Why is my dog drinking so much water ?


How much water should my dog drink?

normal water intake as 1-2ml per kilogram of bodyweight per hour (equivalent to approximately 25-50ml/kg/24hrs).

For example, a 10kg dog, like a Westie, would be expected to drink approximately 480ml (just under a pint) in 24 hours. Marked variation can be seen between individuals, dependent on the amount of water taken in with their food (wet vs dry food), and water lost through exercise.

What is Polydipsia?

Polydipsia (increased drinking) is defined as more than 100ml per kg per day. Still drinking less than this amount. More than 50ml/kg/24hrs may raise suspicion about polydipsia, whereas over 100ml/kg/24hrs is definitely polydipsia. Polyuria refers to an abnormally high urine production. 

Why is my dog drinking so much water?

Water balance is tightly controlled by the body through regulation of water intake and water loss in the urine. Lack of water intake or excessive water loss causes the pituitary gland in the brain to release “anti-diuretic hormone” signals the kidneys to conserve water and to concentrate the urine.

In these circumstances, the thirst center in the brain is also triggered to stimulate drinking. Increased drinking can occur either because the concentrating mechanisms of the kidneys fail, the kidneys do not respond to ADH, ADH is not produced or released, or because there is an excessive stimulus to drinking (polydipsia ).  

The causes of an increase in the consumption of water in your pet can be varied. The kind of causes we see are:
  • Kidney (renal) dysfunction
  • Liver (hepatic) disease
  • Diabetes mellitus (“sugar diabetes”)
  • Diabetes insipidus (“water diabetes”)
  • Hyperthyroidism (over active thyroid) in cats
  • Pyometra, an infection of the uterus (“womb”) in unstayed animals
  • Cushing’s disease, an overproduction of natural steroid, cortisol, by the adrenal glands
  • Addison’s disease, reduced steroid production by the adrenal glands
  • Urinary tract infections
  • High calcium levels, sometimes associated with cancer
  • Behavioral issues as pets become psychologically obsessed with drinking excessive amounts of water (psychogenic polydipsia)
  • Compensatory polydipsia losses after vomiting or diarrhea

If you are worried about your pet’s fluid intake – it can be helpful to measure their water intake over a 24 hour period and pass this information on to your vet, along with a fresh urine sample, ideally collected first thing in the morning.

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