Why Is My Cat Drinking a Lot of Water? Is This Normal?

A cat drinking a lot of water can have many causes, from normal changes in diet or environment to underlying medical conditions or medication side effects. 

A cat’s diet can play a major factor in how much water they drink. Because wet food is 70%–80% water, a cat on wet food is getting most of their hydration from their meal, whereas a cat on dry food might noticeably drink more water, says Feargus McConnell, BVSc, a veterinarian in Denver, Colorado. 

This is to be expected—and isn’t a concern unless it becomes excessive—because their water intake has to come from somewhere on a dry diet, he notes. 

Another common reason why a cat might drink more water than usual is dehydration. There are several causes for dehydration in cats, such as: 

• Vomiting or diarrhea 
• Not drinking enough water 
• Hot weather 
• Stress 

Changes in your cat’s environment can also affect how much they drink, says Michelle Bernstein, ACAAB, MA, MS, an animal behaviorist and veterinary professional in Las Vegas, Nevada.   

Hot weather, extra activity, stress, moving the water bowl, or introducing a new pet or water fountain may all temporarily increase water intake, adds Maggie Placer, DVM, a veterinarian and the veterinary sciences program manager of EveryCat Health Foundation in Lafayette, Louisiana.  

These changes are often short-lived, but if your cat continues drinking much more than usual, it’s worth checking in with your veterinarian. 

Consistently drinking water can also be a sign of diabetes in cats, according to our experts. A fairly common chronic condition in felines, diabetes causes a cat’s blood sugar levels to rise, leading to increased thirst. 

One of the most common health issues in senior cats is kidney disease. This disease impacts the kidneys’ ability to concentrate urine properly. As a result, a cat’s urine is typically diluted and they constantly drink water to keep up, Dr. McConnell says. 

Excessive thirst can also be a symptom of hyperthyroidism in cats. With this condition, a tiny, benign tumor on the thyroid gland causes the thyroid to go  “into overdrive,” speeding up the metabolism, Dr. McConnell explains. 

Medications containing glucocorticoid steroids—such as prednisolone, methylprednisolone, and dexamethasone—may cause excessive thirst and increased urination, Dr. McConnell says. It’s recommended to report these side effects because it’s crucial information for your cat’s treatment plan. 

A noticeable or persistent increase in thirst is always worth paying attention to, says Timothy Hunt, DVM, veterinarian and founder at Bayshore Veterinary Hospital in Marquette, Michigan. 

It doesn’t necessarily mean something is wrong, but because excessive thirst can be an early sign of illness, it’s a good idea to let your veterinarian know.  

Contact your veterinarian sooner if your cat is also experiencing: 

• Weight loss 
• Increased urination 
• Vomiting 
• Lethargy 

If your cat starts drinking more water than usual, don’t take the bowl away. Instead, keep fresh water available and pay attention to what’s changed.   

These steps can help you gather information before you talk with your veterinarian: 

• Don’t restrict your cat’s water. Always keep fresh, clean water available.  

• Measure how much they’re drinking. Fill your cat’s water bowl with a measured amount of water, then check how much is left after 24 hours.  

• Watch for other changes. Make note of your cat’s appetite, litter box habits, energy level, and anything else that’s out of the ordinary.  
• Contact your veterinarian. Let them know about any changes in your cat’s drinking habits so they can recommend next steps.  
• Seek veterinary care right away if your cat is also vomiting, eating less than usual, straining in the litter box, or showing other signs of illness.  
• If your veterinarian rules out a medical cause, consider consulting a certified cat behavior expert.  

To determine what’s causing excessive thirst, your veterinarian may review your cat’s diet, medications, weight, and other symptoms, then recommend blood work and a urinalysis to evaluate kidney function, blood sugar, and urine concentration, Dr. Hunt says. 

Because kidney disease is common in older cats, your veterinarian may recommend routine blood work and SDMA testing beginning around age 7 to establish a baseline and detect changes early. 

Cats should drink roughly 50 milliliters per kilogram per day from all sources, including food, according to Dr. McConnell. For reference, a healthy 10-pound cat typically gets about 8 ounces of water each day from both food and drinking. 

Cats are good at masking illness and pain, meaning they may feel bad internally before showing outward signs, Dr. Placer says. Sometimes, the signs of something underlying can first show itself through a change in water intake habits; it’s always a good idea to consult your vet if you notice any changes. 

Excessive thirst in cats looks like emptying their water bowls faster than usual and urinating more frequently. 

You should take your cat to the vet for drinking too much water when you notice increased thirst, as well as weight loss, increased urination, vomiting, or lethargy, Dr. Hunt says.