Causes of Excessive Thirst in Dogs

Causes of Excessive Thirst in Dogs
Photo by Elisa Kennemer

Dogs are energetic animals, and this requires them to drink lots of water, making it difficult to gauge how much water they take in a day.

Thirst in dogs can be caused by a number of reasons, from weather to diet to activity levels.

However, excessive thirst in dogs, a condition known as polydipsia, may require medical attention from your vet, who can get to the root cause of your dog’s sudden and increased thirst. 

Meanwhile, here are some of the reasons why your dog may be drinking more water than usual:


Infection, illness, exercise, play, and hot summer days can lead to increased thirst or dehydration in dogs and trigger them to drink more water.

Other symptoms of dehydration along with increased thirst include:

  • Lethargy
  • Dry gums and tongue
  • Thick, rope-like saliva

Dehydration can quickly become fatal. If you notice your dog getting very dehydrated, it is essential that you seek veterinary care immediately.

If the dog is only mildly dehydrated without vomiting, you should give it little amounts of water every ten minutes for a few hours. 

Do not let your dog drink lots of liquids while dehydrated, as drinking too much too fast may lead to vomiting. 

Diabetes Mellitus

Diabetes mellitus is a condition that causes increased sugar levels. It may be due to a deficiency in insulin or insulin resistance. The kidney excretes excess sugar in the blood into urine alongside the water.

Excessive urination in dogs can lead to increased thirst levels. This condition is treated by administering insulin and modifying the dog’s meals. 

Cushing Syndrome

Cushing syndrome occurs when the adrenal gland excretes excessive amounts of cortisol. This can be due to a tumor in the pituitary gland or an adrenal tumor.

Increased levels of cortisol increase thirst, which leads to increased urination.

Cushing’s syndrome is treated using medication or surgery, depending on the location of the tumor.

Kidney Disease

Conditions related to the kidney in dogs may cause them not to be able to concentrate their urine. They pee more and drink more water in order to avoid dehydration.

Kidney disease is treated by adjusting the dog’s food and treating any underlying causes of kidney failure, such as kidney infections or stones.


Pyometra is the medical term for an infected uterus. This condition is specific to female dogs who have not been spayed.

Pyometra is a fatal condition and requires immediate surgical treatment, antibiotics, and rehydration with intravenous fluid therapy.

Vomiting and Diarrhea 

Vomiting and diarrhea may cause dogs to lose body fluids. Dogs who have recently suffered from diarrhea and/or vomiting may drink more than usual to avoid dehydration. 


Some medications can lead to excessive thirst in your pet.

These drugs include;

  • Anti-inflammatory drugs such as prednisone may be used to treat many dogs’ conditions, including allergies, asthma, and inflammatory bowel disease.
  • Drugs that treat heart failuresuch as furosemide, can lead to increased urine production and increased thirst levels.
  • Seizure medications such as phenobarbital may have side effects that include excessive thirst and urination and increased appetite.


A dry food diet that may contain as little as 5%-10% water can also lead to thirst in your dog. Also, foods high in sodium can cause your dog to drink more.

Large amounts of salt can be poisonous to your dog, so avoid sharing highly salty food meant for people with your dog.

Some signs that your dog may have eaten too many sodium-rich treats include tremors, diarrhea, depression, and vomiting.


  • Excessive Thirst in Dogs: Common Causes & When to See the Vet – Hill’s
  • Why Your Dog Is Always Thirsty – Fetch by WebMD
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