Cats evolved as desert animals, and they've retained the ability to concentrate their urine and survive on less water than many other mammals. But in domestic life, this adaptation often leads to chronic mild dehydration — with serious health consequences.
Why Hydration Matters
Chronic dehydration is a significant risk factor for two of the most common feline health problems: urinary tract disease and chronic kidney disease (CKD). CKD affects approximately 30–40% of cats over the age of 10, according to the International Renal Interest Society (IRIS). While the causes of CKD are multifactorial, maintaining good hydration helps support kidney function and can slow disease progression in affected cats.
How Much Water Do Cats Need?
Cats need approximately 50 ml of water per kilogram of body weight per day (roughly 1 ounce per pound). A 4 kg (9 lb) cat needs about 200 ml (7 oz) daily. However, cats on wet food diets get a significant portion of their water from food — canned food is about 75–80% water, while dry food contains only 6–10%. A cat eating exclusively dry food needs to drink significantly more water to compensate.
Why Cats Don't Drink Enough
Cats' desert ancestry means they have a low thirst drive compared to dogs. They often don't feel compelled to drink until they're already slightly dehydrated. Additionally, cats are particular about water quality and presentation. Studies have shown that cats prefer fresh, running water over still water, prefer water placed away from their food (in the wild, water near a food source might be contaminated), and may reject water that tastes of chlorine or other chemicals.
Tricks to Increase Water Intake
Cat water fountains are one of the most effective interventions — a 2018 study in the Journal of Feline Medicine and Surgery found that cats with access to a water fountain drank significantly more than those with only a bowl. Other strategies include placing multiple water bowls in different locations, using wide, shallow bowls (cats prefer not to have their whiskers touch the sides), adding a small amount of low-sodium chicken broth to water, switching to or incorporating wet food into their diet, and trying different bowl materials (some cats prefer ceramic or glass over plastic).
Signs of Dehydration
The "skin tent test" is a quick home check: gently pinch the skin at the back of your cat's neck. In a hydrated cat, the skin snaps back immediately. If it takes more than 1–2 seconds, your cat may be dehydrated. Other signs include dry, tacky gums, sunken eyes, lethargy, decreased urination, and constipation. If you suspect dehydration, contact your vet — dehydrated cats may need subcutaneous fluids.