Dog Drinking Excessive Water — Causes and When to Worry

If you've noticed your dog drinking much more water than usual, you're right to be concerned. Excessive thirst (polydipsia) can be an early sign of serious health conditions that require prompt veterinary attention.

How Much Water Is Normal?

Healthy dogs typically drink 0.5 to 1 ounce of water per pound of body weight daily. This means:

• 20-pound dog: 10-20 ounces (1.25-2.5 cups)

• 40-pound dog: 20-40 ounces (2.5-5 cups)

• 60-pound dog: 30-60 ounces (3.75-7.5 cups)

• 80-pound dog: 40-80 ounces (5-10 cups)

Water needs increase with exercise, hot weather, dry food diets, and certain medications. However, sudden changes in drinking habits warrant veterinary evaluation.

Common Causes of Excessive Thirst

Medical Conditions

Diabetes: High blood sugar causes excessive urination, leading to increased thirst to replace lost fluids. Blood tests can detect elevated glucose levels.

Kidney Disease: Failing kidneys can't concentrate urine effectively, causing increased water loss and compensatory drinking.

Cushing's Disease: Excess cortisol affects kidney function and creates hormonal imbalances that increase thirst.

Liver Disease: Liver problems can disrupt fluid balance and create toxin buildup that triggers thirst.

Hyperthyroidism: Overactive thyroid (rare in dogs) increases metabolism and water needs.

Medications

Steroids: Prednisone and other corticosteroids commonly increase thirst and urination.

Diuretics: "Water pills" increase urine production, requiring more water intake.

Seizure Medications: Some anti-seizure drugs can affect thirst regulation.

Infections and Other Causes

Urinary Tract Infections: UTIs can increase urination frequency and compensatory drinking.

Pyometra: Uterine infection in unspayed females causes increased thirst and other serious symptoms.

Cancer: Some tumors affect hormone production or kidney function.

Warning Signs to Watch For

Contact your veterinarian if your dog shows:

• Sudden, significant increase in water consumption

• Drinking more than 1.5 ounces per pound of body weight daily

• Excessive urination (especially accidents in house-trained dogs)

• Loss of appetite or weight loss

• Lethargy or behavioral changes

• Vomiting or diarrhea

• Sweet-smelling breath (possible diabetes)

Diagnostic Tests Your Vet May Recommend

Blood tests are essential for diagnosing the cause of excessive thirst. Learn how to understand your dog's results with our comprehensive guide to reading dog blood test results. Understanding these tests helps you make informed decisions about your dog's care.

Blood Chemistry Panel

Glucose: Checks for diabetes (normal range 74-143 mg/dL)

BUN and Creatinine: Kidney function markers that indicate how well kidneys are filtering waste

Liver Enzymes (ALT, ALP): Elevated liver values may indicate liver disease affecting fluid balance

Electrolytes: Sodium, potassium, and chloride levels show hydration status and kidney function

Complete Blood Count (CBC)

CBC results can reveal infections, anemia, or other blood abnormalities that might contribute to increased thirst.

Urinalysis

Specific Gravity: Shows how well kidneys concentrate urine

Glucose in Urine: May indicate diabetes

Protein Levels: Can signal kidney disease

Additional Tests

Thyroid Hormone (T4): Screens for hyperthyroidism

Cortisol Tests: ACTH stimulation or low-dose dexamethasone suppression test for Cushing's disease

Water Deprivation Test: Sometimes used to differentiate between causes of excessive urination

For cost planning, check our dog bloodwork pricing guide to understand typical expenses for these diagnostic tests.

Treatment Options

Treatment depends on the underlying cause:

Diabetes: Insulin therapy, dietary management, and regular blood sugar monitoring

Kidney Disease: Special diet, medications to support kidney function, fluid therapy

Cushing's Disease: Medications to control cortisol levels or surgery in some cases

Infections: Appropriate antibiotics or antifungal medications

Medication-Related: Adjusting dosages or switching medications when possible

Monitoring at Home

To track your dog's water consumption:

• Measure water in the bowl each morning and evening

• Note any changes in urination frequency or volume

• Keep a log of daily water intake for veterinary visits

• Watch for other symptoms like appetite changes or lethargy

• Take photos of urine color and consistency if abnormal

When It's an Emergency

Seek immediate veterinary care if your dog shows:

• Severe lethargy or collapse

• Repeated vomiting or inability to keep water down

• Signs of dehydration despite excessive drinking

• Sweet-smelling breath with excessive panting

• Complete loss of appetite for more than 24 hours

Related Reading

• How to Read Dog Blood Test Results – understanding diagnostic bloodwork

• Dog Bloodwork Cost Guide – pricing for diagnostic testing

• Chronic Kidney Disease in Cats – kidney disease information for cat owners

Frequently Asked Questions