is rarely the only change. Cats are good at hiding that they feel unwell, so other changes alongside it, such as a smaller appetite, weight loss, more sleep or a neglected coat, are just as important as the drinking itself. Even if the cat seems lively enough, a thirst that stays raised for a while still needs checking.
You cannot work out the cause by looking: only a vet can find it, by examining the cat and running tests. It helps to write down when you first noticed the change and how many times a day the bowl needs filling. Do not limit your cat's water, and do not wait for other signs to appear.
Possible causes
These are things that can cause this sign. It is not a diagnosis, and they are not equally likely for your cat.
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Reduced kidney function
When the kidneys work less well, the body loses more water and the cat tries to make up for it by drinking. Sometimes this is an inherited disease that develops from a young age.
About the condition: Chronic kidney disease -
Diabetes mellitus
When the body cannot keep blood sugar under control, sugar leaves in the urine and takes water with it, so the cat drinks more. It may eat well and still lose weight.
About the condition: Diabetes mellitus -
Organ disease from a build-up of abnormal protein
In some diseases an abnormal protein collects in the organs, the kidneys among them, and disturbs how they work. The cat may drink more, eat less and seem tired.
About the condition: Amyloidosis -
Other internal or hormonal disease
Cats also drink more with other illnesses that can only be told apart by tests. That is why guessing is no use and it is better to show the cat to a vet.
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Hot weather or dry air
On a warm day or in a room with dry air a cat may drink a little more. If the raised thirst lasts for several days and the weather does not explain it, a vet should be asked.
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Something toxic or a reaction to a substance
A sudden, strong thirst is sometimes linked to something toxic the cat may have swallowed, or to the body reacting to a substance. In that case a vet is needed urgently.
What else to watch for
These observations help your vet build the picture faster. Note down what you saw and when.
- How many times a day the bowl needs filling, and since when
- Whether the cat drinks from the tap, the sink or other unusual places
- Whether the litter box clumps are bigger or more numerous
- Whether appetite or weight is changing
- Whether the cat sleeps more or grooms less
- Whether it also vomits or seems to have a sore belly
When to book a routine visit
Book a visit if your cat clearly drinks more for several days in a row, even if it otherwise seems well. The sooner you mention the change, the sooner the cause can be found.
Related conditions
Conditions whose entries mention this sign. The list is somewhere to read on, not a way to reach a diagnosis.
- Amyloidosis General health A condition in which an abnormal protein, called amyloid, builds up in the organs and slowly disturbs how they work. In cats it can settle in the kidneys, the liver or other organs, so over time these organs can start to work less well.
- Chronic kidney disease Kidneys and urinary tract A disease in which the kidneys slowly, over months or years, lose their ability to clean the blood and concentrate urine. It develops quietly, so its first signs are easy to put down to old age.
- Diabetes mellitus Hormones and metabolism A condition in which the body can no longer keep the level of sugar in the blood under control, because it makes too little insulin or stops responding to it. Without insulin the cells go hungry while sugar piles up in the blood and spills into the urine.
- Hyperthyroidism (overactive thyroid) Hormones and metabolism A disease in which the thyroid, a small gland at the front of the neck, makes too much hormone. The whole metabolism speeds up, so the cat loses weight even though it eats more than ever.
- Polycystic kidney disease Kidneys and urinary tract An inherited kidney disease in which fluid-filled sacs, called cysts, form in the kidneys. They slowly grow, press on healthy tissue and make it harder for the kidneys to work.
Body systems: General health Kidneys and urinary tract Hormones and metabolism