Is My Cat Dehydrated?

Sandra C. Mitchell, DVM, DABVP
By Sandra C. Mitchell, DVM, DABVP on Feb. 3, 2022

Have you ever felt like your cat wasn’t drinking enough water or noticed that your cat wasn’t feeling quite up to snuff, and wondered if they might be dehydrated?

This is a very common problem in cats, especially those that aren’t feeling well.

Both very old and very young cats tend to be more prone to the effects of fluid loss. Middle-aged cats that are in relatively good health are often more resilient to the effects of mild dehydration than, for example, an older cat that already has multiple health problems.

Here’s what you need to know about dehydration in cats, including the signs, causes, what to do, and proper treatment.

What Is Dehydration in Cats?

Dehydration happens when cats are not drinking as many fluids as they are losing. Sometimes, this might be simply because they don’t feel well and aren’t drinking much, but other times, it can be caused by illness like vomiting or diarrhea.

As a rule, when a cat becomes dehydrated, they also experience changes (usually losses) in many electrolytes such as sodium, calcium, and potassium. Proper hydration and having the right electrolyte balance are extremely important for keeping a cat’s organs and tissues functioning properly. Severe dehydration can even lead to death.

Fortunately, dehydration in cats is fairly easy to recognize and usually straightforward to treat once the underlying cause is identified.

Signs of Dehydration in Cats and Kittens

Signs of dehydration can range from simple and mild to very complex.

Most cats that are dehydrated aren’t feeling well, so not only will you notice that they aren’t drinking normal amounts of fluids, but often they aren’t eating properly either. They will be lethargic, and not doing the normal things you might expect them to do. Some cats may appear to have sunken eyes, and if they are becoming severely dehydrated, occasionally they will pant, seem weak, or collapse.

Test 1: Check Their Gums

One way to check if your cat is dehydrated is to gently lift their lip and touch their gums. Just like human gums, they should be wet and slimy. If they are dry to the touch and seem a little tacky, your cat is most likely dehydrated.

Test 2: Skin Pinch Test

Another popular method to check hydration in pets is the skin pinch test. This test only works in young, healthy animals with elastic skin and is not as useful once cats age or develop chronic illness.

However, if you gently lift (or “pinch”) the skin over your cat’s shoulder blades and then let go, it should quickly snap back into position. If the skin on your cat’s shoulder blades slowly settles back into position instead of snapping, this may also be a sign of dehydration.

Causes of Dehydration in Cats and Kittens

There are many causes of dehydration in cats, but at the base of all of them is that your cat is losing fluid more quickly than they are taking in fluids.

All cats lose fluids continually through the day—even the simple act of breathing evaporates crucial fluids, and a large volume is lost each time a cat urinates. All the basic body processes require fluids, which is why proper hydration is critical for restoring balance.

Anything that upsets this balance is likely to lead to dehydration:

  • Not eating or drinking as much or at all. Some of the more common causes of dehydration include anything that causes your cat to not eat and drink properly. If your cat isn’t taking in fluids, but still using them, dehydration happens quickly.

  • Vomiting and diarrhea. In these cases, your cat is losing fluids quickly and may not be feeling up to drinking or eating to replace them.

  • Diabetes and renal disease. These are two very common diseases in cats that cause increased water loss, which can quickly result in dehydration.

  • Fevers or traumatic injury. These will both often cause a cat to become dehydrated.

  • Hot weather and dry air. These can both lead to dehydration with time.

The degree of dehydration usually varies depending on the cause, with mild diseases resulting in more mild dehydration.

Why Is Dehydration in Cats a Serious Issue?

Veterinarians take dehydration seriously because your cat’s body needs water to successfully carry out virtually all the body processes. If there is not enough fluid or electrolytes to get the job done, organ systems can begin to shut down, waste accumulates in the bloodstream, and the situation can become critical. Fluids can be lifesaving for dehydrated animals.

In addition, cats simply feel unwell if they are dehydrated. An animal that isn’t feeling well won’t eat and drink normally, which compounds the problem. Proper hydration is at the core of good health.

Some animals are more sensitive to the effects of dehydration, such as kittens, senior cats, and cats with other health conditions. These more fragile animals can get into trouble quickly if they become dehydrated. A cat with diabetes, hyperthyroidism, or inflammatory bowel disease will need to be watched more closely for dehydration than a fully healthy cat.

What to Do If Your Cat Is Dehydrated

If you think that your cat is dehydrated, call and go see your veterinarian immediately. It can be difficult to judge how severe the dehydration is, and your veterinarian will be better equipped to do that as well as to determine the underlying cause of dehydration.

DO NOT force water on your cat or to try to use a dropper to give your cat water or food. It is possible to accidentally administer the fluids into the lungs, resulting in severe pneumonia.

It is okay to offer your cat canned food, tuna made for human consumption, water, and Pedialyte if you suspect that they are dehydrated. If your cat won’t take the fluids voluntarily, just wait until you can get to the veterinary hospital.

Treatment for Dehydration in Cats

Veterinarians will want to do a full examination on any kitty that is dehydrated to look for signs of overall disease and underlying conditions that may have triggered dehydration.

As a rule, your veterinarian may also want to run some laboratory tests, including blood and urine, to determine the severity of dehydration as well as the underlying cause. Additional testing may be recommended, depending on the situation.

Treatment will also vary. Mild dehydration and many conditions are often treated with fluids given under the skin (called subcutaneous fluids), which is generally performed on your cat as an outpatient procedure.

Sicker animals that are more fragile or more dehydrated may need to be hospitalized to have an IV catheter placed so that the fluids can be given directly within the bloodstream. Very dehydrated animals can require several days to regain normal hydration.

How to Keep Your Cat from Getting Dehydrated

Taking proactive steps to prevent dehydration in cats is worth the effort. Checking what your cat is eating/drinking twice a day will help you understand their trends and spot trouble before it becomes serious.

Since canned food has much more fluid content than dry food, it is often preferred, particularly for cats that are prone to dehydration. If your cat is at least eating their wet food, we do not have to worry quite as much about how much they are drinking, because they will be getting the fluids in their foods.

On average, cats should drink approximately 4 ounces per 5 pounds of body weight.

If your cat is eating primarily dry food, this will all need to come from the water bowl. However, if your cat is eating mostly wet food, they will probably drink very little water since the moisture in the wet food is adequate. With wet food, if your cat is eating normally, you can also assume that they are properly hydrated for the most part.

Many cats are picky about their water sources, so make sure there is always fresh water available, and that you clean the water bowl frequently. Some cats prefer running water, and fountains are quite popular with many cats. Other cats love the dripping of water from a faucet. Find out what your cat likes, and make sure that it is always available.

When it comes to dehydration in cats, the best rule of thumb is, “When in doubt, check it out.” Dehydration can spiral quickly, so if you’re not sure if your cat has enough fluids and isn’t eager to drink more when you offer them, schedule an appointment to have your cat checked out. Better to be safe than sorry!

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Sandra C. Mitchell, DVM, DABVP


Sandra C. Mitchell, DVM, DABVP


Sandra Mitchell is a 1995 graduate of the New York State College of Veterinary Medicine. Since graduation, she has worked in many fields...

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