Help! My Cat Is Drinking A Lot

Updated November 23, 2021

‘At A Glance (Details Below)’ What To Do

If A Cat Drinks More Than Usual

  1. It could be due to diabetes, kidney or thyroid disease
  2. These are all easily diagnosed on routine blood & urine testing
  3. The top three causes can all be managed or treated if detected in time
  4. If testing is normal, there’s usually nothing to worry about

Now dive deeper…

All jokes aside, cats really do have a drinking problem. I’ve talked before about cats not drinking enough water but that’s nothing compared with what happens when cats are too thirsty.

A cat who starts drinking or urinating more than they used to is almost certainly in big trouble. The good news is, it’s not an emergency and there’s plenty you can do if you find the cause before your cat gets sick.

Why Do Cats Drink Too Much?

There are five common reasons why you might notice your cat wanting more water. Read more about each at the links.

The last one should be obvious but it really is surprising how much more water cats need to drink on dry foods. Diarrhoea should also be obvious but many cats don’t use litter boxes so you might need to go poking about (quite literally).

Whatever the cause, drinking excessively is a sign to take seriously. Any change in a cat’s behaviour almost never happens just by chance. If there’s one thing I want you to take away from this blog, that’s it.

More About Kidney Disease

I’d like to say a few more words about kidney disease; it’s the most common cause of drinking excessively and the most common illness of older cats. Most cat lovers will at some point have to face it so it’s good to be prepared.

Correct treatment of kidney problems depends on knowing both the stage of the disease and the unique features of each cat. It can be fiendishly complex and no two cats are treated the same. You can read all about this at our kidney disease page but here’s a quick summary of what your vet should be thinking and doing.

Tests For Kidney Problems

  • Blood and urine testing. No animal can be diagnosed as having kidney failure without both of these. That’s because dehydration from other causes looks exactly the same until you check the urine concentration. Blood tests like these also show us related problems like low potassium or high phosphate.
  • Blood pressure measurement. Kidney cats are often hypertensive; if you don’t fix this, they can go blind from retinal detachment and kidney problems worsen quickly.
  • Sterile urine culture. Not only are kidney infections more common than realised, they are great to discover. My own cat had one and by controlling it, her kidney problem got better, not worse.
  • Urine protein: creatinine ratio. Urine protein loss is a sign of glomerular damage and can be treated just by adding another tablet.

Read how to collect a urine sample here.

Treatment Of Kidney Disease

It all depends on the individual. The most important therapy for the majority of cats is a change to a renal support diet. By reducing blood phosphate levels and adding extra nutrients, these diets can make a huge difference to your cat’s lifespan and quality of life.

There are also several drugs we use to treat cats with kidney problems, though most cats only need a few of these.

  • Phosphate binders are needed if the special diet doesn’t do enough on its own
  • Potassium supplements fight the increased loss of this electrolyte from the kidneys
  • Drugs like benzepril or telmisartan reduce glomerular hypertension
  • Antihypertensives like amlodipine control high blood pressure
  • Appetite stimulants help cats maintain body weight, especially in later stages

The most important thing, however, is close monitoring. There’s no such thing as ‘wait and see’ with a cat who might have kidney problems. If they get sick, the faster we get them rehydrated the better their chances are of returning to normal.

Early detection is even more important. So if you have a cat who starts drinking more, even if they haven’t yet lost weight, let us take a look! It might be nothing, or it might just be the clue that saves your cat.

Related: Why cats pee inside

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here. The information provided here is not intended to be used as a substitute for going to the vet. If your pet is unwell, please seek veterinary attention.

11 Replies to “Help! My Cat Is Drinking A Lot”

  1. My cat, has started drinking lots of water, and has a bumpy rash on her neck and back, my problem is she is not a very friendly cat and I have not been able to take her to a vet. When she was very young I had her spayed and shots were given then, she stays in most of the time. She is approx. 11yrs old . I need to be able to take her to a vet. I would appreciate any advice you can give me.

    1. Hi Barbara. You can get something from your vets that will calm your cat for the trip. Then you’ll just need to work out how to give it to her if you can’t hide it in her food.

  2. My hairless sphynx is 1 and has always drank a lot of water and has pretty much always had v runny

    I think I will get her blood tested

    1. Hi Oscar. If the word after runny was going to be poo then that’s probably where the water is going. Therefore, some faecal testing would be helpful as well or some dietary trials.

  3. I noticed that my cat Luna, was excessively thirty yesterday.
    So I figured there would be a huge pee, in her box, when I woke up.
    Suprizingly, She hadn’t used her litter box all night! Which I don’t think she has ever NOT used it, since I’ve had her. So, now I am getting a a little concerned.
    Should I be concerned?
    Any advice would be much appreciated! Thank you,

    1. Hi Meredith. I can’t explain that either, but I always say that if anything seems unusual about your animal, trust your instincts and go to the vet for a check up just in case. You’re often right.

  4. Just before Christmas my 15 yo spayed persian started loosing weight and vomiting drinking a lot but not eating much. She mostly slept a lot. I took her in to the vet and after blood work was told she her kidneys had stopped functioning and even a blood transfusion wouldn’t help. It was recommended I euthanize her, she purred while I held her till her heart stopped. After reading this- was there things that could have been done to extend her life, did I euthanize my ❤️Cat for nothing?! No other options were discussed. No urine was taken. Did my vet get lazy?

    1. Hi Tessa. I can tell from the fact that she was anaemic that she was in stage 4 CKD. Therefore the right decision was almost certainly made. It’s always hard choosing euthanasia because there’s always a small chance they can improve with treatment, but there’s also a high risk that you just prolong the suffering.

    2. The same thing happened to my 19 1/2 yr old siamese cat. They offered an option to give her a drug that might help for “the weekend” or maybe “a few more months”. I chose to have her put down because she _lived a good life_ and it would only be selfish to try to keep her alive (while suffering) for my own benefit. Had your persian been 2 or 5 years old it might have been worth trying something else. I think you did the right thing. God bless you for not being selfish.

  5. My cat is 13 years old lately she poo in most rooms only using her kitty litter bin for peeing she die to see vet on 9 .10.20

    1. Hi Frank. That’s a hard one, and if the faeces are normal in appearance it’s most likely to have a behavioural cause. If so, the solution will require investigation of environmental factors such as litter type, cleanliness, position, presence of other cats, other stressors, and your cat’s pain level re arthritis.

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