Dog Drinking a Lot of Water

This guide is for informational purposes and does not replace veterinary advice.

Normal Water Intake for Dogs

Understanding what “normal” looks like is the first step in recognizing excessive drinking. Dogs need approximately 1 fluid ounce (30 ml) of water per pound of body weight per day under normal conditions. This means:

• A 10-pound dog: ~10 oz (1.25 cups) per day
• A 25-pound dog: ~25 oz (~3 cups) per day
• A 50-pound dog: ~50 oz (~6 cups) per day
• A 100-pound dog: ~100 oz (~12 cups) per day

Water needs increase with exercise, heat, dry food diet, nursing puppies, and certain medications. However, if your dog is drinking more than 2–2.5x their normal amount without an obvious explanation (like hot weather or extra exercise), this is called polydipsia and warrants investigation.

Causes of Excessive Thirst in Dogs

Source: Merck Veterinary Manual; American Animal Hospital Association guidelines

Medical Conditions That Cause Excessive Thirst

Diabetes Mellitus

Canine diabetes affects the body’s ability to regulate blood sugar. When blood glucose rises excessively, the kidneys cannot reabsorb all the glucose, drawing water with it and creating frequent, large-volume urination — which then drives excessive thirst. Signs include dramatic increases in both drinking and urination, weight loss despite normal or increased appetite, and lethargy. Management involves insulin therapy and dietary changes.

Kidney Disease (Chronic Kidney Disease)

The kidneys regulate water balance in the body. When kidney function declines, the kidneys may lose their ability to concentrate urine, leading to large-volume dilute urination and compensatory increased drinking. CKD is especially common in older dogs. Regular blood and urine tests can detect kidney disease early — see our guide on finding veterinary clinics for annual wellness testing.

Cushing’s Disease (Hyperadrenocorticism)

Cushing’s disease occurs when the adrenal glands produce excess cortisol. This directly increases thirst and urination, along with causing a pot-bellied appearance, muscle weakness, hair loss, and increased appetite. It primarily affects middle-aged to senior dogs and requires specific diagnostic testing and treatment.

Urinary Tract Infections

UTIs cause inflammation and irritation in the bladder, leading dogs to drink more and urinate more frequently, often in small amounts. Dogs with UTIs may strain to urinate, pass blood-tinged urine, or urinate in inappropriate places. UTIs are treatable with antibiotics but require veterinary diagnosis and urinalysis.

Diagnosis & Treatment

If your dog is drinking excessively, your veterinarian will typically:

• Complete blood count (CBC) and chemistry panel — screens for kidney, liver, and blood disorders
• Urinalysis — checks urine concentration, glucose, protein, and signs of infection
• Urine culture — if UTI is suspected
• ACTH stimulation test or low-dose dexamethasone suppression test — if Cushing’s is suspected
• Abdominal ultrasound — to examine kidneys, adrenal glands, and other organs

Treatment depends entirely on the underlying cause — from antibiotics for UTIs to insulin therapy for diabetes, Trilostane for Cushing’s disease, or supportive care for kidney disease.

How to Monitor Your Dog’s Water Intake

If you suspect your dog is drinking too much, measure their daily water intake for 2–3 days before your vet visit:

• Fill a measured container each morning
• Track how much remains at the end of each day
• Account for any water used in cooking food or added broth
• Compare to the normal guideline (1 oz per pound per day)
• Note whether urination volume and frequency has also increased

This information will help your veterinarian significantly in making a diagnosis. Also track when the excessive drinking started and any other behavioral or physical changes you’ve noticed.

Frequently Asked Questions