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It’s no secret that cats struggle to drink enough water. To help get more insight into this issue, we turned to betterpet vet Michelle Diener, DVM. Here’s what she had to say.

Why is dehydration in cats so common?

Dr. Michelle Diener: The domestic cats of today evolved from wild cats that used to live in the deserts of the Eastern Hemisphere in such countries as Egypt, Africa, and Greece. Cats have the ability to conserve some water and have a decreased drive to drink water based on the lifestyle their ancestors lived in the arid deserts. This is why cats don’t drink enough water and often become dehydrated.

While dogs will drink water when they’re thirsty to maintain their hydration, cats are slower to do so. They don’t have the desire to drink water like dogs do.

How much should the average cat drink per day?

MD: The amount of water a cat should drink depends on their body weight and the type of diet they’re fed. The average adult cat weighs 10 pounds and should drink roughly one cup of water per day. However, some of that water may be from a cat’s diet. Canned (wet) food contains significantly more moisture than dry food, so the type of diet a cat’s fed will impact how much extra water a cat should consume. Cats that eat canned food will drink less water from their water bowls than cats that eat only dry food.

How often should a cat owner refresh their pet’s water bowl(s)?

MD: Cat owners should provide their pet with fresh water daily. There are a few reasons why this is important. For starters, fresh water is more appealing to a cat. Also, if water is left in a bowl for too long, it can become contaminated with mold, giardia, and bacteria. By changing water daily, a pet owner will be able to closely monitor the amount of water their cat consumes on a daily basis.

Any decrease or increase in your pet’s thirst may be a sign of a medical condition, especially if it continues for several days. A pet owner may be able to detect that a cat has an illness before other symptoms develop based on their cat’s daily water consumption. Alerting a local vet about a change in water consumption can be vital to diagnosing a cat’s medical condition in an early stage, which will improve their prognosis.

What are some of the most significant health risks for cats that don’t drink enough water?

MD: When cats become dehydrated, they lose their ability to regulate their body temperature. Their heart can’t pump efficiently enough to allow adequate blood flow throughout the body, which is required to maintain warmth. Dehydration also causes a deficiency in electrolytes. Dehydrated cats often have a deficiency in sodium, chloride, and potassium, and because of these deficiencies, they lose the ability to pump nutrients into cells throughout their body.

Severe dehydration can be life-threatening because it can lead to organ failure. The heart, kidneys, and liver can shut down due to electrolyte abnormalities, decreased heart function, and poor blood circulation throughout the body.

How can cat owners know if their pet is dehydrated? At what point should they head to the vet?

MD: The following are a few ways to tell if your cat is dehydrated:

  • Skin tent test. Gently hold up some of your cat’s loose skin on the back of the neck and then release it. In well-hydrated cats, the loose skin will instantly spring back to its original position. The skin of a dehydrated cat will take longer to fall back into place and will appear tented above the neck. This is referred to as a skin tent test.
  • Tacky and dull gums. If your cat will let you, check their gums. A well-hydrated cat’s gums should be pink and shiny. Touch the gums with your finger. If your finger sticks to the gums, then the gums are tacky, which is a sign of dehydration.
  • Sunken eyes. A cat’s eyes will sink into their eye sockets when they’re severely dehydrated.
  • Decreased food and water intake. If your cat hasn’t touched their food or water in over 48 hours, then dehydration is likely.
  • Decreased urinary output. Monitor your cat’s urinary output daily. If a cat is urinating less frequently, this can be a sign of dehydration and may be due to kidney disease or urinary obstruction.
  • Ongoing vomiting or diarrhea. If your cat has several episodes of vomiting or diarrhea in 24 hours, then a vet visit is important to determine the underlying cause. Ongoing vomiting and diarrhea cause a cat to lose bodily fluids, and they won’t be able to drink enough water to keep themselves hydrated.
  • Dry, hard stools. Cats that have dry, hard bowel movements are often dehydrated and prone to constipation. Check your cat’s litter box daily to make sure their stools are moist and formed.

👉 If your cat is exhibiting any of the above signs of dehydration, it’s important to take them to a vet for a physical exam as soon as possible.

How do you go about treating a dehydrated cat?

MD: Dehydration is treated based on its severity and the underlying cause. If a cat is mildly dehydrated and not ill, a vet may use a small needle to administer a bolus of fluids under the skin. This method is called subcutaneous fluids. A cat that receives fluids this way is often sent home. After an hour or two, their body will slowly absorb the fluid. If a cat is severely dehydrated, then hospitalization is often needed to rehydrate a cat more efficiently, which can be done by placing an IV catheter and administering IV fluids. In addition, the cause of the dehydration also needs to be determined and treated.

Can cats recover from dehydration?

MD: It depends on the severity of the dehydration and the underlying cause. If a cat is only mildly dehydrated, then yes, a full recovery is expected. However, if a cat is so severely dehydrated that they’re experiencing multiple organ failure, then recovery is unlikely.

What’s the best way to prevent dehydration in cats?

MD: Make sure your cat’s diet contains moisture. It’s best if your cat’s diet includes canned (wet) food daily. You can either feed canned food only or a combination of dry and canned food. Also, make sure your cat has access to water at all times. Place fresh water in your cat’s water bowl daily and monitor your cat’s water consumption to make sure they drink enough on a daily basis. Adding a cat water fountain in your house can also encourage your cat to drink more frequently.

Is it possible for a cat to drink too much water?

MD: A cat can’t drink too much water. However, increased water consumption is often an indication of a medical condition, such as a urinary tract infection, kidney disease, or diabetes. Alert your local vet as soon as possible if you notice that your cat is suddenly drinking more water than normal.

What should cat owners know about excessive thirst in cats? Why is this something to be concerned about?

MD: Drinking an excessive amount of water can be a sign that your cat has kidney disease, a urinary tract infection, or diabetes. It’s important to bring your cat to your local vet hospital for a physical exam, blood work, and a urinalysis to determine the cause of their excessive thirst.

Kidney disease, a urinary tract infection, or diabetes all require treatment. The sooner a diagnosis is made and treatment is started, the better the prognosis will be. If a urinary tract infection goes undetected for a while, the infection can ascend into the kidneys and cause permanent damage. Kidney disease and diabetes can be life-threatening if diagnosed late in the disease process.

What’s the best way to get a sick cat to drink water?

MD: Offer fresh water and canned (wet) food daily, as canned food contains a higher amount of water than dry food does. If your cat will only eat dry food, you can add some warm water to their kibble to see if they will consume more water this way. A veterinarian may also recommend Purina Pro Hydra Care for your sick cat, which is a liver-flavored liquid supplement that you can offer to your cat in a separate bowl or use as a food topper. This supplement helps to increase water consumption and maintain healthy hydration.

Anything we missed on this topic? What else do you want cat owners to know?

MD: Cats can mask their illness for a while when they’re sick. If you notice a change in your cat’s behavior, eating or drinking habits, energy level, or urinary and fecal output, call your local vet hospital to report your observations. Your vet will help you determine whether you should bring your cat in immediately or if an appointment in a few days is appropriate.