Water Intake: The Most Overlooked Part of Pet Nutrition

Water is involved in nearly every bodily process, from regulating temperature to supporting kidney function and digestion, and even mild, sustained under-hydration can place extra strain on the kidneys over time. Unlike a vitamin deficiency that develops slowly, dehydration can become dangerous within a day or two, particularly in small animals, very young or old pets, or anyone already unwell.

Water needs vary with diet, climate, activity and health status, which is why there is no single magic number that applies to every pet; the more useful approach is knowing what normal drinking and urination looks like for your own animal so that changes are noticed early.

Cats descend from a desert-adapted ancestor that obtained most of its moisture from prey rather than from standing water, and this evolutionary history has left many domestic cats with a relatively low thirst drive, especially those fed exclusively dry food. A cat on a dry diet may drink more at the bowl than one on wet food, but the combined water intake from food and bowl drinking is often still lower overall, which may contribute to the prevalence of urinary and kidney issues seen in cats as they age.

Feeding at least some wet food, offering multiple water sources around the home, and keeping bowls away from food and litter trays (since many cats avoid drinking near either) are practical ways to encourage higher overall fluid intake without forcing the issue.

A noticeable, sustained increase in drinking and urination, sometimes described by owners as a pet suddenly seeming to live by the water bowl, is one of the more useful early warning signs in veterinary medicine and can indicate conditions such as diabetes, kidney disease or an overactive thyroid, among others. A decrease in drinking alongside reduced appetite and lethargy can equally signal illness and should not simply be read as the opposite of a problem.

Because 'normal' varies between individuals, the most reliable way to catch a change is to have a rough sense of what is typical for your own pet, rather than comparing against a generic number, and to mention any noticeable shift to a vet even if the pet otherwise seems well.

Cats and dogs both tend to prefer fresh, clean water changed at least daily, and many cats show a strong preference for moving water, which is part of why pet water fountains have become popular, though a simple bowl refreshed regularly works just as well for cats that are not fussy. Placing multiple bowls in different rooms, particularly for multi-pet households or homes with more than one floor, removes the friction of having to travel far to drink.

Ice cubes, a splash of low-sodium broth without onion or garlic, or wetting dry kibble slightly can all increase intake for a reluctant drinker, though a pet that has stopped drinking altogether, is drinking far less than usual, or shows signs of dehydration (tacky gums, skin that stays tented when gently lifted, lethargy) needs veterinary assessment rather than home remedies.

Hot weather, increased exercise, lactation, fever, vomiting, diarrhoea and some medications all increase a pet's water requirements, sometimes substantially, and owners should offer more access to water proactively during these periods rather than waiting for obvious thirst behaviour. Pets recovering from illness or surgery, or those on prescription diets for kidney or urinary conditions, may have specific hydration guidance from their vet that is worth following closely, since fluid intake is often part of the management plan for those conditions rather than an incidental detail.