Dogs normally take in about 20 to 40 milliliters per pound of body weight per day, or about 3 to 4 cups of water per day for a 20 pound dog. Anything more than that, under normal environmental conditions, is considered polydipsia.

You should watch your dog for increased thirst and urinations. Some dogs may begin drinking from a dripping faucet in the sink or from an open toilet bowl. However, if you want to determine how much your dog is drinking, allow him only one source of water and subtract the amount left in the bowl after 24 hours from the amount you put in originally. If you determine that your pet is drinking excessively, make an appointment with your veterinarian.

The most common causes of polyuria and polydipsia in dogs are chronic kidney failure, hyperadrenocorticism and diabetes mellitus.

Depending on the clinical situation, your veterinarian might recommend additional diagnostic tests to further investigate the cause of polyuria and polydipsia and provide optimal medical care for your pet. Examples of other tests that may be requested include:

Specific diagnostic tests include adrenocorticotropin response test, low- and high-dose dexamethasone suppression tests, urine cortisol-to-creatinine ratio, abdominal ultrasound, and occasionally other specialized tests such as measurement of blood concentration of adrenocroticotropin and elaborate imaging studies such as computerized tomography and magnetic resonance imaging.

Diagnosis is based on finding glucose in the urine in a pet that has a normal blood glucose concentration. This disorder is most likely in certain breeds of dogs such as Basenji dogs and Norwegian elkhounds.

Diagnosis is based on serum biochemistry tests and urinalysis. Treatment is based on rehydrating the pet, trying to slow the progression of the kidney disease by dietary modification, and treating complications such as hypertension and urinary tract infection.

This form of polyuria is transient but the pet must receive adequate fluid therapy to prevent dehydration during recovery.

This diagnosis is based on high blood glucose concentration and the presence of glucose, and often incompletely broken down fat products called ketones in the urine. Treatment depends on severity and may include hospitalization with intensive fluid and electrolyte therapy in conjunction with administration of short-acting insulin or outpatient management with long-acting insulin.

Treatment is based on correcting the underlying cause of potassium depletion. Causes may include: chronic loss of appetite, chronic muscle wasting, vomiting; diarrhea; administration of potassium-deficient fluids; potassium loss through the kidneys; alkalosis (high blood pH); administration of drugs that promote potassium loss; or some combination of these factors. Oral administration of potassium gluconate is the safest method of potassium supplementation.

High blood calcium concentration can be a medical emergency. Hypercalcemia often is a clue to underlying malignancy. Treatment with intravenous fluids, diuretics, and specific drugs may be recommended.

This disorder is a result of the kidney’s inability to respond properly to anti-diuretic hormone, which normally facilitates water reabsorption in the kidney tubules. Usually this disorder is secondary to other problems (e.g. hypokalemia, hypercalcemia), but very rarely it can represent a congenital kidney defect (a problem present at birth). Treatment depends on the initiating cause or symptomatic treatment may be necessary when no underlying disorder can be identified.

This disorder is result of a deficiency of anti-diuretic hormone secretion from the pituitary gland at the base of the brain. It can be “idiopathic” (that is, of unknown cause), due to head trauma or due to a tumor in the pituitary gland. Water deprivation testing and response to anti-diuretic hormone administration confirm the diagnosis. A drug called DDAVP (a synthetic form of anti-diuretic hormone) is administered intra-nasally in drop form to treat central diabetes insipidus.

This disorder is diagnosed by the adrenocorticotropin response tests (failure to respond). Treatment consists of intravenous fluids and replacement of missing steroid hormones.

This disorder can be difficult to diagnose because identification of urinary tract infection by urine culture and sensitivity does not localize the infection to the kidneys. Diagnosis requires integration of complete blood count results, urine culture and sensitivity results, contrast dye study of the kidney (“intravenous pyelogram” or “excretory urogram”), ultrasound of the kidney, and possibly kidney biopsy. Treatment requires long-term administration of antibiotics.

This behavioral disorder is diagnosed on the basis of water deprivation testing after excluding other causes of polyuria and polydipsia. Most veterinarians perform gradual water deprivation to avoid confusion that can arise from loss of normal kidney concentrating ability that can arise simply as a result of longstanding polyuria (“renal medullary washout”). Treatment includes behavioral modification, gradual water restriction and occasionally drugs to counteract obsessive-compulsive behavior.

This cause of polyuria and polydipsia is managed by discontinuing the offending medical treatment.

This disorder is diagnosed based on history (i.e. older intact female dog), complete blood count, and abdominal X-rays or ultrasound. Treatment involves surgery to remove the infected uterus or occasionally prostaglandin type drugs to evacuate the uterus if it is open and draining.

Diagnosed by serum biochemistry tests (including bile acids), abdominal ultrasound, and liver biopsy if necessary.

Definitive therapy of polyuria and polyuria depends on the underlying cause.