This page is not veterinary advice. Paw Multiverse is not a veterinary practice. We cannot examine, diagnose or treat your animal. There are no medicines here, no doses, no home remedies and no treatment steps, on purpose. If your pet is unwell, has swallowed something, or has changed in a way you cannot explain, ring your vet or your nearest emergency clinic and let them decide. Full disclaimer.
A cat that has started drinking more is one of the few changes an owner can spot from across the room, and one of the few that veterinary sources treat as a reason to book an appointment rather than to watch and wait. That combination makes it worth understanding properly. This page covers what the change means in clinical terms, why it is genuinely hard to see in cats, what to record before you ring, and where our own line is on what we will and will not publish.
The two words the practice will use
Polydipsia means increased water intake. Polyuria means increased urination. International Cat Care uses both terms and pairs them, and the pairing is the point: water that goes in has to come out, so the two almost always move together. A cat that is drinking more and urinating the same amount is a different picture from a cat doing both, and your vet will want to know which you are looking at.
Veterinary Specialists puts the significance plainly in its own fact sheet, describing increased drinking as usually considered an important sign and an indicator of the need for investigation. Not a symptom to monitor. A sign that triggers tests.
Why there is no number on this page
Both of the veterinary sources we used for this article publish a threshold in millilitres per kilogram of body weight per day. We have read it, we have linked to both sources, and we are not reproducing it here. That is a deliberate editorial decision and you are entitled to know the reasoning.
A published threshold in an owner facing article does two harmful things. It gives a worried owner a reason to wait, because a cat drinking a bit more but under the line reads as fine, and the trend matters more than any single day. And it invites home measurement in exactly the household where home measurement is least reliable, which is most households, for reasons set out in the next section. The number belongs in a consulting room where someone can weigh the cat accurately, ask what else is going on, and put a blood and urine result next to it.
If your cat is drinking more than it used to, that is the finding. You do not need to quantify it to justify the phone call. The same principle governs the rest of this site, and it is why the water intake calculator here is framed the way it is.
Why increased thirst in cats is harder to see than in dogs
Cats are quietly built to defeat the observation. Several things stack up at once.
International Cat Care notes that cats eating wet food take in a large share of their water with their meals and drink visibly less as a result, while cats on dry food drink more. Change the food and the visible drinking changes without anything happening to the cat. If you switched brands, textures or feeding routines in the same period you noticed the drinking, say so at the appointment, because it changes what the observation means.
Then there is access. A cat with a cat flap has water sources you cannot audit: puddles, ponds, water butts, a neighbour who leaves a bowl out. A cat in a multi cat household shares bowls, so a rising bowl consumption may not belong to the cat you are worried about. And cats that have discovered a dripping tap, a shower tray or a toilet may be drinking substantial amounts in a place with no bowl to measure.
The consequence is that the reliable signal is usually not the volume. It is the change in behaviour around water: a cat that now waits by the tap, a cat that has started drinking in front of you when it never did, a cat that has begun visiting a bowl in a room it used to ignore. Those are noticeable without a measuring jug and they are worth reporting.
The other half of the picture is in the litter tray
Because polyuria travels with polydipsia, the tray often shows the change earlier and more clearly than the bowl does. You are looking for a shift in your own routine, not an absolute quantity: the tray needing attention more often than it used to, clumps that are noticeably bigger, litter needing topping up sooner, a cat that has started getting up in the night, or a cat that has begun missing the tray in a house where it never did.
If your cat goes outdoors and does not use a tray at all, this signal is invisible to you and it is worth saying so to the practice, because it tells them which observations they can trust from you and which they cannot. If tray behaviour has changed for reasons that might be nothing to do with thirst, the litter box troubleshooting guide covers the ordinary causes.
What you can see, and what you cannot conclude
WHAT YOU CAN SEE WHAT IT MIGHT REFLECT WHO DECIDES
---------------------- ----------------------- -----------
Bowl empties faster --> more water in you observe
vet decides
Litter tray heavier --> more water out you observe
or changed more often vet decides
Cat now waits at the --> a new drinking habit, you observe
tap or fountain or a bowl problem vet decides
Cat drinks where it --> change in behaviour, you observe
never used to not just in volume vet decides
Any of the above --> a pattern worth the vet,
plus a second change investigating with tests
------------------------------------------------------------------
Everything in the left column is yours to record.
