Water and hydration
How much water should a dog drink a day?
Last updated 23 September 2026 · How we write and check this
Short answer
Most healthy dogs need roughly 50 to 60 ml of water per kilogram of body weight each day, so a 20 kg dog drinks about 1 to 1.2 liters (34 to 40 fl oz). Active dogs, hot weather, and dry kibble diets push that number higher. Treat it as a guide, not a strict rule, and watch your dog's actual habits.
The formula behind the number
Vets commonly use 50 to 60 ml per kg as a starting point for water intake, based on typical maintenance fluid needs. A 5 kg terrier needs roughly 250 to 300 ml (8.5 to 10 fl oz) a day, while a 35 kg Labrador is closer to 1.75 to 2.1 liters (59 to 71 fl oz). This includes water drunk from a bowl plus moisture already in the food.
Why the real number moves around
A dog eating dry kibble, which is about 10 percent moisture, drinks noticeably more from the bowl than one eating wet food, which can be 70 to 80 percent water. Heat, exercise, nursing, and fever all raise the requirement, sometimes by 50 percent or more on a hot day. A dog resting indoors in mild weather often drinks toward the lower end of the range.
What matters more than the exact figure
Rather than measuring every milliliter, track whether your dog's intake stays roughly consistent week to week. Refill the bowl at the same times each day so a drop off or a spike is easy to notice. A sudden, sustained change in either direction is more useful information than hitting an exact daily target.
Key takeaways
- A rough guide is 50 to 60 ml of water per kg of body weight per day.
- Diet moisture, heat, and activity all shift the real number up or down.
- Wet food supplies much more water than dry kibble.
- Track consistency over time rather than chasing an exact figure.