Why Is My Dog Drinking A Lot Of Water?

Your pup's excessive thirst might require a trip to the vet.

dog drinking from water bowl

It’s not unusual for your pup to guzzle down a whole bowl of water when you come in from the hot sun.

But if your dog’s drinking like he’s never seen water before or there doesn’t seem to be a cause for his thirst, it can be a sign that he’s sick. So what should you do if your dog’s excessive drinking seems abnormal?

We reached out to Dr. Alex Schechter, a veterinarian and founder of Burrwood Veterinary Hospital in Detroit, to find out why your dog’s drinking a lot of water and how to know if it’s a problem.

Reasons for your dog drinking a lot of water

There are a number of reasons why your pup’s drinking a lot of water, and not all of them are cause for concern.

It’s normal for your dog to drink a lot of water when he gets inside on a hot day or after a long walk. Some medications, such as steroids, and food can cause excessive thirst and urination in dogs.

But sometimes, excessive drinking can be a sign of certain illnesses.

“Some illnesses, such as diabetes, Cushing's disease, chronic kidney disease, cancer, fever, infection and liver disease, also cause excessive thirst and urination in canines,” Dr. Schecter told The Dodo.

If your dog suddenly started drinking a lot more than usual with no obvious cause (like hot weather), or if he has other symptoms of illness, you should take him to the vet to get him checked out.

“If your pet is constantly drinking water from the bowl and hitting the toilets for more than a few days, you should immediately book an appointment with your vet,” Dr. Schechter said.

These are some common causes of excessive thirst in dogs and their symptoms.


When a dog has diabetes, his body doesn’t produce enough insulin or doesn’t process the insulin correctly, which can lead to high blood sugar. If a dog’s blood sugar gets too high, the glucose gets passed into his urine with extra water (since glucose attracts water). This causes excessive drinking and urination in pups with diabetes.

Cushing’s disease

Cushing’s disease, or Cushing’s syndrome, is a condition where a dog’s body doesn’t produce the right amount of cortisol. The most common signs of Cushing’s disease are increased urination and drinking.

Kidney or liver disease

Along with drinking and peeing a lot, other symptoms of kidney or liver disease include weight loss, muscle loss, lack of appetite, nausea, anemia, neurological issues, weakness, fluid in the belly, confusion and jaundice.


Vomiting, diarrhea, heatstroke, fever and not drinking enough water can cause your pup to become dehydrated. Symptoms of dehydration in dogs include dry nose, drooling, lethargy and sticky gums.


Hyperthyroidism is pretty rare in dogs. It’s a condition that occurs when the thyroid glands produce more hormones than necessary. Thyroid hormones help control a dog’s metabolism, so dogs with hyperthyroidism will have a faster metabolism than normal.

If your pup has this disease, he might lose weight with no apparent cause. Other signs include vomiting, diarrhea, increased appetite, rapid breathing and heart rate, heart murmur, difficulty breathing, hyperactivity, and swollen thyroid glands (in the neck).


Dogs who eat dry food can sometimes drink a lot of water, since it has a lower water content than wet food. Foods that are high in salt will make your pup thirsty, too.

Can dogs ever drink too much water?

It’s possible for your dog to drink too much water, and while that may sound like a good thing, it’s actually dangerous.

“Excessive water drinking can lead to water intoxication, which can be life-threatening for your pet,” Dr. Schechter said. “When water intoxication occurs, you may witness lethargy, bloating, vomiting, stumbling, falling, staggering, restlessness, dilated pupils or glazed eyes, etc., in your pet.”

It can be helpful to use a measuring cup for your dog’s water so you’ll know exactly how much water he’s drinking.

“To [keep track of] your pet's drinking behaviors, keep an eye on its water bowl,” Dr. Schechter said. “Refill the bowl daily with the same water level, and monitor how much the pet is drinking every day.”

While it’s important to make sure your pup stays hydrated, you should also keep an eye on his drinking habits so you can tell when he’s drinking a little too much.

We independently pick all the products we recommend because we love them and think you will too. If you buy a product from a link on our site, we may earn a commission.