Why Is My Dog Drinking So Much Water?

How Much Water Should a Dog Drink?

Figures are based on 40 to 80 mL per kg a day as typical and 100 mL per kg as excessive.^1,2,3 Dogs on canned food drink less, because their food is 60% to over 87% water.⁴ Puppies under about 16 weeks drink more because they can't yet concentrate their urine.³ More than double your own dog's usual amount is also a warning sign, even if it's below these figures.⁵

How to Measure Your Dog's Water Intake

1. Fill the bowl with a measured amount in the morning.
2. Top up with measured amounts through the day, and note each one.
3. After 24 hours, measure what's left and subtract it from the total.
4. If you have more than one pet, measure for one dog at a time if you can.

Repeat for 2 or 3 days and bring the numbers to your vet.^13,5,1 A urine sample collected at home in the morning helps too: concentrated urine makes a real thirst problem unlikely.⁵ Avoid self-filling bowls while you're tracking.³

Why Dogs Drink More Water

Normal reasons

Hot weather, exercise, dry food, and recovering from vomiting or diarrhea.^3,1

Medical causes

• Kidney disease: often the first sign, especially in older dogs. See kidney disease.^7,10,14
• Cushing's disease: usually in dogs about 7 to 12, with a big appetite, potbelly, panting and hair loss. See Cushing's disease.^15,16
• Diabetes mellitus: often with weight loss despite a good appetite. See signs of diabetes.^5,1,12
• Pyometra in unspayed females, usually a few weeks after a heat.⁸
• Steroid medicines such as those used for allergies or inflammation, and some seizure medicines and diuretics.^6,13,2
• High blood calcium, often caused by cancer such as lymphoma or anal sac tumors.¹⁷
• Liver disease, urinary or kidney infections, Addison's disease and some cancers.^1,5
• Diabetes insipidus, a rare condition causing huge amounts of very dilute urine. See diabetes insipidus.^18,19
• Behavioral (psychogenic) drinking, uncommon and mostly in young, active dogs that are bored or left alone. Vets check for other causes first.^20,2,5

A dog that drinks a lot can still become dehydrated, because it's losing water in its urine.^18,10 Extra urine can also make a weak bladder leak. See incontinence in older dogs.²¹

When It's Urgent

A dog that's drinking a lot but otherwise acting normal still needs a vet visit soon, because more drinking and urination can be the first sign of kidney disease or Cushing's.^7,15 Dogs with diabetes insipidus or behavioral drinking are usually bright and alert, while dogs with pyometra or Addison's disease usually seem unwell.²² Go the same day for the warning signs at the top of this page. A dog that drinks but produces little or no urine may have sudden kidney injury or a blockage, which is an emergency.^9,11

Tests Your Vet May Do

• First: urinalysis, blood count and chemistry profile.^1,13,5
• Next, if needed: urine culture, because kidney infections can hide in dilute urine, then hormone tests for Cushing's, calcium and liver tests, and ultrasound.^5,13
• Last: tests for diabetes insipidus or behavioral drinking. A water deprivation test is only done carefully in hospital, never at home.^5,19

Never take away water to test your dog yourself. Restricting water can cause dangerous dehydration.^1,19

Frequently Asked Questions

How much water should a dog drink a day?

About 0.6 to 1.2 ounces per pound of body weight, more in heat or after exercise and less on wet food.

Why is my old dog drinking so much water?

Kidney disease, Cushing's disease and diabetes are the most common causes in older dogs. See your vet for urine and blood tests.

Why is my dog drinking a lot but acting normal?

More drinking can be the first sign of kidney disease or Cushing's, even before a dog seems unwell, so it's still worth a vet visit.

Should I limit my dog's water?

No. Unless your vet says otherwise, your dog likely needs the water.

Can steroids make my dog drink more?

Yes. Increased drinking and urination are very common on steroids. Tell your vet if it's a problem.