Nothing in the middle column is yours to conclude.
The right column never changes.
What increased thirst can be associated with
This section names conditions because both sources name them, and because an owner who has heard the words before is less frightened when they come up in the consulting room. It is not a diagnosis, it is not ordered by likelihood, and nothing here tells you which one applies to your cat, because that is not knowable from a website.
International Cat Care lists kidney disease, diabetes mellitus, hyperthyroidism, high blood calcium and liver disease among the causes of increased thirst in cats, and notes that dehydration from vomiting, diarrhoea or warm weather can also raise drinking without disease being involved. The Veterinary Specialists fact sheet, which covers dogs and cats together, adds kidney infection, pyometra, overactive adrenal glands, disruption to antidiuretic hormone production, and primary polydipsia, meaning an increased drive to drink that is not driven by fluid loss.
That list is long and it spans conditions with very different outlooks. The Veterinary Specialists sheet says as much: the outlook fundamentally depends upon the diagnosis and varies from very good to very poor. Which is precisely the argument for going early rather than reading further.
What the vet will actually do
Knowing the shape of the appointment takes some of the dread out of it. Both sources describe the same starting point. International Cat Care says the vet will usually take a blood and urine sample to determine the underlying cause. Veterinary Specialists describes standard blood and urine screens first, because those catch the most common causes, followed if needed by imaging of the internal organs, urine culture, and tests of hormone function. It also describes a water deprivation test, used to assess how well the kidneys concentrate urine and respond to antidiuretic hormone.
That last one is the reason we will not tell you to restrict your cat’s water while you wait. Withholding water is a controlled clinical procedure that a practice runs under supervision for a specific diagnostic reason. It is not something to attempt at home, and nothing on this page should be read as suggesting it. Before you call the vet sets out what to have ready so the first appointment is productive.
Take this to the appointment
The most useful thing you can bring is a record rather than a theory. Vets are used to owners arriving with a conclusion and no observations. The reverse is far more valuable.
Print this and take it to the appointment. It is an observation record, not a test.
The change itself
Water going in
Water coming out
Everything else that changed
Things that are not, on their own, warning signs
Worth saying, because worry expands to fill available space. A cat that prefers a dripping tap to a bowl is displaying a preference documented by International Cat Care, which notes that some cats like to drink from moving water. A cat that will not drink next to its food is doing something the same source describes as normal. A cat that dislikes deep bowls, or plastic ones, or bowls where its whiskers touch the sides, is also behaving as that guidance describes.
None of those is a health signal. All of them can change how much drinking you happen to witness, which is a different thing. If you have recently moved a bowl, changed its material, or added a fountain, the amount you see your cat drink may have changed while the cat has not. Note it, and say so.
Equally, warm weather raises drinking, and International Cat Care lists it among the non disease causes. We are not going to tell you what to do about a hot cat here, because that is covered separately and because heat guidance is exactly the kind of thing that should not be improvised from a behaviour article. The heat emergency page is where that belongs.
Related reading on this site
If you want the mechanics of how cats drink and why bowls matter, why cats hate water covers the evolutionary and practical picture. The water intake calculator and the dog version both exist to frame the question rather than to give you a target. For dogs, panting is the equivalent easily misread signal.
For general change spotting, pet body language covers what an animal shows before it shows anything obvious, and sleeping patterns is the other change owners most often notice and most often dismiss. If your cat is elderly, the senior care guide is dog focused but its argument about baselines applies to both species. And if you are keeping records for the first time, the pet care plan and the emergency folder are where they should live.
Where these facts come from
Every claim above was read on the source named beside it, on 4 August 2026. The definitions of polydipsia and polyuria, the wet against dry food point, the list of associated conditions in cats, the non disease causes and the blood and urine sampling come from International Cat Care. The bowl material, bowl shape, whisker contact, placement away from food and moving water preferences come from International Cat Care’s guidance on encouraging cats to drink. The framing of increased drinking as an indicator for investigation, the wider list of causes, the description of blood and urine screens, imaging, urine culture, hormone testing and the water deprivation test, and the statement that outlook depends on diagnosis, come from Veterinary Specialists. Both sources publish a numerical threshold. We have chosen not to reproduce it, and have explained why above rather than quietly omitting it.
