By Dr. Tracy Dewhirst
It’s astute of you to notice your dog’s unusual thirst, because many owners aren’t aware how much water their dogs normally drink. Most dog owners refill the water bowl often, keeping the water cool and fresh, but are unaware that their dog is drinking more.
If you find yourself filling the water bowl more than usual, even if your dog is otherwise healthy, it’s an early red flag that something could be wrong. Excessive drinking is called polydipsia, and because what goes in must come out, it often correlates with polyuria, or excessive urination.
There are times when we all need a little more to drink, such as on a hot summer day or when we are exercising or stressed, but otherwise an increased thirst is abnormal. Some dogs that are polydipsic will seek water in random places, such as the shower stall after you exit, the toilet, small puddles of water after a rain or even condensation on a cold surface.
Polydipsia is a telltale sign of certain diseases, such as diabetes, Cushing’s disease (excessive natural steroid production), Addison’s (low steroid production), kidney disease, liver disease, some cardiac problems, partial obstructions of the urinary tract, uterine infections, hyperthyroidism, infectious leptospirosis and cancer.
Occasionally, polydipsia can be a behavioral problem – psychogenic -- but medical causes must be ruled out first. Also, some medications can increase thirst. If your dog is polydipsic, your veterinarian will need to do blood and urine tests and perhaps more specialized testing and imaging, depending on the cause.
Water consumption is such a natural part of life for a dog that we rarely consider it, and we certainly don’t measure it. But if you suspect your dog is drinking more than normal, you can track his intake. If your dog drinks more than 100 milliliters per kilogram of his body weight per day, he’d be considered polydipsic. Divide your dog’s weight in pounds by 2.2 to get his weight in kilograms.
For example, a 25-pound dog: