Is My Dog Dehydrated?

Michelle Diener, DVM
By Michelle Diener, DVM on Feb. 4, 2022

Water is a vital nutrient for dogs, just like it is for people. Dogs need to drink water daily because it helps regulate their body temperature, support organ function, lubricate their joints, and aid in digestion. Without water, a dog will become severely dehydrated and pass away if not treated in time.

That’s why it’s so important to recognize the signs of dehydration in dogs so you can get them the proper treatment. Here’s what you need to know.

What Is Dehydration in Dogs?

Dehydration occurs when a dog loses more fluid than they are consuming. Water can be lost through panting, breathing, urination, defecation, vomiting, and even evaporation through the paw pads.

As a dog becomes dehydrated, they start to lose their ability to regulate their body temperature.

Dehydration also causes abnormalities in electrolytes. Dogs that suffer from dehydration often have low sodium, chloride, and potassium. These electrolytes are important for allowing transport of nutrients into cells throughout the body. They also aid in muscle function and nerve activity.

Why Is Dehydration in Dogs a Serious Issue?

Dehydration in dogs needs to be taken seriously. If your dog shows any signs of dehydration, offer them a small amount of water and immediately call your local or ER vet hospital.

Severe dehydration can be life-threatening because it can cause the organs, such as the heart, liver, and kidneys, to shut down due to decreased cardiac output and poor blood circulation throughout the body.

Puppies are more susceptible to dehydration due to their small body mass. They have a lot of energy and need plenty of water to stay hydrated throughout the day.

Signs of Dehydration in Dogs and Puppies

Here are some quick tests you can do at home and things you can check for to see if your dog might be dehydrated.

Skin Pinch Test (Skin Tent)

You can check for dehydration by testing the elasticity of your dog’s skin. Do this by gently pulling up some of your dog’s loose skin at the back of their neck or over the shoulder blades, and then releasing it.

In well-hydrated dogs, the loose skin should instantly spring back to its original position. The skin of dehydrated dogs will take longer to fall back into place and will have the appearance of being tented above the neck or shoulders. This is referred to as a skin tent.

Tacky, Dull Gums

If your dog will allow you to look in their mouth, check their gums. In a well-hydrated dog, they should be pink, glisten, and appear moist. Touch the gums. If your finger sticks to them, then the gums are said to be tacky. This is a sign of dehydration. 

Dry Nose

A dog’s nose should be moist. If your dog’s nose is dry, this can be an indication of dehydration or another medical issue, like a skin infection.

Thick, Stringy Saliva

Normal saliva from a dog’s mouth should be thin and watery. When a dog is dehydrated, their saliva is usually thick and ropey and clings to their mouth.

Sunken Eyes

This is often a sign of severe dehydration, which occurs when the amount of fluid in the fat pads behind the eyes is diminished and causes the eyes to sink into the eye sockets.

Decreased Energy Level (Lethargy)

Dogs that are dehydrated become weak and tend to lie around. They are not interested in playing, running, or jumping. Instead, they try to conserve their energy to prevent their dehydration from getting worse.

Excessive Panting

Dogs commonly pant to cool themselves down. If your dog is panting more than normal, this can be a sign of dehydration, but can also indicate pain, anxiety, or a chronic medical condition called Cushing's disease. Alert your local vet if your dog’s panting has increased.

What to Do If Your Dog Is Dehydrated

If you suspect your dog is only mildly dehydrated because they have tacky gums but no other symptoms (no lethargy, vomiting, diarrhea, or decreased appetite), then offer them a small amount of cool water to drink. Do not give a large volume of water at once, as your dog may drink it too quickly and vomit.

For a small dog, give 1 teaspoon of water every few hours. For medium to large breed dogs, offer 1 tablespoon to a 1/4 cup every few hours.   

If your dog appears moderately or severely dehydrated and has other symptoms, like lethargy, decreased or increased urination, vomiting, or diarrhea, or they have not eaten in 24 hours, call your local vet or ER vet hospital immediately.

Provide any important information, such as if your dog was outside in the heat for a certain amount of time or if your dog has any symptoms (specify what symptoms and how often they have been occurring). 

Causes of Dehydration in Dogs of All Ages

There are many causes of dehydration in dogs of all ages. Here are some of the most common.


This is when a dog’s body temperature rises above 105.8℉arenheit (41℃elsius) due to severe heat exposure. This could be caused by being trapped in an enclosed vehicle, strenuous exercise, or non-stop seizure activity.

Never leave your dog (or any pet) in an enclosed vehicle, even when the temperature is 60℉ outside. Dogs can still develop heatstroke within 15-20 minutes in an enclosed vehicle with this type of weather, even if the windows are cracked.

Dogs are more prone to heatstroke if they are overweight or brachycephalic (short-muzzled/flat-faced) breeds, but all dogs are at risk. It is best to leave your dog at home if you are not able to run the air conditioning in your car and provide access to water, even if you are running a quick errand. 

Persistent Vomiting and/or Diarrhea

When a dog has ongoing vomiting and/or diarrhea for various reasons, they are constantly losing fluids within the vomit or diarrhea.

Any dog that has had ongoing vomiting and/or diarrhea for 24 hours or more needs to be taken to a vet hospital immediately.

Dogs that are losing bodily fluids through vomiting and diarrhea are not able to drink enough water to replace their fluid loss, and they will develop severe dehydration if not treated quickly.

