A common guideline is that a healthy cat needs about 3.5 to 4.5 ounces of water per 5 pounds of body weight per day (roughly 50 ml per kilogram), from all sources combined. An average 10-pound cat therefore needs around 7 to 9 ounces, about one cup, a day. That includes water in food, which changes the picture a lot.
Wet food vs dry food
- Wet food is about 75 to 80 percent water. Cats fed mostly wet food may drink very little from the bowl, and that is normal.
- Dry food contains only about 10 percent water, so cats on dry food need to drink much more.
Cats evolved from desert ancestors and have a naturally low thirst drive, so many cats on dry food drink less than ideal. Adequate hydration is linked to urinary tract health.
Signs of dehydration
- Lethargy and reduced appetite
- Dry or tacky gums
- Sunken eyes
- Skin that stays tented when gently lifted at the shoulders
- Constipation and small, dry stools
- Less urine in the litter box
Dehydration is serious, especially in kittens and older cats. Contact your vet.
When a cat drinks too much
A noticeable increase in drinking and urinating (bigger or more numerous clumps in the litter box, a bowl that empties faster) can be an early sign of:
- Chronic kidney disease, very common in older cats
- Diabetes
- Hyperthyroidism
- Urinary tract infection
Increased thirst always deserves a vet visit, see how often cats need checkups.
How to encourage your cat to drink more
- Add wet food to the diet, or a little water to wet food.
- Use a pet water fountain: many cats prefer moving water.
- Place several bowls around the house, away from the food bowl and the litter box.
- Use wide, shallow bowls of ceramic, glass or stainless steel: some cats dislike whiskers touching the sides.
- Change water daily and wash bowls regularly.
- Offer ice cubes or a few drops of tuna water (no salt) in a separate bowl as a treat.
Measuring at home
Fill a bowl with a measured amount of water in the morning and measure what is left 24 hours later, accounting for evaporation with a second bowl the cat cannot reach.
A cat eating more than usual can be another early warning sign, see why your cat is suddenly eating more.
