How much water do you need a day?

About 2 to 2.5 liters a day in Europe, 2.7 to 3.7 liters in the US, counting all drinks and food. The European Food Safety Authority (EFSA) considers 2.0 liters of total water a day adequate for women and 2.5 liters for men. The US National Academies put the figures at about 2.7 liters for women and 3.7 liters for men.

Why do the two numbers differ?

They answer slightly different questions. EFSA set its values for adults in a moderate climate with moderate physical activity. The US report based its figures on the average total water intake of people who appeared to be well hydrated. Neither is a minimum that everyone must hit every day.

Does water from food count?

Yes. Both values are total water: plain water, every other drink, and the water in food. The US report estimates that about 80 percent of total water comes from drinks and about 20 percent from food, so the amount you actually drink is lower than the headline figure.

Do coffee and tea count?

They do. The US report counts drinking water and beverages, including caffeinated ones, toward total water.

What about hot weather and exercise?

Needs go up. The US report notes that people who are very physically active or who live in hot climates may need more water. It also notes that most healthy people meet their daily needs by letting thirst guide them.

How does Velora help?

You can log water in Velora and see it against the daily goal you set, and each entry is saved to Apple Health. Velora Coach adds short notes about your intake next to your steps and workouts, so water is part of the same daily picture.