If your dog is drinking water excessively, it may be more than just thirst—it could be a sign of an underlying health issue.
While dogs naturally drink more after play, heat, or salty food, ongoing excessive thirst is not something to ignore.
We outline the common causes of dog drinking water excessively, what you can do at home, and when to seek veterinary help.
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Dog Drinking Water Excessively — Why It Happens
Excessive water consumption in dogs, known as polydipsia, can be caused by dehydration, kidney disease, diabetes, Cushing’s disease, or certain medications.
While occasional increased thirst can be normal, consistent and abnormal water intake—especially paired with other symptoms—may point to something more serious.
Common Causes of Dog Drinking Water Excessively
Dehydration
After exercise, hot weather, or bouts of diarrhea or vomiting, dogs may drink more to restore fluid balance.
You may notice sunken eyes, dry gums, or skin that doesn’t bounce back when pinched.
Mild dehydration often resolves with rest and access to clean water, but severe cases may require fluids from a vet.
Kidney Disease
The kidneys regulate fluid and waste. When they’re not working well, your dog may drink and urinate more frequently.
Other signs include weight loss, bad breath, pale gums, and a dull coat. It’s more common in older dogs.
Routine bloodwork and urinalysis can detect early kidney issues.
Related: Dog drinking a lot of water and not eating (Here’s why)
Diabetes Mellitus
Excess sugar in the blood causes the body to pull water from tissues, leading to increased thirst and urination.
You might also notice weight loss despite a good appetite, lethargy, or cloudy eyes.
Diabetes is treatable with insulin and diet management, but early detection is key.
Cushing’s Disease
This hormonal condition causes the body to produce too much cortisol, leading to excessive drinking and urination.
Other signs include a pot-bellied appearance, hair loss, and increased appetite.
Cushing’s is common in middle-aged and older dogs and requires blood tests for diagnosis.
Medications (Steroids or Diuretics)
Drugs like prednisone or diuretics can make your dog thirstier as a side effect.
If the excessive drinking started after starting a new medication, ask your vet if it’s expected or requires adjustment.
Never stop medications without veterinary guidance.
Liver Disease
The liver plays a role in metabolism and detoxification. When it’s compromised, thirst may increase.
Other symptoms can include vomiting, jaundice (yellowing of skin or eyes), and behavior changes.
Blood tests and imaging help identify liver problems and determine treatment.
What to Do If Your Dog Is Drinking Water Excessively
Track how much your dog is drinking each day. Normal intake is about one ounce per pound of body weight daily. Mark your bowl or use a measuring cup to monitor changes.
Provide fresh water, but avoid encouraging over-drinking just to check.
Note any additional symptoms like changes in appetite, urination, weight, or energy.
Consider recent lifestyle changes—new foods, increased activity, medications, or weather—that could affect thirst.
Avoid restricting water unless advised by your vet, as this can cause further complications.
When to Call or Visit Your Vet
Contact your vet if your dog:
Drinks far more than usual for multiple days
Needs to urinate more frequently or has accidents
Shows signs of weight loss, vomiting, or lethargy
Is a senior or already has a chronic condition
Starts drinking more after a new medication
Excessive thirst often signals a problem with internal balance. Your vet may perform bloodwork, urinalysis, or imaging to find the root cause.
Related:
Read more: Dog Panting Excessively (Explained)
Read more: Dog Eating Grass Excessively (What it means)
Key Takeaway
If your dog is drinking water excessively, it’s important to take notice. While thirst can be normal after heat or play, ongoing excessive water intake may signal an issue like diabetes, kidney disease, or medication side effects.
Monitor closely, avoid restricting water, and consult your vet for a diagnosis. Early action can prevent more serious problems and support your dog’s long-term health.