Why Your Dog Is Always Thirsty

Medically Reviewed by Amy Flowers, DVM on March 08, 2024
5 min read

Dogs are messy, hit-and-miss drinkers, so it can sometimes be hard to know just how much water they get in a day.

Most need about an ounce of fluids per pound of body weight per day, so a 10-pound dog needs a bit over a cup of clean water daily. If your dog drinks a lot more than that, it may signal a health problem. Read on to learn more.

Many things can affect how much your dog drinks, from weather to activity level to diet. 

When your dog pants, it loses water through its tongue. So both hot weather and lots of exercise can cause your dog to need more water than usual. Puppies and female dogs who are nursing also need extra hydration. And pups who eat dry food will likely need more water than those on wet food. 

Common sense should be your guide when it comes to whether your dog has excessive thirst. If your canine companion is drinking so much that you're noticing the change, it's probably time to talk to your vet who, with a few tests, can get to the root cause of your dog's increased thirst.

In the meantime, there can be several reasons why your dog is unusually thirsty. 


Hot summer days, play, exercise, illness, infection -- all of these can lead to dehydrationin dogs and trigger them to seek water. Older dogs and dogs that are sick, pregnant, or nursing can get dehydrated easily.

Dog dehydration symptoms. Along with increased thirst, signs that your pet may be dehydrated include:

  • Little energy
  • No interest in eating
  • Sunken eyes
  • Dry mouth
  • Thick, rope-like saliva

You can use these two ways to quickly check your dog for dehydration, too. If the response isn't normal, it's a sign of possible dehydration:

  • Lift the skin on the back between your dog's shoulders. It should sink back to its normal place right away.
  • Gently press on your dog's gums until the pressure creates a light spot. The normal color should come back right away when you remove your finger. Also the gums should feel slick and moist.

Dehydration can turn life-threatening fast, so if you think your dog is very dehydrated, take them to a vet right away. If your dog seems mildly dehydrated but is not vomiting, give your pet small amounts of water -- 1 teaspoon for a little dog, 1-2 tablespoons for larger dogs -- every 10 minutes for a few hours.

Don't let your dog have free access to a lot of liquids when they are dehydrated, as drinking too much too fast could cause vomiting.

Many conditions can lead to excessive thirst or dehydration in your dog, including diabetes, Cushing's disease, cancer, diarrhea, fever, infection, kidney disease, urinary tract infections, and liver disease.

Sometimes, however, it may not be the condition itself causing your dog's excessive thirst, but the medication used to treat it. Talk to a vet about your dog's medication and its side effects; if drugs are behind your dog's thirst, the vet may be able to lower the dosage or find an alternative medication.

Just as with people, some drugs can lead to excessive thirst in your dog, including:

  • Anti-inflammatory drugs like prednisone, which may be used to treat many conditions in dogs, including asthma, allergies, and inflammatory bowel disease.
  • Heart failure drugssuch as furosemide, lead to increased urine production and an increase in thirst.
  • Seizure medications like phenobarbital may have side effects that include excessive thirst and urination.

A dry food diet -- which may be as little as 5%-10% water -- can also lead to noticeable thirst in your dog. High-sodium foods and certain prescription diets will also cause your dog to drink more. 

Large amounts of salt can be poisonous to your pet, so avoid sharing highly salty "people" food with your dog. Signs your dog may have eaten too many sodium-rich treats include tremors, diarrhea, depression, and vomiting.

A good rule of thumb: Make sure your dog gets at least 1 ounce of water daily for each pound they weigh. That means a 20-pound dog needs at least 20 ounces of water every day. That's more than 2 cups, or as much as in some bottles of water or soda.

Leave the water bowl where your dog can get to it easily. Since dogs can knock over the bowl while they're drinking, use one that's made to not tip and spill.

Clean the bowl daily. Refill often so the water supply stays fresh.

Whenever you and your dog are playing outdoors -- especially when it's hot -- bring cool water with you for them to drink. If your dog stays outside on hot days, add ice to the water bowl.

Some dogs are happy to drink from the toilet. But that isn't a clean source of water! Keep the toilet lid closed so your dog stays out.

It's easier to notice changes in your dog's thirst or drinking behavior if you develop a water bowl routine.

  • Refill your dog's bowl at roughly the same time daily.
  • Fill the bowl to about the same level each time.
  • Pay attention to how much you put in each day and how much is left.

Water is critical to your dog's health and well-being. Never deprive your dog of water. If you're worried your dog is drinking too much (or not enough), don't wait: Give your vet a call.