Not Getting Enough Water

If a dog is not provided enough water to maintain their daily water requirement, they will get dehydrated. Check your dog’s water bowls daily both inside and outside the house to make sure they are filled with fresh, clean water. 

Chronic Illness

Dogs that have kidney disease, Cushing's disease, or diabetes tend to be dehydrated and often drink more water than normal. Even with an increase in water consumption, dogs with these chronic illnesses are usually still dehydrated.

Make sure water is readily available for your dog to drink. It is beneficial to feed your dog canned food, as this helps increase the amount of fluids your dog is consuming.

If your dog is suddenly drinking and urinating more than normal or having urinary accidents in the house, schedule an appointment with your veterinarian to determine the underlying cause of these symptoms.

Causes of Dehydration In Puppies

In addition to the previous causes, these are some common causes of dehydration in puppies.


Parvovirus is a highly contagious intestinal virus that often causes lethargy, decreased appetite, and severe bloody vomiting and diarrhea.

Puppies with parvovirus are commonly dehydrated due to the constant vomiting and diarrhea that this virus causes. To protect your puppy from parvo, get them vaccinated against this virus and keep them away from public areas until they are fully vaccinated.

Intestinal Parasites (Worms)

Puppies are more often diagnosed with intestinal parasites compared to adult dogs. This is because puppies tend to acquire the most common parasites (hookworms and roundworms) through their mother’s milk when nursing.

They are also more prone to picking up parasites in the environment before they are old enough to start taking heartworm prevention, which protects against intestinal parasites.

Puppies also have weaker immune systems and typically show symptoms of parasites faster than adult dogs. However, dogs of all ages are prone to intestinal parasites. The most common intestinal parasites are hookworms, roundworms, whipworms, tapeworms, Giardia, and coccidia.

If you have a puppy or an adult dog that is vomiting or has diarrhea and they are not on heartworm prevention, have your dog’s stool checked at a veterinary hospital for intestinal parasites. Most parasites cannot be seen in the stool or the vomit with the naked eye. Your vet will be able to find the eggs of intestinal parasites in the stool by using a microscope.

Foreign Body Obstruction (Eating Rocks, Toys, Etc.)

Puppies are very curious about everything. They do not instinctively know what they should and should not eat. Puppies and even some adult dogs are prone to eating things like rocks, carpet, socks, etc.

When a dog consumes a foreign object, it tries to pass through the gastrointestinal tract but has a tendency to get stuck. If the foreign object becomes lodged in the gastrointestinal tract, it will prevent food or water from passing, as well. This is called a gastrointestinal obstruction.

Vomiting up food and water within 30 minutes of eating or drinking is common when a dog has an obstruction. This can quickly lead to severe dehydration. If your dog cannot hold food or water down, or you see your dog eating something they shouldn’t, immediately call your local or ER veterinarian.

Treatment for Dehydration in Dogs

Most dogs that are dehydrated need medical attention. The cause of the dehydration needs to be determined with a thorough medical history, physical exam (checking body temperature, heart rate, and respiratory rate), and diagnostic tests (intestinal parasite check, abdominal x-rays, urinalysis and/or routine bloodwork). 

These tests will check for heatstroke, causes for vomiting/diarrhea, and chronic illnesses such as kidney disease and diabetes.

Veterinarians will treat a dog’s dehydration by giving subcutaneous fluids (fluids that go under the skin) or intravenous fluids (fluids that are given into the vein through an IV catheter).

These fluids will replace fluids that were lost and also treat any electrolyte imbalance. The severity and cause of the dehydration determines which fluid-replacement method will be best to achieve rehydration. The veterinarian must also treat the underlying cause of the dehydration.

How to Keep Your Dog From Getting Dehydrated

Here are some tips for making sure your dog stays well-hydrated.

Always have enough clean water available.

It is super important to keep your dog’s water bowl filled throughout the day with fresh, clean water. Monitor your dog’s water consumption daily to make sure your dog is drinking a normal amount of water. 

On average, a dog should drink 1 ounce of water per pound of body weight per day. This would equate to 3 cups of water daily for a 25-pound dog. You can use this calculation to get a rough estimate of how much water your dog should normally drink per day based on their body weight.

Provide more water when your dog is exercising or if they are outside in hot or humid weather.

Limit your dog’s time outdoors when it’s hot or humid outside. Do not leave your dog in your car when running errands. It is best to keep your dog in an air-conditioned environment away from the heat to avoid possible heatstroke.

Stay up-to-date on shots and parasite prevention.

Keep your dog up-to-date on vaccines and heartworm and flea/tick prevention to minimize the risk of infectious diseases and parasites.

Watch what your dog eats.

Prevent your dog from eating things they should not eat (fatty food made for humans, objects in the house or outside, table scraps, garbage, toxic substances).

Take your dog for regular checkups.

Have bloodwork and a urinalysis performed once a year on your dog as a screening test to check for kidney disease, diabetes, pancreatitis, and other illnesses that can lead to dehydration. For senior dogs, it’s best to take them every 6 months.

Featured image:


1. James L. Cook1 DVM, Steven P. Arnoczky2 DVM. World Small Animal Veterinary Association World Congress Proceedings, 2013. VINcom. Published online March 30, 2015. Accessed February 4, 2022.

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Michelle Diener, DVM


Michelle Diener, DVM


I live in Raleigh, North Carolina. I obtained by BS degree in Biology at UNC-Chapel Hill in 2000 and my DVM degree at NCSU in 2006. I have...

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